Sample records for acetate membrane electrophoresis

  1. Counterflow immunoisotachophoresis on cellulose acetate membranes.

    PubMed

    Abelev, G I; Karamova, E R

    1984-11-01

    Discontinuous electrophoresis on cellulose acetate membranes with the use of 0.06 M Tris-HCl (pH 6.7) as the leading electrolyte and 0.012 M Tris-beta-alanine (pH 8.6) as the terminating one results in concentration of the proteins present in the system on the Cl-/beta-alanine- boundary. If the antigen solution is placed in a "pocket" ahead of the moving boundary, a counterflow to the cathode arises due to electroendosmosis. At constant voltage the migration rate of the boundary drops and that of electroendosmosis does not change until they become equal. In such a stationary position, the antigen-containing solution is passing through the Cl-/beta-alanine- boundary to the cathode, while all the proteins are completely "absorbed" on the boundary as highly concentrated bands. Addition of ampholytes to the antigen solution contributes to the isotachophoretic separation of a protein mixture on the strip. The concentrated and separated antigens can be revealed by immunofixation, immunodiffusion, or crossed immunoelectrophoresis in gel. The technique is approximately 100 times more sensitive compared to the usual immunodiffusion and immunoelectrophoresis methods on cellulose acetate membranes, and is applicable to the detection of trace amounts of antigens in the urine, liquor, amniotic fluid, tears, and other biological fluids with low protein contents. PMID:6528978

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

    PubMed Central

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

    2011-01-01

    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

  3. Rapid electrophoresis and quantitation of haemoglobins on cellulose acetate

    PubMed Central

    Marengo-Rowe, A. J.

    1965-01-01

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

  4. Application Studies of Cellulose Acetate and Polymethylmethacrylate Blend Ultrafiltration Membranes

    Microsoft Academic Search

    S. Vidya; D. Mohan

    2010-01-01

    The preparation of novel membranes based on cellulose acetate and polymethylmethacrylate blends in the absence and presence of the pore former by solution blending and ultrafiltration set up was carried out. The effect of compaction time on pure water flux at higher transmembrane pressure for various polymer compositions of the above blends both in the presence and absence of the

  5. Release of doxycycline through cellulose acetate symmetric and asymmetric membranes produced from recycled agroindustrial residue: Sugarcane bagasse

    Microsoft Academic Search

    Guimes Rodrigues Filho; Sabrina Dias Ribeiro; Carla da Silva Meireles; Leandro Gustavo da Silva; Reinaldo Ruggiero; Moacir Fernandes Ferreira; Daniel Alves Cerqueira; Rosana Maria Nascimento de Assunção; Mara Zeni; Patricia Polleto

    2011-01-01

    Cellulose acetate is one of the components employed in drug controlled-release systems in the form of membranes. The aim of this study was to examine the controlled-release of doxycycline employing cellulose acetate symmetric and asymmetric membranes as matrices. The cellulose triacetate was produced from sugarcane bagasse through a homogeneous acetylation reaction, using acetic acid as the solvent, acetic anhydride as

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

    Microsoft Academic Search

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

    1997-01-01

    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

  7. Cellulose Acetate and Polyetherimide Blend Ultrafiltration Membranes, I: Preparation, Characterization, and Application

    Microsoft Academic Search

    A. Nagendran; D. Lawrence Arockiasamy; D. Mohan

    2008-01-01

    Ultrafiltration (UF) techniques have particular advantages for simultaneous purification, concentration, and fractionation of macromolecules. In this study, polymeric blend ultrafiltration membranes based on cellulose acetate and polyetherimide were prepared by phase inversion technique and characterized in terms of compaction time, pure water flux (PWF), water content, membrane hydraulic resistance, and scanning electron microscopy (SEM). The blend membranes prepared were subjected

  8. Original article Two-dimensional gel electrophoresis of membrane

    E-print Network

    Paris-Sud XI, Université de

    — A membrane fraction was isolated from the ectomycorrhizal fungi Pisolithus tinctorius globulus / Pisolithus tinctorius / ectomycorrhiza / elec- trophoresis / membrane protein / symbiosis ectomycorhiziens Pisolithus tinctorius et Cenococcum geophilum et d'ectomycorhizes d'eucalyptus. L'observation par

  9. Phase-inversion cellulose acetate membranes for suppression of protein interferences in anodic stripping voltammetry

    Microsoft Academic Search

    Boy Hoyer; Nina Jensen

    1995-01-01

    The phase-inversion (PI) method was used to cast permselective cellulose acetate membranes on glassy carbon electrodes with the aim of suppressing protein interferences in anodic stripping voltammetry (ASV). By using cadmium and lead as test analytes and differential pulse ASV as detection method, it was found that the modification of the electrode greatly reduces the interference from albumin. Cellulose acetate

  10. A Study of Polydimethylsiloxane\\/Aromatic Polyamide Laminated Membranes for Separation of Acetic Acid\\/Water Mixtures by Pervaporation Process

    Microsoft Academic Search

    SHENGZHI DENG; S. SOURIRAJAN; T. MATSUURA

    1994-01-01

    Separation of acetic acid\\/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed,

  11. Demystifying Hardy-Weinberg: Using Cellulose Acetate Electrophoresis of the Lap Locus to Study Population Genetics in White Campion (Silene latifolia)

    NSDL National Science Digital Library

    Patricia A. Peroni (Davidson College; )

    1999-01-01

    This laboratory exercise could used as an introductory biology lab and/or an upper level course lab, with minor adjustments, covering ecology, evolution, population genetics and physiology. Population genetics is explored using seedlings from several population of the perennial herb white campion, (Silene latifolia), scientific method,cellulose acetate protein electrophoresis and the Hardy-Weinberg Equilibrium Theory.

  12. Continuous ethanol production with a membrane bioreactor at high acetic Acid concentrations.

    PubMed

    Ylitervo, Päivi; Franzén, Carl Johan; Taherzadeh, Mohammad J

    2014-01-01

    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

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

    PubMed Central

    Ylitervo, Päivi; Franzén, Carl Johan; Taherzadeh, Mohammad J.

    2014-01-01

    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

  14. Dehydration of ethyl acetate aqueous solution by pervaporation using PVA\\/PAN hollow fiber composite membrane

    Microsoft Academic Search

    Hai-Kuan Yuan; Jie Ren; Xiao-Hua Ma; Zhen-Liang Xu

    2011-01-01

    Using poly(vinyl alcohol) (PVA) as coating material, tartaric acid (Tac) and maleic anhydride (Mac) as cross-linking agents and the poly(acrylonitrile) (PAN) hollow fiber ultrafiltration membrane as support layer, the PVA\\/PAN composite membrane was prepared by dip-coating method used for pervaporation (PV) dehydration of ethyl acetate (EAc)\\/H2O solution. The PVA\\/PAN composite membrane was characterized by FT-IR spectra and SEM. The effects

  15. Dehydration of ethyl acetate–water mixtures using PVA\\/ceramic composite pervaporation membrane

    Microsoft Academic Search

    Shanshan Xia; Xueliang Dong; Yuexin Zhu; Wang Wei; Fenjuan Xiangli; Wanqin Jin

    2011-01-01

    Dehydration of ethyl acetate (EAC)–water mixtures by pervaporation (PV) was studied using a ceramic-supported polyvinyl alcohol (PVA) composite membrane. The effects of feed temperature, feed water content and feed flow rate on the PV performance of the membrane were systematically investigated. In addition, swelling experiments were performed to evaluate the sorption characteristic of the membrane. Flory-Huggins and NRTL (non-random two

  16. Pervaporation separation of ethyl acetate–ethanol binary mixtures using polydimethylsiloxane membranes

    Microsoft Academic Search

    A. Hasano?lu; Y. Salt; S. Kele?er; S. Özkan; S. Dinçer

    2005-01-01

    Pervaporation separation of azeotrope forming ethyl acetate–ethanol mixtures was investigated by using a selfmade polydimethylsiloxane (PDMS) membrane. Sorption, desorption and pervaporation experiments for ethyl acetate–ethanol mixture with different concentrations were conducted at 30, 40 and 50°C. The effect of process parameters such as feed concentration and temperature on flux and selectivity is discussed. Equilibrium curves are determined by vapor–liquid equilibrium

  17. Permeation performance of Cellulose acetate propionate\\/polyvinylidine fluoride blend membranes by phase inversion

    Microsoft Academic Search

    Kuo-Liang Chuang; Ming-Chi Hsieh; Yun-Chieh Su; Hui-Hsin Tseng; Li-Luen Huang

    2010-01-01

    In this study, cellulose acetate propionate (CAP) and polyvinylidene fluoride (PVDF) were selected to prepare porous-blend membrane by wet phase inversion method. The effect of the CAP and PVDF concentration of the casting solution on membrane morphology structure and thermal stability was investigated by scanning electron microscopy (SEM) and thermal gravimetry\\/differential scanning calorimetry (TGA\\/DSC). The pure water flux by the

  18. Glucose oxidase immobilization on a novel cellulose acetate–polymethylmethacrylate membrane

    Microsoft Academic Search

    S. Rauf; A. Ihsan; K. Akhtar; M. A. Ghauri; M. Rahman; M. A. Anwar; A. M. Khalid

    2006-01-01

    Glucose oxidase (GOD) was immobilized on cellulose acetate–polymethylmethacrylate (CA–PMMA) membrane. The immobilized GOD showed better performance as compared to the free enzyme in terms of thermal stability retaining 46% of the original activity at 70°C where the original activity corresponded to that obtained at 20°C. FT-IR and SEM were employed to study the membrane morphology and structure after treatment at

  19. Controlled release of triprolidine using ethylene-vinyl acetate membrane and matrix systems.

    PubMed

    Shin, Sang-Chul; Lee, Hyun-Jin

    2002-09-01

    The studies on the permeability of triprolidine through ethylene-vinyl acetate (EVA) copolymer membrane using two-chamber diffusion cell was carried out to develop the controlled delivery system. To evaluate the effect of drug concentration in reservoir, polyethylene glycol (PEG) 400 was added to saline solution as a solubilizer and a sink condition was maintained in the receptor solution. The permeation rate of drug through EVA membrane was proportional to PEG 400 volume fraction. A linear relationship existed between the permeation rate and the reciprocal of the membrane thickness. Triprolidine-containing matrix was fabricated with EVA copolymer to control the release of the drug. The plasticizers was added for preparing the pore structure of EVA membranes to increase the drug release. The effects of PEG 400, vinyl acetate (VA) contents of EVA, membrane thickness, drug concentration, temperature, and plasticizers, on drug release were studied. The release rate of drug from the EVA matrix increased with PEG 400 volume fraction, increased temperature and drug loading doses. An increased vinyl acetate comonomer content in EVA membrane increased the drug release rate and permeability coefficient. Among the plasticizers used such as alkyl citrates and phthalates, tetra ethyl citrate showed the best enhancing effects showing the enhancement factor of 1.88. The release of triprolidine from the EVA matrix follows a diffusion controlled model, where the quantity released per unit area is proportional to the square root of time. The controlled release of triprolidine could be achieved using the EVA polymer including the plasticizer. PMID:12191692

  20. Pervaporation of acetic acid\\/water mixtures through silicalite filled polydimethylsiloxane membranes

    Microsoft Academic Search

    Shih-Yuan Lu; Chung-Ping Chiu; Hsiang-Yuan Huang

    2000-01-01

    The preferential pervaporation of acetic acid over water is achieved with silicalite filled polydimethylsiloxane (PDMS) membranes. The effect of silicalite addition is not positive at the feed temperature of 25°C, but improves with increasing feed temperature. At a feed temperature of 45°C, silicalite addition enhances not only the separation factor but also the permeation flux of the pervaporation. This improvement

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

    PubMed

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

    2002-01-15

    Cellulose triacetate (CTA) ultrafilters and cellulose acetate blend (CAB) desalination membranes were treated with a radiofrequency gas plasma (tetrafluoromethane (CF(4)) or carbon dioxide (CO(2)), 47-49 W, 0.04-0.08 mbar). Treatment times were varied between 15 s and 120 min. The plasma-treated top layer of the membranes was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle measurements to obtain information about surface structure, chemistry, and wettability, respectively. The membrane properties (e.g., permeability, selectivity, fouling) were studied by waterflux measurements, molecular weight cutoff measurements, and fouling experiments with bovine serum albumin. CO(2) plasma treatment resulted in gradual etching of the membrane's dense top layer. Permeation and selectivity changed significantly for treatment times of 0-15 min for CTA and 5-60 min for CAB membranes. Moreover, CTA membranes were hydrophilized during CO(2) plasma treatment whereas CF(4) plasma treatment led to hydrophobic surfaces due to strong fluorination of the top layer. This study shows that gas plasma etching can tailor the properties of asymmetric cellulose acetate membranes by simultaneously modifying the chemistry and structure of the top layer. The low fouling properties of CTA membranes were thereby largely maintained. PMID:16290368

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

    SciTech Connect

    Deng, S.; Sourirajan, S.; Matsuura, T. (Univ. of Ottawa (Canada))

    1994-06-01

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

  3. Enzymatic activation of cellulose acetate membrane for reducing of protein fouling.

    PubMed

    Koseoglu-Imer, Derya Y; Dizge, Nadir; Koyuncu, Ismail

    2012-04-01

    In this study, the surface of cellulose acetate (CA) ultrafiltration membrane was activated with serine protease (Savinase) enzyme to reduce protein fouling. Enzyme molecules were covalently immobilized with glutaraldehyde (cross-linking agent) onto the surface of CA membranes. The membrane activation was verified using filtration experiments and morphological analysis. Scanning electron microscopy (SEM) images and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy of the activated membrane when compared with raw membrane were confirmed that the enzyme was immobilized onto the membrane surface. The immobilization efficiencies changed from 13.2 to 41.2% according to the enzyme ratios from 2.5 to 10.0 mg/mL. However, the permeability values decreased from 232±6 to 121±4 L/m(2) h bar with increasing enzyme concentration from 2.5 to 10.0 mg/mL. In fouling experiments, bovine serum albumin (BSA) was used as the protein model solution and activated sludge was used as the model biological sludge. Enzyme-activated membranes exhibited good filtration performances and protein rejection efficiencies were compared with raw CA membrane. Also the relative flux reduction (RFR) ratios of membranes were calculated as 97% and 88% for raw CA and enzyme-activated membranes (5 mg/mL savinase), respectively. The membrane activated with Savinase enzyme could be proposed as a surface treatment method before filtration to mitigate protein fouling. PMID:22218336

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

    PubMed

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

    2015-10-01

    Functionalized multi-walled carbon nanotube blended cellulose acetate (fCNT-CA) membranes were synthesized for forward osmosis (FO) through phase inversion. The membranes were characterized through SEM, FTIR, and water contact angle measurement. AFM was utilized to investigate alginate fouling mechanism on the membrane. It reveals that the fCNT contributes to advance alginate fouling resistance in FO (57% less normalized water flux decline for 1% fCNT-CA membrane was observed than that for bare CA membrane), due to enhanced electrostatic repulsion between the membrane and the alginate foulant. Furthermore, it was found that the fCNT-CA membranes became more hydrophilic due to carboxylic groups in functionalized carbon nanotube, resulting in approximately 50% higher water-permeated flux than bare CA membrane. This study presents not only the fabrication of fCNT-CA membrane and its application to FO, but also the quantification of the beneficial role of fCNT with respect to alginate fouling in FO. PMID:26022283

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

    PubMed

    Lee, Sang Cheol

    2015-09-01

    Selective removal of acetic acid from simulated hemicellulosic hydrolysates containing xylose and sulfuric acid was attempted in a batch emulsion liquid membrane (ELM) system with organophosphorus extractants. Various experimental variables were used to develop a more energy-efficient ELM process. Total operation time of an ELM run with a very small quantity of trioctylphosphine oxide as the extractant was reduced to about a third of those required to attain almost the same extraction efficiency as obtained in previous ELM works without any extractant. Under specific conditions, acetic acid was selectively separated with a high degree of extraction and insignificant loss of xylose, and its purity and enrichment ratio in the stripping phase were higher than 92% and 6, respectively. Also, reused organic membrane solutions exhibited the extraction efficiency as high as fresh organic solutions did. These results showed that the current ELM process would be quite practical. PMID:26056774

  6. Transport of lactate and acetate through the energized cytoplasmic membrane of Escherichia coli

    SciTech Connect

    Axe, D.D.; Bailey, J.E. [California Inst. of Technology, Pasadena, CA (United States). Div. of Chemistry and Chemical Engineering

    1995-07-05

    Escherichia coli produces lactate and acetate in significant amounts during both aerobic and anaerobic glycolysis. A model describing the mechanism of protein-mediated lactate transport has previously been proposed. A simple theoretical analysis here indicates that the proposed model would drain cellular energy resources by catalytically dissipating the proton-motive force. An experimental analysis of lactate and acetate transport employs nuclear magnetic resonance (NMR) spectroscopy to measure the relative concentrations of these end products on the two sides of the cytoplasmic membrane of anaerobically glycolyzing cells. Comparison of measured concentration ratios of those expected at equilibrium for various transport modes indicates that acetate is a classical uncoupling agent, permeating the membrane at comparable rates in the dissociated and undissociated forms. The lactate concentration ratio changes markedly after an initial period of sustained glycolysis. This change is most readily explained as resulting from a lactate transport system that responds to an indicator of glycolytic activity. The data further indicate that lactate permeates the membrane in both dissociated and undissociated forms. Both acids, then, are capable of catalytically dissipating the proton-motive force.

  7. Identification of the major membrane and core proteins of vaccinia virus by two-dimensional electrophoresis.

    PubMed Central

    Jensen, O N; Houthaeve, T; Shevchenko, A; Cudmore, S; Ashford, T; Mann, M; Griffiths, G; Krijnse Locker, J

    1996-01-01

    Vaccinia virus assembly has been well studied at the ultrastructural level, but little is known about the molecular events that occur during that process. Towards this goal, we have identified the major membrane and core proteins of the intracellular mature virus (IMV). Pure IMV preparations were subjected to Nonidet P-40 (NP-40) and dithiothreitol (DTT) treatment to separate the core proteins from the membrane proteins. These proteins were subsequently separated by two-dimensional (2D) gel electrophoresis, and the major polypeptide spots, as detected by silver staining and 35S labeling, were identified by either matrix-assisted laser desorption/ionization mass spectrometry, N-terminal amino acid sequencing, or immunoprecipitation with defined antibodies. Sixteen major spots that partitioned into the NP-40-DTT-soluble fraction were identified; 11 of these were previously described virally encoded proteins and 5 were cellular proteins, mostly of mitochondrial origin. The core fraction revealed four major spots of previously described core proteins, two of which were also detected in the membrane fraction. Subsequently, the NP-40-DTT-soluble and -insoluble fractions from purified virus preparations, separated by 2D gels, were compared with postnuclear supernatants of infected cells that had been metabolically labeled at late times (6 to 8 h) postinfection. This relatively short labeling period as well as the apparent shutoff of host protein synthesis allowed the selective detection in such postnuclear supernatants of virus-encoded proteins. These postnuclear supernatants were subsequently treated with Triton X-114 or with sodium carbonate to distinguish the membrane proteins from the soluble proteins. We have identified the major late membrane and nonmembrane proteins of the IMV as they occur in the virus as well as in infected cells. This 2D gel map should provide an important reference for future molecular studies of vaccinia virus morphogenesis. PMID:8892867

  8. A submerged nanofiltration membrane bioreactor for domestic wastewater treatment: the performance of cellulose acetate nanofiltration membranes for long-term operation

    Microsoft Academic Search

    Jae-Hoon Choi; Kensuke Fukushi; Kazuo Yamamoto

    2007-01-01

    A submerged nanofiltration membrane bioreactor (NF MBR) using cellulose acetate membranes was operated for 240 days to examine the performance of the NF membrane in domestic wastewater treatment. For the first 130 days, dissolved organic carbon (DOC) concentration in the permeates ranged from 0.5 to 2.0mg\\/L. The rejection rates of monovalent and divalent ions by the NF membranes varied between

  9. Kolbe electrolysis of acetic acid in a polymer electrolyte membrane reactor

    SciTech Connect

    Hicks, M.T.; Fedkiw, P.S. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering

    1998-11-01

    A polymer electrolyte membrane (PEM) reactor is described for use in Kolbe electrolysis: the anodic oxidation of an alkyl carboxylic acid with subsequent decarboxylation and coupling to yield a dimer, 2RCOOH {r_arrow} R-R + 2CO{sub 2} + 2e{sup {minus}} + 2H{sup +}. Platinized Nafion 117 is the PEM and functions simultaneously as the electrolyte and separator. Results demonstrating the feasibility of Kolbe electrolysis in a PEM reactor are presented for the oxidation of gaseous acetic acid (in a nitrogen diluent) to ethane and carbon dioxide, with hydrogen evolution at the counter electrode. The investigation includes the following effects on current density, current efficiency, and product selectivity: acetic acid partial pressure (P{sub total} {approx} 1 atm), cell voltage and temperature, phase of the catholyte (liquid water or humidified nitrogen), and the procedure used to prepare the membrane-electrode assembly. Current densities from 0.06 to 0.4 A/cm{sup 2} with Kolbe current efficiencies of 10 to 90% were obtained for cell voltages ranging from 4 to 10 V. The best results were obtained using PEMs platinized by a nonequilibrium impregnation-reduction method; a 75% current efficiency at 0.3 A/cm{sup 1} with a cell voltage of 6 V were measured at the following reaction conditions: 42 C reactor, 58 mm Hg acetic acid (50 C acetic acid dew point), and 42 C liquid water to the cathode. These initial results are encouraging for Kolbe electrolysis in a PEM cell; additional work, however, is needed to determine if the PEM strategy may be employed using a liquid-phase reactant. In addition, optimal reaction conditions and downstream mass-transfer separation requirements remain to be determined, both of which are reactant specific.

  10. Effect of Poly(ethylene glycol) on Separations by Cellulose Acetate\\/poly(ether imide) Blend Membranes

    Microsoft Academic Search

    A. Nagendran; D. Lawrence Arockiasamy; D. Mohan

    2007-01-01

    Ultrafiltration membranes are largely being applied for macromolecular and heavy metal ion separations from aqueous streams. In this study, cellulose acetate (CA) and polyetherimide (PEI) based ultrafiltration blend membranes prepared in the absence and presence of poly(ethylene glycol) 600 (PEG 600) in various compositions were subjected to the separation of macromolecular proteins such as bovine serum albumin (BSA), egg albumin

  11. Cross-linked HTPB-based polyurethaneurea membranes for recovery of ethyl acetate from aqueous solution by pervaporation

    Microsoft Academic Search

    Yunxiang Bai; Jinwen Qian; Chunfang Zhang; Lin Zhang; Quanfu An; Huanlin Chen

    2008-01-01

    Cross-linked hydroxy terminated polybutadiene (HTPB)-based polyurethaneurea (PU), HTPB–DVB–PU, was synthesized by a three-step polymerization process. It was firstly used as membrane material to recover aroma, ethyl acetate (EA), from aqueous solution by pervaporation (PV). The effects of the content of cross-linker DVB, EA concentration in feed, and operating temperature on the PV performance of HTPB–DVB–PU membranes were investigated. The membranes

  12. A novel blood plasma analysis technique combining membrane electrophoresis with silver nanoparticle-based SERS spectroscopy for potential applications in noninvasive cancer detection

    Microsoft Academic Search

    Juqiang Lin; Rong Chen; Shangyuan Feng; Jianji Pan; Yongzeng Li; Guannan Chen; Min Cheng; Zufang Huang; Yun Yu; Haishan Zeng

    2011-01-01

    Combining membrane electrophoresis with silver nanoparticle-based surface-enhanced Raman spectroscopy (SERS), we have developed a novel method for blood plasma analysis for cancer detection applications. In this method, total serum proteins are isolated from blood plasma by membrane electrophoresis and mixed with silver nanoparticles to perform SERS spectral analysis. The obtained SERS spectra present information-rich, fingerprint-type signatures of the biochemical constituents

  13. Glucose oxidase immobilization on a novel cellulose acetate-polymethylmethacrylate membrane.

    PubMed

    Rauf, S; Ihsan, A; Akhtar, K; Ghauri, M A; Rahman, M; Anwar, M A; Khalid, A M

    2006-02-10

    Glucose oxidase (GOD) was immobilized on cellulose acetate-polymethylmethacrylate (CA-PMMA) membrane. The immobilized GOD showed better performance as compared to the free enzyme in terms of thermal stability retaining 46% of the original activity at 70 degrees C where the original activity corresponded to that obtained at 20 degrees C. FT-IR and SEM were employed to study the membrane morphology and structure after treatment at 70 degrees C. The pH profile of the immobilized and the free enzyme was found to be similar. A 2.4-fold increase in Km value was observed after immobilization whereas Vmax value was lower for the immobilized GOD. Immobilized glucose oxidase showed improved operational stability by maintaining 33% of the initial activity after 35 cycles of repeated use and was found to retain 94% of activity after 1 month storage period. Improved resistance against urea denaturation was achieved and the immobilized glucose oxidase retained 50% of the activity without urea in the presence of 5M urea whereas free enzyme retained only 8% activity. PMID:16242200

  14. Sensitivity enhancement in direct coupling of supported liquid membrane extractions to capillary electrophoresis by means of transient isotachophoresis and large electrokinetic injections.

    PubMed

    Pant??ková, Pavla; Kubá?, Pavel; Bo?ek, Petr

    2015-04-10

    Enhanced sensitivity for determination of basic drugs in body fluids was achieved by in-line coupling of extraction across supported liquid membrane (SLM) to large electrokinetic injection and transient isotachophoresis-capillary zone electrophoresis (tITP-CZE) in commercial CZE instrument. Twelve cm long tITP plug of 300mM ammonium acetate was formed in the separation capillary just before the electrokinetic injection of acceptor solution containing nortriptyline, haloperidol and loperamide extracted across the SLM. The tITP plug ensured efficient stacking and preconcentration of the injected basic drugs due to the tITP action of ammonium and the drugs were then separated by CZE using 5.2M acetic acid as background electrolyte. No interferences were observed from highly-abundant body fluid species (NaCl and human serum albumin) due to the excellent clean-up properties of SLMs and analytical sensitivity increased up to 340 times compared to SLM extractions coupled in-line to CZE with standard hydrodynamic injections. The SLM-tITP-CZE method was characterized by good repeatability (RSDs of peak areas below 7.8%), linearity over two orders of magnitude (r(2) better than 0.994) and limits of detection (defined as 3×S/N) between 3 and 45?g/L. Interfacing of SLM extractions to CZE instrumentation was achieved by low-cost, disposable micro-extraction devices, which can be routinely prepared in every analytical laboratory. These devices eliminated sample carry-over, minimized the need for manual sample handling and ensured fully automated determination (including extraction, injection, preconcentration and separation) of the three basic drugs in 20?L of untreated body fluids. PMID:25747667

  15. Magnetic Targeted Delivery of Dexamethasone Acetate across the Round Window Membrane in Guinea Pigs

    PubMed Central

    Du, Xiaoping; Chen, Kejian; Kuriyavar, Satish; Kopke, Richard D.; Grady, Brian P.; Bourne, David H.; Li, Wei; Dormer, Kenneth J.

    2012-01-01

    Hypothesis Magnetically susceptible PLGA nanoparticles will effectively target the round window membrane (RWM) for delivery of dexamethasone-acetate (Dex-Ac) to the scala tympani. Background Targeted delivery of therapeutics to specific tissues can be accomplished using different targeting mechanisms. One technology includes iron oxide nanoparticles, susceptible to external magnetic fields. If a nanocomposite composed of biocompatible polymer (PLGA), magnetite, and Dex-Ac can be pulled into and across the mammalian RWM, drug delivery can be enhanced. Method In vitro targeting and release kinetics of PLGA-magnetite-Dex-Ac nanoparticles first were measured using a RWM model. Next, these optimized nanocomposites were targeted to the RWM by filling the niche in anesthetized guinea pigs. A permanent magnet was placed opposite the RWM for 1 hour. Cochlear soft tissues, perilymph, and RWM were harvested after euthanasia and steroid levels were measured using HPLC. Results Membrane transport, in vitro, proved optimal targeting using a lower particle magnetite concentration (1 versus 5 or 10 mg/ml). In vivo targeted PLGA-magnetite-Dex-Ac particles had an average size of 482.8 ± 158 nm (DLS) and an average zeta potential ?19.9 ± 3.3 mV. In 1 hour, there was significantly increased cochlear targeted delivery of Dex or Dex-Ac, compared with diffusion alone. Conclusion Superparamagnetic PLGA-magnetite-Dex-Ac nanoparticles under an external magnetic field (0.26 mT) for 1 hour significantly increased Dex-Ac delivery to the inner ear. The RWM was not completely permeated and also became loaded with nanocomposites, indicating that delivery to the cochlea would continue for weeks by PLGA degradation and passive diffusion. PMID:23187928

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

    PubMed

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

    2013-01-01

    A major obstacle in the widespread application of microfiltration membranes in the wet separation processes such as wastewater treatment is the decline of permeates flux as a result of fouling. This study reports on the surface modification of cellulose acetate (CA) microfiltration membrane with amino acid L-3,4-dihydroxy-phenylalanine (L-DOPA) to improve fouling resistance of the membrane. The membrane surface was characterised using Fourier transform infrared spectroscopy (FTIR), water contact angle and zeta potential measurement. Porosity measurement showed a slight decrease in membrane porosity due to coating. Static adsorption experiments revealed an improved resistance of the modified membranes towards the adhesion of bovine serum albumin (BSA) as the model foulant. Dead end membrane filtration tests exhibited that the fouling resistance of the modified membranes was improved. However, the effect of the modification depended on the foulant solution concentration. It is concluded that L-DOPA modification is a convenient and non-destructive approach to enable low-BSA adhesion surface modification of CA microfiltration membranes. Nevertheless, the extent of fouling resistance improvement depends on the foulant concentration. PMID:23985522

  17. Lithium Dodecyl Sulfate\\/Polyacrylamide Gel Electrophoresis of Thylakoid Membranes at 4 degrees C: Characterizations of Two Additional Chlorophyll A-Protein Complexes

    Microsoft Academic Search

    Philippe Delepelaire; Nam-Hai Chua

    1979-01-01

    Lithium dodecyl sulfate\\/polyacrylamide gel electrophoresis of Chlamydomonas reinhardtii thylakoid membranes at room temperature gave two chlorophyll-protein complexes, CP I and CP II, as had been reported previously. However, when the electrophoresis was performed at 4 degrees C, there was an increase in the amount of chlorophyll associated with CP I and CP II, and in addition, three other chlorophyll-protein complexes

  18. Fully denaturing two-dimensional electrophoresis of membrane proteins: a critical update. Thierry Rabilloud 1,2, Mireille Chevallet 1,2, Sylvie Luche 1,2, Ccile Lelong 1,2

    E-print Network

    Paris-Sud XI, Université de

    Fully denaturing two-dimensional electrophoresis of membrane proteins: a critical update. Thierry-dimensional electrophoresis separating only denatured proteins. Traditional 2D methods, i.e.methods using isoelectric focusing in the first dimension are compared to methods using only zone electrophoresis in both dimensions, i

  19. In situ hydrogen utilization for high fraction acetate production in mixed culture hollow-fiber membrane biofilm reactor.

    PubMed

    Zhang, Fang; Ding, Jing; Shen, Nan; Zhang, Yan; Ding, Zhaowei; Dai, Kun; Zeng, Raymond J

    2013-12-01

    Syngas fermentation is a promising route for resource recovery. Acetate is an important industrial chemical product and also an attractive precursor for liquid biofuels production. This study demonstrated high fraction acetate production from syngas (H? and CO?) in a hollow-fiber membrane biofilm reactor, in which the hydrogen utilizing efficiency reached 100% during the operational period. The maximum concentration of acetate in batch mode was 12.5 g/L, while the acetate concentration in continuous mode with a hydraulic retention time of 9 days was 3.6 ± 0.1 g/L. Since butyrate concentration was rather low and below 0.1 g/L, the acetate fraction was higher than 99% in both batch and continuous modes. Microbial community analysis showed that the biofilm was dominated by Clostridium spp., such as Clostridium ljungdahlii and Clostridium drakei, the percentage of which was 70.5%. This study demonstrates a potential technology for the in situ utilization of syngas and valuable chemical production. PMID:24196583

  20. Proteins of the Inner Membrane of Escherichia coli: Identification of Succinate Dehydrogenase by Polyacrylamide Gel Electrophoresis with sdh Amber Mutants

    PubMed Central

    Spencer, Margaret E.; Guest, J. R.

    1974-01-01

    The inner or cytoplasmic membrane fraction of the cell envelope of Escherichia coli was isolated by isopycnic centrifugation on sucrose gradients. The membrane proteins were analyzed by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels (8.5%), and up to 56 bands were resolved. Different preparations gave very similar patterns of proteins. Succinate dehydrogenase mutants (sdh) were isolated which could not grow on succinate minimal medium, although growth on fumarate was unimpaired. The protein patterns of inner membrane preparations from sdh amber mutants were compared with the wild type, and one major band was greatly reduced in the mutants. This component, which represented approximately 5% of the inner membrane protein, was restored by introducing an amber suppressor gene (supU), which also restored the Sdh+ phenotype. The band corresponded to a protein with a molecular weight of 67,000 daltons, which is close to that for the large subunits of the succinate dehydrogenases of Rhodospirillum rubrum and beef heart mitochondria. Images PMID:4591960

  1. Influence of solvent on the structure and performance of cellulose acetate membranes

    Microsoft Academic Search

    Zhansheng Li; Jizhong Ren; Anthony G. Fane; Dong Fei Li; Fook-Sin Wong

    2006-01-01

    The liquid–liquid demixing process of cellulose acetate (CA) in two nonvolatile solvents N-methyl-2-pyrrolidone (NMP) and ?-butyrolactone (GBL) coagulating in water was investigated. Due to the relatively “poor” solvency of GBL for cellulose acetate and the higher interaction parameter between GBL and water, the CA\\/GBL\\/H2O system exhibits a delayed liquid–liquid demixing, while the CA\\/NMP\\/H2O has an instantaneous one. The solvent quality

  2. Electrophoresis of cellular membrane components creates the directional cue guiding keratocyte galvanotaxis

    PubMed Central

    Allen, Greg M.; Mogilner, Alex; Theriot, Julie A.

    2013-01-01

    Summary Background Motile cells exposed to an external direct current electric field will reorient and migrate along the direction of the electric potential in a process known as galvanotaxis. The underlying physical mechanism that allows a cell to sense an electric field is unknown, although several plausible hypotheses have been proposed. In this work we evaluate the validity of each of these mechanisms. Results We find that the directional motile response of fish epidermal cells to the cathode in an electric field does not require extracellular sodium or potassium, is insensitive to membrane potential, and also insensitive to perturbation of calcium, sodium, hydrogen, or chloride ion transport across the plasma membrane. Cells migrate in the direction of applied forces from laminar fluid flow, but reversal of electroosmotic flow did not affect the galvanotactic response. Galvanotaxis fails when extracellular pH is below 6, which suggests that the effective charge of membrane components may be a crucial factor. Slowing the migration of membrane components with an increase in aqueous viscosity slows the kinetics of the galvanotactic response. In addition inhibition of PI3K reverses the cell’s response to the anode, suggesting the existence of multiple signaling pathways downstream of the galvanotactic signal. Conclusions Our results are most consistent with the hypothesis that electrophoretic redistribution of membrane components of the motile cell is the primary physical mechanism for motile cells to sense an electric field. This chemical polarization of the cellular membrane is then transduced by intracellular signaling pathways canonical to chemotaxis to dictate the cell’s direction of travel. PMID:23541731

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

    PubMed

    Li, Renjie; Liu, Lifen; Yang, Fenglin

    2014-09-15

    Conductive composite membrane-phytic acid (PA) doped polyaniline (PANI)/cellulose acetate (CA) (PANI-PA/CA) was prepared in a simple and environmental-friendly method, in which aniline was blended with CA/PA solution and polymerized before the phase conversion. The resultant composite membranes were characterized by SEM, EDX, FTIR-ATR, BET and electrical resistance measurements. When used as adsorbent for Hg(II) and Cr(VI) ions, the prepared composite membrane exhibits excellent adsorption capability. The adsorption of Hg(II) and Cr(VI) follows a pseudo-second-order kinetic model and best fits the Langmuir isotherm model, with the maximum adsorption capacity reaching 280.11 and 94.34 mg g(-1), respectively. The heavy metal loaded composite membrane can be regenerated and reused after treatment with acid or alkali solution, making it a promising and practical adsorbent for Hg(II) and Cr(VI) removal. Tests with river water were also carried out, indicating good performance and application. PMID:25127386

  4. Transmembrane electrophoresis of 8-anilino-1-naphthalenesulfonate through egg lecithin liposome membranes

    Microsoft Academic Search

    Nigel Gains; Alan P. Dawson

    1975-01-01

    Summary Valinomycin has been shown to increase the amount of 8-anilino-1-naphtha-lenesulfonate (ANS) bound to egg lecithin liposomes and also to increase the maximum fluorescence value, as derived from double reciprocal plots. The assay conditions were such that addition of valinomycin would not produce a transmembrane potential. The formation of a valinomycin potassium ANS complex in the micelle membrane is proposed.

  5. 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)...

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

    Microsoft Academic Search

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

    1991-01-01

    Highly purified tonoplast and plasmamembrane vesicles were isolated from microsomes of Catharanthus roseus (L.) G. Don. by preparative free-flow electrophoresis. The relative amounts of tonoplast and plasma-membrane vesicles in the total microsomes varied with the pH of the grinding medium. The most electronegative fractions were identified as tonoplast using nitrate-inhibited, azide-resistant Mg2+-ATPase and pyrophosphatase activities as enzyme markers. The least

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

    PubMed

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

    2011-03-01

    Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique for proteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gel electrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automated operation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolved proteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but is extremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MS detection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE) membranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDS bound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we can immunoblot and Coomassie-stain the proteins collected on these membranes. PMID:21309548

  8. Biocompatibility and interference eliminating property of pullulan acetate\\/polyethylene glycol\\/heparin membrane for the outer layer of an amperometric glucose sensor

    Microsoft Academic Search

    Won Jun Sung; Kun Na; You Han Bae

    2004-01-01

    This study reports the use of hydrophobically modified heparin, which is both biocompatible and permselective, as a surface coating material for glucose sensors. The biocompatibility of pullulan acetate (PA)\\/polyethylene glycol (PEG)\\/heparin membrane was investigated in terms of platelet adhesion. Scanning electron micrographs (SEM) of the membrane-coated glucose sensor after exposure to a platelet-rich plasma (PRP) solution showed that the PA\\/PEG\\/heparin

  9. Phorbol myristate acetate stimulates pinocytosis and membrane spreading in mouse peritoneal macrophages

    PubMed Central

    1980-01-01

    Phorbol myristate acetate (PMA) at a concentration of 0.01 microgram/ml causes an approximately threefold increase in surface area of resident, proteose-peptone-elicited, and thioglycolate-broth-elicited mouse peritoneal macrophages. Resident and proteose-peptone-elicited macrophages, cultured for 24 h in the presence of PMA, increase their pinocytic rate twofold in response to addition of PMA (0.01 microgram/ml) to the medium. Thioglycolate-broth-elicited macrophages, cultured for 24 h in the absence of PMA, immediately increase their pinocytic rate 2- to 3.5-fold in response to a single challenge with PMA (0.01 microgram/ml). Cytochalasin B, colchicine, and podophyllotoxin have only modest inhibitory effects on the basal rate of pinocytosis and on PMA-induced cellular spreading, but completely block the stimulatory effects of PMA on pinocytosis in thioglycolate- broth-elicited macrophages. Cytochalasin D markedly inhibits both basal and PMA-stimulated pinocytosis in these cells. Thus, PMA is a useful tool for studying mechanisms of macrophage spreading and for enhancing the overall rate of pinosome formation. PMID:7400219

  10. Sorption and diffusion of methyl substituted benzenes through cross-linked nitrile rubber\\/poly(ethylene co-vinyl acetate) blend membranes

    Microsoft Academic Search

    Aji Joseph; Asha Elizabeth Mathai; Sabu Thomas

    2003-01-01

    The diffusion and sorption of methyl substituted benzenes through cross-linked nitrile rubber\\/poly(ethylene co-vinyl acetate) (NBR\\/EVA) blend membranes has been studied. The influence of blend composition, cross-linking systems, temperature and size of penetrants on the transport behaviour has been analysed. It was observed that as the EVA content increases in the blends, the solvent uptake decreases. An increase in the penetrant

  11. Colorful Electrophoresis

    NSDL National Science Digital Library

    University of Utah

    2012-01-01

    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.

  12. Plasticizer effect and comparative evaluation of cellulose acetate and ethylcellulose-HPMC combination coatings as semipermeable membranes for oral osmotic pumps of naproxen sodium.

    PubMed

    Ramakrishna, N; Mishra, B

    2002-04-01

    The objective of this study was to compare the performance of cellulose acetate (CA) and ethylcellulose (EC)-HPMC combination coatings as semipermeable membranes (SPMs) for osmotic pump tablets (OPTs) of naproxen sodium (NPS) so as to deliver a constant, predetermined amount of drug in solution form over a fixed span of time, independent of external environmental conditions. Osmotic pump tablets were designed with different coating variables and optimized in terms of nature of plasticizer, membrane thickness, and orifice diameter. The effect of insertion of an inner microporous film around the NPS core to minimize deformation of the SPM due to peristaltic movement of the gut was also studied. Osmotic pump tablets composed of membranes with water-soluble plasticizer, propyleneglycol (PG), released drug mainly through diffusion, whereas those designed with CA and EC-HPMC (4:1) coats containing water-insoluble plasticizer, castor oil, released their contents by perfect zero-order kinetics over a prolonged period of time, though the average release rate that could be achieved with the EC-HPMC (4:1) membrane was only about half the rate achieved with the CA membrane for the same membrane thickness. Release rates for both the membranes decreased with increasing membrane thickness and were found to be independent of orifice diameter, agitation intensity, and pH of the dissolution medium. PMID:12056533

  13. Cationic electrophoresis.

    PubMed

    Buxbaum, Engelbert

    2012-01-01

    Denaturing, discontinuous electrophoresis in the presence of SDS has become a standard method for the protein scientist. However, there are situations where this method produces suboptimal results. In these cases, electrophoresis in the presence of positively charged detergents such as cetyltrimethylammonium bromide (CTAB) may work considerably better. Methods for electrophoresis and staining of such gels are presented. PMID:22585477

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

    PubMed

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

    2010-11-15

    The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the ?g m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All techniques and methods of this work are in line with the green analytical chemistry trends. PMID:21035648

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

    Microsoft Academic Search

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

    1997-01-01

    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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-01-01

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

  18. 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...

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

    PubMed Central

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

    2014-01-01

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

  20. Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling

    PubMed Central

    Wang, Ren-ke; He, Xue-song; Hu, Wei; Lux, Renate; Li, Ji-yao; Zhou, Xue-dong; Shi, Wen-yuan

    2011-01-01

    Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as “bait”: Fusobacterium nucleatum (F. nucleatum) whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans(S. mutans) whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the “bait” oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The “prey” bacterial mixtures (including known species or natural saliva samples) were added, unbound cells were washed off after the incubation period and the remaining cells were eluted using 0.2 mol·L?1 glycine. Genomic DNA was extracted, subjected to 16S rRNAPCR amplification and separation of the resulting PCR products by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F.nucleatum adhered to a variety of bacterial species including uncultivable and uncharacterized ones. This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species. PMID:21485313

  1. Role of bis(monoacylglycero)phosphate in propranolol binding to phospholipid membranes under acidic conditions as measured by high-performance frontal analysis/capillary electrophoresis.

    PubMed

    Hamaguchi, Ryohei; Kuroda, Yukihiro; Tanimoto, Toshiko; Haginaka, Jun

    2012-10-01

    Bis(monoacylglycero)phosphate (BMP) is localized in acidic organelles such as late endosomes or lysosomes. It has been reported that BMP levels increase under phospholipidosis induced by cationic amphiphilic drugs. In the present study, the effect of BMP on the binding of propranolol (PRO) to phospholipid liposomes under acidic conditions was investigated. Binding experiments were conducted by high-performance frontal analysis/capillary electrophoresis. PRO showed nonspecific binding to BMP-containing liposomes (BMP:phosphatidylcholine = 1:4), when numbers of bound drug molecules per lipid molecule (r) ranged 0.01-0.06. Total binding affinity increased depending on the BMP content. Binding affinity was decreased by low ionic strength, or by substitution of BMP with diacylglycerol, suggesting that electrostatic interactions were involved. The binding-enhancement effect of BMP was almost equivalent to that of phosphatidylglycerol, and slightly larger than that of phosphatidylserine. An acidic environment (pH 5.0) decreased total binding affinity to BMP-containing liposomes. This could be explained by the pH-partition theory (i.e., the loss in affinity was caused by a decrease in the neutral form of the drug accessible to the membrane core). These results suggest that PRO binding is enhanced by BMP in late endosomes or lysosomes, whereas an acidic environment weakens such binding. PMID:22996699

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

    EPA Science Inventory

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

  3. Gel Electrophoresis

    NSDL National Science Digital Library

    2011-08-20

    In this activity, learners simulate the process of DNA fingerprinting by using electricity to separate colored dyes. Learners use simple materials to assemble a comb (electrophoresis chamber) to hold the samples, make a 0.2% sodium bicarbonate buffer and 1% gel solution, connect a high voltage power supply, and prepare 5 different samples. Then learners test their model and observe each sample.

  4. Electricity generation coupled with wastewater treatment using a microbial fuel cell composed of a modified cathode with a ceramic membrane and cellulose acetate film.

    PubMed

    Seo, Ha Na; Lee, Woo Jin; Hwang, Tae Sik; Park, Doo Hyun

    2009-09-01

    A noncompartmented microbial fuel cell (NCMFC) composed of a Mn(IV)-carbon plate and a Fe(III)-carbon plate was used for electricity generation from organic wastewater without consumption of external energy. The Fe(III)-carbon plate, coated with a porous ceramic membrane and a semipermeable cellulose acetate film, was used as a cathode, which substituted for the catholyte and cathode. The Mn(IV)-carbon plate was used as an anode without a membrane or film coating. A solar cell connected to the NCMFC activated electricity generation and bacterial consumption of organic matter contained in the wastewater. More than 99 degrees of the organic matter was biochemically oxidized during wastewater flow through the four NCMFC units. A predominant bacterium isolated from the anode surface in both the conventional and the solar cell-linked NCMFC was found to be more than 99 degrees similar to a Mn(II)-oxidizing bacterium and Burkeholderia sp., based on 16S rDNA sequence analysis. The isolate reacted electrochemically with the Mn(IV)-modified anode and produced electricity in the NCMFC. After 90 days of incubation, a bacterial species that was enriched on the Mn(IV)-modified anode surface in all of the NCMFC units was found to be very similar to the initially isolated predominant species by comparing 16S rDNA sequences. PMID:19809261

  5. Using linoleic Acid embedded cellulose acetate membranes to in situ monitor polycyclic aromatic hydrocarbons in lakes and predict their bioavailability to submerged macrophytes.

    PubMed

    Tao, Yuqiang; Xue, Bin; Yao, Shuchun

    2015-05-19

    To date no passive sampler has been used to predict bioavailability of contaminants to macrophytes. Here a novel passive sampler, linoleic acid embedded cellulose acetate membrane (LAECAM), was developed and used to in situ measure the freely dissolved concentrations of ten polycyclic aromatic hydrocarbons in the sediment porewaters and the water columns of two lakes in both winter and summer and predict their bioavailability to the shoots of resident submerged macrophytes (Potamogeton malainus, Myriophyllum spicata, Najas minor All., and Vallisneria natans (Lour.) Hara). PAH sampling by LAECAMs could reach equilibrium within 21 days. The influence of temperature on LAECAM-water partition coefficients was 0.0008-0.0116 log units/°C. The method of LAECAM was comparable with the active sampling methods of liquid-liquid extraction combined with fDOC adjustment, centrifugation/solid-phase extraction (SPE), and filtration/SPE but had several advantages. After lipid normalization, concentrations of the PAHs in LAECAMs were not significantly different from those in the macrophytes. In contrast, concentrations of the PAHs in the triolein containing passive sampler (TECAM) deployed simultaneously with LAECAM were much higher. The results suggest that linoleic acid is more suitable than triolein as the model lipid for passive samplers to predict bioavailability of PAHs to submerged macrophytes. PMID:25877046

  6. Agarose gel electrophoresis Solutions and reagents

    E-print Network

    Abou Elela, Sherif

    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

  7. Eslicarbazepine acetate.

    PubMed

    McCormack, Paul L; Robinson, Dean M

    2009-01-01

    Eslicarbazepine acetate, a prodrug of eslicarbazepine (S-licarbazepine), is a novel, voltage-gated sodium channel antagonist under development for the adjunctive treatment of adult patients experiencing treatment-refractory partial-onset seizures. * In phase III trials, eslicarbazepine acetate 800 and 1200 mg once daily significantly reduced seizure frequency compared with placebo over 12 weeks of maintenance treatment in adults experiencing partial-onset seizures who were taking 1-3 concomitant antiepileptic drugs. * During long-term, open-label treatment for up to 1 year, eslicarbazepine acetate at a median dosage of 800 mg once daily produced sustained reductions from baseline in seizure frequency. * Long-term treatment with eslicarbazepine acetate significantly improved from baseline health-related quality of life as assessed by the Quality-of-Life in Epilepsy Inventory-31 instrument. Similarly, eslicarbazepine acetate significantly reduced depressive symptoms assessed by the Montgomery-Asberg Depression Rating Scale. * Eslicarbazepine acetate was generally well tolerated in clinical trials. The majority of treatment-emergent adverse events were of mild to moderate severity and most occurred early in treatment. PMID:19062776

  8. 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

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

    2012-01-01

    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

  9. Electrokinetic motion of heterogeneous particles Electrophoresis, induced-charge electrophoresis, transverse electrophoresis.

    E-print Network

    Bazant, Martin Z.

    Electrokinetic motion of heterogeneous particles Synonyms Electrophoresis, induced-charge electrophoresis, transverse electrophoresis. Definition The electrokinetic motion of heterogeneous particles due to the combined effects of electrophoresis, induced-charge electrophoresis, and dielectrophoresis

  10. Western Blotting using Capillary Electrophoresis

    PubMed Central

    Anderson, Gwendolyn J.; Cipolla, Cynthia; Kennedy, Robert T.

    2011-01-01

    A microscale Western blotting system based on separating sodium-dodecyl sulfate protein complexes by capillary gel electrophoresis followed by deposition onto a blotting membrane for immunoassay is described. In the system, the separation capillary is grounded through a sheath capillary to a mobile X-Y translation stage which moves a blotting membrane past the capillary outlet for protein deposition. The blotting membrane is moistened with a methanol and buffer mixture to facilitate protein adsorption. Although discrete protein zones could be detected, bands were broadened by ~1.7-fold by transfer to membrane. A complete Western blot for lysozyme was completed in about one hour with 50 pg mass detection limit from low microgram per milliliter samples. These results demonstrate substantial reduction in time requirements and improvement in mass sensitivity compared to conventional Western blots. Western blotting using capillary electrophoresis shows promise to analyze low volume samples with reduced reagents and time, while retaining the information content of a typical Western blot. PMID:21265514

  11. Kidney cell electrophoresis

    NASA Technical Reports Server (NTRS)

    Todd, P. W.

    1985-01-01

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

  12. Investigation of unique interactions between cellulose acetate and ionic liquid [EMIM]SCN, and their influences on hollow fiber ultrafiltration membranes

    Microsoft Academic Search

    Ding Yu Xing; Na Peng; Tai-Shung Chung

    2011-01-01

    This study investigates the molecular interactions between ionic liquid, 1-ethyl-3-methylimidazolium thiocyanate ([EMIM]SCN) and cellulose acetate (CA), employing not only experimental characterizations including FTIR and rheological tests, but also molecular dynamics simulations. Due to the electrostatic nature of ionic liquids, [EMIM]SCN interacts intensely with CA molecules through pronounced hydrogen bonding, Coulombic forces and van der Waals interactions, which play an important

  13. Electrophoresis. Author manuscript Improvement of the solubilization of proteins in two-dimensional

    E-print Network

    Paris-Sud XI, Université de

    Electrophoresis. Author manuscript Page /1 10 Improvement of the solubilization of proteins in two-dimensional electrophoresis with immobilized pH gradients Rabilloud Thierry 1 * , Adessi C. 3 , Giraudel A. 2 , Lunardi J. 1 of sparingly-soluble (membrane and nuclear) proteins by high resolution two-dimensional electrophoresis. IEF

  14. Automatic multiple applicator electrophoresis

    NASA Technical Reports Server (NTRS)

    Grunbaum, B. W.

    1977-01-01

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

  15. Improved Electrophoresis Cell

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  16. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  17. Electrophoresis operations in space

    NASA Technical Reports Server (NTRS)

    Richman, D. W.

    1982-01-01

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

  18. Pallidol hexa­acetate ethyl acetate monosolvate

    PubMed Central

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

    2013-01-01

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

  19. Gel Electrophoresis of Dyes

    NSDL National Science Digital Library

    Janice Stephens

    2011-01-01

    In this experiment related to plant biotechnology, learners discover how to prepare and load an electrophoresis gel. They will then run the gels in an electrophoresis system to separate several dyes that are of different molecular sizes and carry different charges. This technique is fundamental to many of the procedures used in biotechnology. This lesson guide includes background information for the educator, safety precautions, and questions with answers for learners. For safety reasons, adult supervision is recommended. Modifications for use with younger learners are described in a related PDF (see related resource).

  20. Automatic multiple-sample applicator and electrophoresis apparatus

    NASA Technical Reports Server (NTRS)

    Grunbaum, B. W. (inventor)

    1977-01-01

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

  1. Capillary Electrophoresis of DNA

    Microsoft Academic Search

    Beatriz Sanchez-Vega

    Capillary electrophoresis (CE) separations are carried out inside a capillary tube, which usually has a diameter of 50 µm to facilitate temperature control. The length of the capillary differs in different applications, but it is typically in the region of 20–50 cm. The capillaries most widely used are fused silica covered with an external protective coating. A small portion of

  2. Cationic electrophoresis and eastern blotting.

    PubMed

    Buxbaum, Engelbert

    2015-01-01

    Denaturing, discontinuous electrophoresis in the presence of SDS has become a standard method for the protein scientist. However, there are situations where this method produces suboptimal results. In these cases electrophoresis in the presence of positively charged detergents like cetyltrimethylammonium bromide (CTAB) may work considerably better. Methods for electrophoresis, staining, and blotting of such gels are presented. PMID:26044000

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

    Microsoft Academic Search

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

    1989-01-01

    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

  4. Preparation of vinyl acetate

    DOEpatents

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

    1998-01-01

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

  5. Electrophoresis of positioned nucleosomes

    E-print Network

    Castelnovo, M; Castelnovo, Martin

    2007-01-01

    We present in this paper an original approach to compute the electrophoretic mobility of rigid nucleo-protein complexes like nucleosomes. This model allows to address theoretically the influence of complex position along DNA, as well as wrapped length of DNA on the electrophoretic mobility of the complex. The predictions of the model are in qualitative agreement with experimental results on mononucleosomes assembled on short DNA fragments (electrophoresis.

  6. Electrophoresis experiments in microgravity

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S.; Rhodes, Percy H.

    1991-01-01

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

  7. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1998-04-21

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

  8. Multiplexed capillary electrophoresis system

    SciTech Connect

    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

    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.

  9. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1998-04-21

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

  10. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1996-12-10

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

  11. Norethisterone and norethisterone acetate.

    PubMed

    1979-12-01

    This monograph on norethisterone and its acetate (NOR) includes chemical and physical data (synonyms and trade names), structural and molecular formulae and molecular weight of NOR, chemical and physical properties of NOR, and the production, use, occurrence, and analysis of NOR. Production of NOR and its acetate, both of which are not known to occur naturally, occurs via conversion of estrone to its methyl ester which is reduced to estradiol 3-methyl ether with lithium aluminum hydride; NOR acetate is synthesized by acetylating NOR with acetic anhydride in pyridine. NOR has been used for human medicine in a variety of ways: 1) to treat amenorrhea, 2) to treat dysfunctional uterine bleeding, and 3) for treating endometriosis. It has also been used to treat premenstrual tension and dysmenorrhea. Medicinal use of NOR acetate is similar to that for NOR. Analytical procedures for determining NOR as a bulk chemical are presented tabularly. Biological data relevant to the evaluation of carcinogenic risk to humans are presented briefly. With experimental animals, when administered alone NOR and/or its acetate increased the incidence of benign liver tumors in male mice and of pituitary tumors in females; females also suffered granulosa-cell ovarian tumors. NOR in combination with an estrogen increased incidence of pituitary tumors in mice of both sexes. NOR is embryolethal in some species and produces virilization in female fetuses. It is concluded that there is limited evidence for the carcinogenicity of NOR and its acetate in animals. Human studies are not available, but NOR is implicated causally as a progestogenic element in side effects of combined oral contraceptive usage. PMID:120838

  12. Capillary electrophoresis in clinical chemistry

    Microsoft Academic Search

    Rainer Lehmann; Wolfgang Voelter; Hartmut M. Liebich

    1997-01-01

    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

  13. Static continuous electrophoresis device

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H. (inventor)

    1982-01-01

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

  14. Effects of acetic acid\\/acetic anhydride ratios on the properties of corn starch acetates

    Microsoft Academic Search

    Cherif Ibrahima Khalil Diop; Hai Long Li; Bi Jun Xie; John Shi

    2011-01-01

    Corn starch was pre-treated with acetic acid and then acetylated by acetic anhydride under microwave irradiation. The effects of molar ratios of these two reagents on the acetylation of starch were investigated. Starch acetate with a high degree of substitution (DS, 2.93) was obtained at a molar ratio (acetic acid\\/acetic anhydride) of 1:1. However, the DS should tend to decrease

  15. Automated dual capillary electrophoresis system with hydrodynamic injection for the concurrent determination of cations and anions.

    PubMed

    Pham, Thi Thanh Thuy; Mai, Thanh Duc; Nguyen, Thanh Dam; Sáiz, Jorge; Pham, Hung Viet; Hauser, Peter C

    2014-09-01

    The capillary electrophoresis instrument developed for the concurrent determination of cations and anions features two separate capillaries and individual detectors to allow independent optimization for each group of ions. The capillaries are joined in a common injector block. The sample is drawn into the injector with a small membrane pump and automated simultaneous injection into both capillaries is achieved by pressurization of the fluid with compressed air. Flushing of the injector and of the capillaries with the background electrolyte is also carried out automatically by the same means. The buffer consisted of 12mM histidine and 2mM 18-crown-6 adjusted to pH 4 with acetic acid and was suitable for the contactless conductivity detection employed. The system was optimized for the determination of cationic NH4(+) and anionic NO3(-) and NO2(-), and linear calibration curves from about 20?M up to about 1.5mM were obtained for these ions. In a test run over 8h, the reproducibility for the peak areas was within ±7%. For demonstration, the instrument was successfully applied to the concurrent monitoring of the concentrations of the three ions during the biological removal of ammonium from contaminated groundwater in a sequencing batch reactor, where NO3(-) and NO2(-) are formed as intermediate products. PMID:25109864

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

    PubMed

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

    2002-09-01

    Glycoalkaloids are naturally occurring nitrogen-containing compounds present in many species of the family Solanaceae, including cultivated and wild potatoes (Solanum spp.), tomatoes (Lycopersicon spp.), etc. These compounds have pharmacological and toxicological effects on humans due to their significant anticholinesterase activity and disruption of cell membranes. Herein is reported the development of a capillary electrophoresis (CE) method using nonaqueous (NA) separation solutions in combination with ion trap mass spectrometry (MS and MS/MS) detection for the identification and quantification of glycoalkaloids and their relative aglycones. A mixture 90:10 v/v of MeCN-MeOH containing 50 mM ammonium acetate and 1.2 M acetic acid (applied voltage of 25.5 kV) was selected as a good compromise for the separation and detection of these compounds. The electrospray MS measurements were carried out in the positive ionization mode using a coaxial sheath liquid, methanol-water (1:1) with 1% of acetic acid at a flow rate of 2.5 microL/min. Under optimized experimental conditions, the predominant ion was the protonated molecular ion ([M+H](+)) of solanidine (m/z = 398), tomatidine (m/z = 416), chaconine (m/z = 852), solanine (m/z = 868), and tomatine (m/z = 1034). MS/MS experiments were carried out systematically by changing the relative collisional energy and monitoring the intensities of the fragment ions that were not high enough to allow better quantification than with the mother ions. The method was used for analyzing glycoalkaloids in potato extracts. PMID:12207298

  17. Fragrance material review on ?-methylbenzyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of ?-methylbenzyl acetate when used as a fragrance ingredient is presented. ?-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ?-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406576

  18. Fragrance material review on benzyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of benzyl acetate when used as a fragrance ingredient is presented. Benzyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for benzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, toxicokinetics, repeated dose, reproductive toxicity, genotoxicity, or carcinogenicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Refer Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22387848

  19. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

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

    2005-08-09

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

  20. DNA typing by capillary electrophoresis

    SciTech Connect

    Zhang, N.

    1997-10-08

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

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

    E-print Network

    Barron, Annelise E.

    Electrophoresis 1994, IS, 591-615 Capillary electrophoresis of DNA in ultradilute polymer solutions electrophoresis in ultradilute polymer solutions Using capillary electrophoresis, large DNA molecules (2 separations in such dilute polymer solutions. Electrophoresis experiments employing solutions of both small

  2. Ulipristal acetate: in uterine fibroids.

    PubMed

    Croxtall, Jamie D

    2012-05-28

    Ulipristal acetate, a selective progesterone-receptor modulator, inhibits the proliferation and induces apoptosis of leiomyoma cells in vitro. It also modulates the expression of vascular endothelial growth factors and hormone receptors and modulates extracellular matrix breakdown in leiomyoma cells but not in myometrial cells. In two randomized, double-blind, multinational phase III trials of 13 weeks' duration in women aged 18-50 years with uterine fibroids, a once-daily regimen of oral ulipristal acetate 5 mg/day controlled excessive uterine bleeding (primary endpoint) in ?90% of patients. Ulipristal acetate 5 mg/day was more effective than placebo and was shown to be noninferior to intramuscular leuprolide acetate 3.75 mg once monthly in controlling uterine bleeding. Uterine bleeding was rapidly controlled by ulipristal acetate. Approximately half of recipients of ulipristal acetate 5 mg/day became amenorrhoeic within the first 10 days of treatment. Furthermore, uterine bleeding was controlled significantly more rapidly for recipients of ulipristal acetate than recipients of leuprolide acetate. A significantly greater median reduction from baseline in total fibroid volume was observed for recipients of ulipristal acetate 5 mg once daily than recipients of placebo following 13 weeks' treatment (coprimary endpoint). For patients who did not undergo surgery, the volume reduction was maintained for at least 6 months after discontinuing treatment. Ulipristal acetate was generally well tolerated in women with uterine fibroids. The incidence of hot flush occurred with a significantly lower frequency for recipients of ulipristal acetate than for recipients of leuprolide acetate. PMID:22568731

  3. Mode of Action of the Antibacterial Compound Dequalinium Acetate

    PubMed Central

    Hugo, W. B.; Frier, M.

    1969-01-01

    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

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

    SciTech Connect

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

    2014-10-27

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

  5. Vinegar as a burn-down herbicide: Acetic acid concentrations, application volumes, and adjuvants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetic acid acts as a contact herbicide, injuring and killing plants by first destroying the cell membranes, which causes the rapid desiccation of the plant tissues. Vinegars with acetic acid concentrations of 11% or greater can burn the skin and cause serious to severe eye injury, including blindn...

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

    PubMed

    Mrozik, Wojciech; Markowska, Aleksandra; Guzik, Lukasz; Kraska, Bart?omiej; Kamysz, Wojciech

    2012-03-01

    The utility of three various analytical techniques [ion chromatography (IC), capillary electrophoresis (CE) and isotachophoresis (ITP)] was tested in the determination of counter-ions in synthetic peptides. The analyzed ions were acetates, trifluoroacetates and chlorides. IC provided the best results; CE, except limit of detection and limit of quantification, exhibited the comparable results. ITP was classified as the less useful because of the problem with the determination of the chloride ions. Nevertheless, all the three techniques were able to analyze trifluoroacetates and acetates ions with satisfactory results. Except analytical methods, three procedures using hydrochloric acid (HCl) (at two different concentrations) and acetic acid as sample solvents processed by lyophilization were tested. It has been found that the lyophilization not only by HCl but also by acetic acid is a simple and cheap procedure for removal of toxic trifluoroacetic counter-ions from peptides on satisfactory levels. PMID:22252914

  7. Contactless conductivity detector for microchip capillary electrophoresis

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  8. 4-Carbamoylpiperidinium acetate monohydrate.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2010-01-01

    In the structure of the title compound, C(6)H(13)N(2)O(+)·C(2)H(3)O(2) (-)·H(2)O, the amide H atoms of the cations form centrosymmetric cyclic hydrogen-bonding associations incorporating two water mol-ecules [graph set R(4) (2)(8)], which are conjoint with cyclic water-bridged amide-amide associations [R(4) (4)(12)] and larger R(4) (4)(20) associations involving the water mol-ecule and the acetate anions, which bridge through the piperidinium H-bond donors, giving an overall three-dimensional framework structure. PMID:21589458

  9. 4-Carbamoylpiperidinium acetate monohydrate

    PubMed Central

    Smith, Graham; Wermuth, Urs D.

    2010-01-01

    In the structure of the title compound, C6H13N2O+·C2H3O2 ?·H2O, the amide H atoms of the cations form centrosymmetric cyclic hydrogen-bonding associations incorporating two water mol­ecules [graph set R 4 2(8)], which are conjoint with cyclic water-bridged amide–amide associations [R 4 4(12)] and larger R 4 4(20) associations involving the water mol­ecule and the acetate anions, which bridge through the piperidinium H-bond donors, giving an overall three-dimensional framework structure. PMID:21589458

  10. Electrophoresis experiment, experiment MA-014

    NASA Technical Reports Server (NTRS)

    Hannig, K.; Wirth, H.

    1976-01-01

    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.

  11. Electrophoresis experiment. Experiment MA-014

    NASA Technical Reports Server (NTRS)

    Hannig, K. H.

    1977-01-01

    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 onto a photodiode system. The data evaluation indicates 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 final analysis of scientific data by computer processing shows the expected distribution of separated cells.

  12. Adsorption thermodynamics studies of 2,4,5-trichlorophenoxy acetic acid on poly-o-toluidine Zr(IV) phosphate, a nano-composite used as pesticide sensitive membrane electrode

    Microsoft Academic Search

    Asif Ali Khan; Tabassum Akhtar

    2011-01-01

    2,4,5-Trichlorophenoxy acetic acid (2,4,5-T) is used in forestry and in agriculture as a systemic herbicide (for eradication of undergrowth, etc). Adsorption behaviour of 2,4,5-T on the surface of poly-o-toluidine Zr(IV)phosphate was studied and some thermodynamic parameters such as Freundlich constants and Langmuir constants were determined on the surface of cation-exchanger. In this work, the adsorption of 2,4,5-T on cation-exchanger from

  13. Biocompatibility of dialysis membranes: Effects of chronic complement activation

    Microsoft Academic Search

    Raymond M Hakim; Douglas T Fearon; J Michael Lazarus; Cynthia S Perzanowski

    1984-01-01

    Biocompatibility of dialysis membranes: Effects of chronic complement activation. The ability of three dialysis membranes (cuprophane, cellulose acetate, and polymethylmethacrylate) to activate complement was studied prospectively in ten chronic dialysis patients using new and reused membranes. Patients were dialyzed for 1 month with each type of membrane. New cuprophane membranes caused the most intense activation, while polymethylmethacrylate (PMMA) surfaces caused

  14. Nonaqueous capillary electrophoresis conditions for the simultaneous separation of eight alpha-adrenergic blocking agents

    Microsoft Academic Search

    Qinhua Chen; Peng Li; Handong Yang; Bing Li; Jun Zhu; Lin Peng

    2010-01-01

    The analysis is described for the first time for separating eight alpha-adrenergic blocking agents (oxymetazoline, 5-methylurapidil,\\u000a prazosin, phentolamine, RS-17053, methoxamine, yohimbine, and BMY7378) by capillary electrophoresis (CE) with UV detection.\\u000a Optimum separation of the analytes was obtained on a 50 cm?×?75 ?m i.d. capillary using a buffer containing 20% acetonitrile,\\u000a 60 mM ammonium acetate, and 1.0% glacial acetic in methanol medium, with applied

  15. Insulin stacking for capillary electrophoresis

    Microsoft Academic Search

    Z. K Shihabi; M Friedberg

    1998-01-01

    Stacking methods are very important in overcoming the poor detection limits in capillary electrophoresis. Human insulin, a polypeptide, was concentrated on the capillary (stacked) based on three different and simple treatment methods to the sample: dilute buffers, high salt content, and acetonitrile (66%) were added to the sample to induce stacking. A dilute buffer in the sample caused a limited

  16. Capillary electrophoresis in food analysis

    Microsoft Academic Search

    Yiyang Dong

    1999-01-01

    Unlike other chromatographic methods such as gas chromatography and high performance liquid chromatography which were routinely used in almost all food labs, capillary electrophoresis is relatively a novice in food science, the detection limits and low process sample volume is the Achilles’ heel of this technique. Nevertheless, with ease of its high resolving power, rapid method development, easy sample preparation

  17. Electrically assisted liquid-phase microextraction combined with capillary electrophoresis for quantification of propranolol enantiomers in human body fluids.

    PubMed

    Tabani, Hadi; Fakhari, Ali Reza; Shahsavani, Abolfath; Gharari Alibabaou, Hossein

    2014-05-01

    In this study, electromembrane extraction (EME) combined with cyclodextrin (CD)-modified capillary electrophoresis (CE) was applied for the extraction, separation, and quantification of propranolol (PRO) enantiomers from biological samples. The PRO enantiomers were extracted from aqueous donor solutions, through a supported liquid membrane (SLM) consisting of 2-nitrophenyl octyl ether (NPOE) impregnated on the wall of the hollow fiber, and into a 20-?L acidic aqueous acceptor solution into the lumen of hollow fiber. Important parameters affecting EME efficiency such as extraction voltage, extraction time, pH of the donor and acceptor solutions were optimized using a Box-Behnken design (BBD). Then, under these optimized conditions, the acceptor solution was analyzed using an optimized CD-modified CE. Several types of CD were evaluated and best results were obtained using a fused-silica capillary with ammonium acetate (80?mM, pH?2.5) containing 8?mM hydroxypropyl-?-CD as a chiral selector, applied voltage of 18?kV, and temperature of 20°C. The relative recoveries were obtained in the range of 78-95%. Finally, the performance of the present method was evaluated for the extraction and determination of PRO enantiomers in real biological samples. PMID:24639338

  18. Electrokinetic motion of polarizable particles Dielectrophoresis, induced-charge electrophoresis, electrophoresis of the second kind.

    E-print Network

    Bazant, Martin Z.

    -charge electrophoresis, electrophoresis of the second kind. Definition The electrokinetic motion of polarizable particles results from electro-osmotic flow (induced- charge electrophoresis) of the first of second kind, in addition to electrostatic forces (dielectrophoresis). Overview The classical theory of electrophoresis

  19. Optimization of Turn Geometries for Microchip Electrophoresis

    E-print Network

    Santiago, Juan G.

    Optimization of Turn Geometries for Microchip Electrophoresis Joshua I. Molho,* Amy E. Herr, Bruce the performance of miniaturized electrophoresis systems that utilize dispersion-introduc- ing turns-chip capillary electrophoresis (CE) is an important separation technique for microfluidic devices.1 Several

  20. Techniques For Focusing In Zone Electrophoresis

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  1. Molecular Structure of Phenylmercuric acetate

    NSDL National Science Digital Library

    2004-11-10

    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.

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

    SciTech Connect

    Snyder, S. W.; Energy Systems

    2010-02-08

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

  3. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  4. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  5. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  6. 21 CFR 582.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Sodium acetate. 582.1721 Section 582...Purpose Food Additives § 582.1721 Sodium acetate. (a) Product. Sodium acetate. (b) Conditions of use. This substance is generally...

  7. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight. (2...C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by weight....

  8. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight. (2...C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by weight....

  9. Enhancing Centrifugal Separation With Electrophoresis

    NASA Technical Reports Server (NTRS)

    Herrmann, F. T.

    1986-01-01

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

  10. Ulipristal acetate for emergency contraception.

    PubMed

    Russo, J A; Creinin, M D

    2010-09-01

    Ulipristal acetate is a progesterone receptor modulator. As an emergency contraceptive, a 30-mg micronized formulation is effective for use up to 120 h from unprotected sexual intercourse. Ulipristal acetate acts as an antagonist of the progesterone receptor at the transcriptional level and a competitive antagonist of glucocorticoid receptor function. In contrast to other contraceptives, it has little effect on sex hormone-binding globulin. Although a single small study demonstrated some potential endometrial effects after ulipristal acetate administration, the clinical relevance of these findings is unclear. The incidence of adverse events in clinical trials for emergency contraception has typically been minimal, with one study showing a higher than expected incidence of nausea upon ulipristal acetate use. Ulipristal acetate, like other emergency contraceptive products, can lengthen the time to the next expected menstruation. Ulipristal acetate may have several advantages over currently approved emergency contraceptives. When compared to levonorgestrel, ulipristal acetate maintains its efficacy for a full 120 h, whereas levonorgestrel formulations have declining efficacy over that time frame. Moreover, although the copper intrauterine device (IUD) is highly effective as an emergency contraceptive, accessibility is an issue since the IUD requires a skilled provider for insertion. PMID:20967297

  11. The Role of Electrophoresis in Gene Electrotransfer M. Pavlin K. Flisar M. Kanduser

    E-print Network

    Ljubljana, University of

    ). Recent studies showed that gene electrotransfer is a promising method for cancer gene therapy, DNA-voltage pulses to increase the permeability of a cell membrane and enables transfer of genes. Poor plasmid therapy. Therefore, we analyzed the effect of electrophoresis on increasing gene electrotransfer effi

  12. Charge Shift Electrophoresis: Simple Method for Distinguishing between Amphiphilic and Hydrophilic Proteins in Detergent Solution

    Microsoft Academic Search

    Ari Helenius; Kai Simons

    1977-01-01

    Seventeen hydrophilic proteins and five amphiphilic membrane proteins were subjected to agarose gel electrophoresis in the presence of a nonionic detergent (Triton X-100), a mixture of a nonionic and an anionic detergent (Triton X-100 and sodium deoxycholate), and a mixture of a nonionic and a cationic detergent (Triton X-100 and cetyltrimethylammonium bromide). The electrophoretic mobility of the hydrophilic proteins was

  13. Characterization of Carbohydrates Using Highly Fluorescent 2-Aminobenzoic Acid Tag Following Gel Electrophoresis of Glycoproteins

    Microsoft Academic Search

    Kalyan R. Anumula; Ping Du

    1999-01-01

    Application of the most sensitive fluorescent label 2-aminobenzoic acid (anthranilic acid, AA) for characterization of carbohydrates from the glycoproteins (?15 pmol) separated by polyacrylamide gel electrophoresis is described. AA label is used for the determination of both monosaccharide composition and oligosaccharide map. For the monosaccharide determination, bands containing the glycoprotein of interest are excised from the polyvinylidene fluoride (PVDF) membrane

  14. Ulipristal acetate: contraceptive or contragestive?

    PubMed

    Keenan, Jeffrey A

    2011-06-01

    Ulipristal acetate is the first selective progesterone receptor modulator approved for postcoital contraception in the US. It appears to be significantly more effective in inhibition of ovulation than other forms of emergency contraception. However, ulipristal acetate is structurally similar to mifepristone, and several lines of evidence suggest that a postfertilization mechanism of action is also operative. This mechanism of action is considered to be contragestive versus contraceptive. Ulipristal acetate administration is contraindicated in a known or suspected pregnancy; however, it could quite possibly be used as an effective abortifacient. Health-care providers should inform patients of the possibility of both mechanisms of action with use of this drug. PMID:21666088

  15. Molecular Structure of Sodium acetate

    NSDL National Science Digital Library

    2002-08-26

    Sodium acetate is known for its ability to supercool. It freezes at 130 degrees, but can exist as a liquid at a much lower temperature. In order to melt solidified sodium acetate, however, every single crystal must liquify, otherwise the material will recrystallize. Sodium acetate has been used as a deicer for roads and runways. It is also used a component of buffer systems and in the manufacture of pharmaceuticals and heat pads. The compound is quite stable. It may act as an irritant and be harmful if inhaled or absorbed through the skin.

  16. Capillary electrophoresis of alpha-lactalbumin in milk powders.

    PubMed

    Gutierrez, Jose E N; Jakobovits, Lisa

    2003-05-21

    A quick and simple method for the extraction and analysis of alpha-lactalbumin in milk protein powders is presented, which permits accurate duty classification of commercial products as required under the U.S. Harmonized Tariff System. An acetic acid buffer medium is utilized to extract the whey proteins, which are then analyzed by capillary electrophoresis using an electrokinetic injection onto an uncoated column. The running buffer is composed of a 50 mM borate buffer at pH 8.0. The separation is rapid (<5 min) and displays good limits of detection (+/-0.01 mg mL(-1)). Overall, the method provides a simple means for extracting and analyzing alpha-lactalbumin in milk powders. PMID:12744655

  17. Antibiofilm Properties of Acetic Acid

    PubMed Central

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup; Nielsen, Anne K.; Johansen, Helle Krogh; Homøe, Preben; Høiby, Niels; Givskov, Michael; Kirketerp-Møller, Klaus

    2015-01-01

    Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms. PMID:26155378

  18. Methanogenesis from acetate: enrichment studies.

    PubMed

    Baresi, L; Mah, R A; Ward, D M; Kaplan, I R

    1978-07-01

    An acetate enrichment culture was initiated by inoculating anaerobic sludge from a mesophilic methane digestor into a mineral salts medium with calcium acetate as the sole carbon and energy source. This enrichment was maintained indefinitely by weekly transfer into medium of the same composition. A study of this enrichment disclosed an unexpected age-dependent inhibition of methanogenesis by H2 and formate which apparently differed from the inhibition by chloroform and benzyl viologen. This age-dependent inhibition indicated that microbial interactions of the mixed enrichment population may play a regulatory role in methane formation. Futhermore, stimulation of methanogenesis in the acetate enrichment by addition of yeast extract showed a nutrient limitation which indicated that syntrophic interactions leading to formation of growth factors may also occur. A model is presented to illustrate the possible interrelationships between methanogenic and nonmethanogenic bacteria in their growth and formation of methane and carbon dioxide from acetate. PMID:697356

  19. MEMBRANE SURFACE MODIFICATION AND BACKPULSING FOR WASTEWATER TREATMENT

    Microsoft Academic Search

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

    2001-01-01

    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

  20. Molecular Structure of Acetic acid

    NSDL National Science Digital Library

    2003-06-02

    Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

  1. MEMBRANES FORMATION BY SUPERCRITICAL FLUIDS

    Microsoft Academic Search

    E. Reverchon; S. Cardea

    The generation of microporous cellulose acetate and polymethylmethacrylate (PMMA) membranes has been studied using a supercritical fluid based phase inversion process in which CO2 acts as the non-solvent. Some experiments have been performed at 200 bar and 45°C with 20% w\\/w concentration of PMMA in dimethylsulfoxide (DMSO) and with concentrations ranging from 20 to 40% w\\/w of cellulose acetate in

  2. Electromigration dispersion in Capillary Electrophoresis

    PubMed Central

    Chen, Zhen; Ghosal, Sandip

    2012-01-01

    In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010 72, pg. 2047) it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger’s equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data. PMID:22147104

  3. Electromigration dispersion in Capillary Electrophoresis

    E-print Network

    Chen, Zhen; 10.1007/s11538-011-9708-7

    2012-01-01

    In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010, vol. 72, pg. 2047) it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data.

  4. Electromigration dispersion in Capillary Electrophoresis

    E-print Network

    Zhen Chen; Sandip Ghosal

    2012-03-05

    In a previous paper (S. Ghosal and Z. Chen Bull. Math. Biol. 2010, vol. 72, pg. 2047) it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data.

  5. Conducting Polymer Electrodes for Gel Electrophoresis

    PubMed Central

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

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that ?-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation. PMID:24586761

  6. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

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

  7. Putative ABC Transporter Responsible for Acetic Acid Resistance in Acetobacter aceti

    Microsoft Academic Search

    Shigeru Nakano; Masahiro Fukaya; Sueharu Horinouchi

    2006-01-01

    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

  8. Micelles Protect and Concentrate Activated Acetic Acid

    NASA Astrophysics Data System (ADS)

    Todd, Zoe; House, C.

    2014-01-01

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

  9. Biodegradable cellulose acetate nanofiber fabrication via electrospinning.

    PubMed

    Christoforou, Theopisti; Doumanidis, Charalabos

    2010-09-01

    Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

  10. Pre-Cast Gel Electrophoresis Guide

    E-print Network

    Kirschner, Marc W.

    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

  11. Electrophoresis of individual microtubules in microchannels

    E-print Network

    Dekker, Cees

    Electrophoresis of individual microtubules in microchannels M. G. L. van den Heuvel, M. P. de-sized fluidic channels to confine and measure electrophoresis of freely suspended individual microtubules. We measure orientation-dependent velocities of microtubules and the electro-osmotic flow mobility in our

  12. Compensating for Electro-Osmosis in Electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Snyder, Robert S.

    1987-01-01

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

  13. Separation of neutral carbohydrates by capillary electrophoresis

    Microsoft Academic Search

    Susumu Honda

    1996-01-01

    The basic strategies for analysis of neutral carbohydrates by capillary electrophoresis are summarized. Neutral carbohydrates are dissociated in strong alkali to give anions, hence they can be separated directly by zone electrophoresis based on the difference between their dissociation constants. However, neutral carbohydrates are not electrically charged under normal conditions. Therefore, they should be converted to ions prior to or

  14. Elution electrophoresis as a clinical tool

    Microsoft Academic Search

    G. R. Wilkes; R. J. Bertolami; W. M. Choi; P. D. Terpandjian

    1976-01-01

    An experimental investigation of an elution electrophoresis system with a particulate gel packed column was performed. The operating parameters of the apparatus were determined with elution flow studies and electrophoresis migration studies. Flow study results indicated that sample dispersion is dependent on packing type, packing size, elution flow rate, and outlet geometry. Migration studies revealed that sample migration is dependent

  15. Taraxerol acetate at 100 K.

    PubMed

    Billodeaux, D R; Benavides, G A; Fischer, N H; Fronczek, F R

    1999-12-15

    The title triterpene, D-friedoolean-14-en-3 beta-yl acetate, C32H52O2, was isolated from dichloromethane extracts of the roots of common ragweed Ambrosia artemisiifolia. The skeleton contains five fused six-membered rings with an average Csp3-Csp3 bond distance of 1.549 (6) A and one double bond of length 1.348 (6) A. The D and E rings are cis-fused. The compound also contains a beta-oriented acetate group with a C-O distance 1.461 (5) A. PMID:10641284

  16. Nonlinear electrokinetics and "superfast" electrophoresis.

    PubMed

    Ben, Yuxing; Demekhin, Eugene A; Chang, Hsueh-Chia

    2004-08-15

    Nonlinear and nonequilibrium electrophoresis of spherical particles of radius a is shown to be possible when the solid surface allows field or current penetration. At low particle Peclet numbers, transient capacitative charging occurs until the surface polarization completely screens the external field. For a DC applied field [see text], the resulting electrokinetic velocity reaches Dukhin's maximum value of [formula: see text], where [see text] and mu are the liquid permittivity and viscosity. At high Peclet numbers, electroosmotic convection of the electroneutral bulk stops the transient charging before complete field-line exclusion. For an ion-selective and conducting spherical granule, the polarization is then determined by the steady-state Ohmic current driven by the penetrated external field. The high-Peclet electrokinetic velocity is lower, diffusivity-dependent and scales as [see text]. PMID:15271577

  17. Free Solution Electrophoresis of Homopolyelectrolytes

    E-print Network

    Pai-Yi Hsiao; Kun-Mao Wu

    2008-08-22

    We investigate the behavior of single polyelectrolytes in multivalent salt solutions under the action of electric fields through computer simulations. The chain is unfolded in a strong electric field and aligned parallel to the field direction, and the chain size shows a sigmoidal transition. The unfolding electric field $E^*$ depends on the salt concentration and scales as $V^{-1/2}$ with $V$ being the ellipsoidal volume occupied by the chain. The magnitude of the electrophoretic mobility of chain drastically increases during the unfolding. The fact that $E^*$ depends on the chain length provides a plausible mechanism to separate long charged homopolymers by size in free solution electrophoresis via the unfolding transition of globule polyelectrolytes condensed by multivalent salt.

  18. Electrophoresis-mass spectrometry probe

    DOEpatents

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

    1987-11-10

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

  19. Electrophoresis-mass spectrometry probe

    DOEpatents

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

    1987-01-01

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

  20. Dendrimer Electrophoresis in Free Solution

    NASA Astrophysics Data System (ADS)

    Hoagland, David; Welch, Cynthia

    2001-03-01

    Dendrimers possess hydrodynamic sizes in the few nanometer range and well-defined chemical structures intermediate between linear polymer and spherical colloid. By varying the generation, size and structure can be adjusted over limited ranges. Commercially available PPI dendrimers are soluble in water and can be charged at their amine branches and termini by protonation under acidic conditions. All of these properties make dendrimers ideal candidates for testing of theories for electrophoresis. Here, we present data for the dependence of the free solution mobility on dendrimer generation and ionic strength. Unlike linear polymers, mobility changes with molecular weight. In fact, as the generation varies, the mobility changes in the manner of a spherical colloid of equivalent hydrodynamic radius, i.e., data for the dimensionless mobility collapses when plotted against dimensionless size. Variation of mobility with increasing dendrimer ionization is more complicated, as might be expected for a solute of higher surface potential.

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

    E-print Network

    Barker, Marcia Wagner

    1979-01-01

    toxicity, the experiment also strengthened the conviction that the pulmonary pathology occurred by direct contact with oxygen, and was not carried from one lung to the other by the circulatory system. Lung surfactant, a lipoprotein material, coats... of OHP exposure. Barach found that some patients showed disturbances in mental functioning after oxygen exposure. Patients with chronic hypoxemia sometimes went into a deep sleep or stupor, followed by coma and delirium. Comroe, Bahnson and Coates (46...

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

    E-print Network

    Barker, Marcia Wagner

    1979-01-01

    and Grinstein (145) presented data on normal, healthy subjects, on patients with chronic hemolytic anemias and on patients with pernicious anemia given oxygen at concentrations of 50/ at 1 ata. Their findings indicated that HBO at this pO depressed... response observed by Cooperberg and Singer (48). Helvey (78) reported the development of hemolytic anemias in volunteers maintained in simulated space capsule environments using 100% 0 2 at 7. 4 psig for 2 weeks. Osmotic fragilities of red blood cells...

  3. Fragrance material review on 2,4-dimethylbenzyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of 2,4-dimethylbenzyl acetate when used as a fragrance ingredient is presented. 2,4-Dimethylbenzyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, iso-butyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2,4-dimethylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414641

  4. [Conversion of acetic acid to methane by thermophiles]. Annual progress report

    SciTech Connect

    Zinder, S.H.

    1994-02-01

    Acetate is the precursor of approximately two-thirds of the methane produced by anaerobic bioreactors and many other methanogenic habitats. Besides their intrinsic interest, thermophilic acetotrophic methanogenic cultures usually grow at least twice as fast as their mesophilic counterparts, making them more amenable to study. In recent years, attention has been mainly focused on the thermophilic acetate utilizing methanogen Methanothrix strain CALS-1. Methanothrix, also called Methanosaeta, is one of only two methanogenic genera known to convert acetate to methane, the other being Methanosarcina. The faster-growing more versatile Methanosarcina has been better studied. However, when one examines anaerobic digestor contents, Methanothrix is often the dominant acetate-utilizing methanogen. As described in previous progress reports, the authors have achieved methanogenesis from acetate in cell-free extracts of Methanothrix strain CALS-1 grown in a pH auxostat. Using these cell extracts, specific activities for methanogenesis from acetate and ATP of 100--300 nmol/min were routinely obtained, levels comparable to the rate in whole cells, which is not usually the case in methanogenic extracts. Recently obtained results are given and discussed for the following: Methanogenesis in crude extracts; Role of the cell membrane in methanogenesis from acetate; Carbon monoxide dehydrogenase; Novel thermophilic cultures converting acetate to methane; and Methanol-utilizing methanogen.

  5. Ozone decomposition in aqueous acetate solutions

    SciTech Connect

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

    1987-01-01

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

  6. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...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 specifications of the Food...

  7. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...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 specifications of the Food...

  8. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...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 specifications of the Food...

  9. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...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 specifications of the Food...

  10. 21 CFR 184.1721 - Sodium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...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 specifications of the Food...

  11. Electron tunneling studies of Mn12-Acetate 

    E-print Network

    Ma, Lianxi

    2008-10-10

    We used self-assembling tunnel junctions (SATJs) to study the electron transport through films of the molecular magnets, Mn12-Acetate. Pulse laser deposition (PLD) was used to deposit two monolayers of Mn12-Acetate on ...

  12. Concentrating aqueous acetate solutions with tertiary amines 

    E-print Network

    Lee, Champion

    1993-01-01

    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...

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

    NASA Astrophysics Data System (ADS)

    Pielesz, A.

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

  14. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

  15. 21 CFR 73.2396 - Lead acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

  16. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  17. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  18. 27 CFR 21.107 - Ethyl acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

  19. Identification of proteins adsorbed to hemodialyser membranes from heparinized plasma

    Microsoft Academic Search

    Rena M. Cornelius; John L. Brash

    1993-01-01

    The protein layers formed during contact of plasma with hemodialysis membranes were studied. Dialysers having membranes of cellulose acetate (CA), saponified cellulose ester (SCE), cuprophane (CUP), polymethylmethacrylate (PMMA), and polyacrylonitrile (PAN) were used. Heparinized human plasma was recirculated through the dialysers for four hours. They were then rinsed and the proteins adsorbed to the membranes were eluted with 2% SDS.

  20. Membranes for natural gas sweetening and COâ enrichment

    Microsoft Academic Search

    W. H. Mazur; M. C. Chan

    1982-01-01

    Describes how the Gasep membrane, which has been field tested for sweetening natural gas, can also be used for enhanced oil recovery and oxygen enrichment. The cellulose acetate membrane is produced in flat sheet form and to retain its asymmetric character the membrane is heat-treated and dried by proprietary techniques. This produces a highly selective, dense, active layer with a

  1. Mesoscale modelling of polyelectrolyte electrophoresis

    E-print Network

    Kai Grass; Christian Holm

    2009-02-11

    The electrophoretic behaviour of flexible polyelectrolyte chains ranging from single monomers up to long fragments of hundred repeat units is studied by a mesoscopic simulation approach. Abstracting from the atomistic details of the polyelectrolyte and the fluid, a coarse-grained molecular dynamics model connected to a mesoscopic fluid described by the Lattice Boltzmann approach is used to investigate free-solution electrophoresis. Our study demonstrates the importance of hydrodynamic interactions for the electrophoretic motion of polyelectrolytes and quantifies the influence of surrounding ions. The length-dependence of the electrophoretic mobility can be understood by evaluating the scaling behavior of the effective charge and the effective friction. The perfect agreement of our results with experimental measurements shows that all chemical details and fluid structure can be safely neglected, and a suitable coarse-grained approach can yield an accurate description of the physics of the problem, provided that electrostatic and hydrodynamic interactions between all entities in the system, i.e., the polyelectrolyte, dissociated counterions, additional salt and the solvent, are properly accounted for. Our model is able to bridge the single molecule regime of a few nm up to macromolecules with contour lengths of more than 100 nm, a length scale that is currently not accessible to atomistic simulations.

  2. Nonlinear waves in capillary electrophoresis

    PubMed Central

    Ghosal, Sandip; Chen, Zhen

    2011-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis 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

  3. Induced-charge electrophoresis near a wall

    E-print Network

    Kilic, Mustafa Sabri

    Induced-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls in real systems further break symmetry and lead to dielectrophoresis (DEP) in local field ...

  4. High-performance capillary electrophoresis of histones

    SciTech Connect

    Gurley, L.R.; London, J.E.; Valdez, J.G.

    1991-01-01

    A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

  5. Asymmetric cyclopropanation of ketene silyl acetal with allylic acetate catalyzed by a palladium complex

    Microsoft Academic Search

    Akiharu Satake; Hitomi Kadohama; Hiroyuki Koshino; Tadashi Nakata

    1999-01-01

    The first asymmetric cyclopropanation of ketene silyl acetal with allylic acetate was achieved. New chiral oxazolidinylpyrazole ligands and their ?3-allylpalladium complexes were synthesized. Reaction of cinnamyl acetate with ketene silyl acetal of ethyl isobutylate in the presence of a palladium complex gave a phenyl cyclopropane derivative in 20? 54%ee.

  6. Capillary Electrophoresis Applied to Polysaccharide Characterization

    Microsoft Academic Search

    Mila Toppazzini; Anna Coslovi; Sergio Paoletti

    \\u000a Capillary electrophoresis is a consolidated analytical approach for the structural characterization of polysaccharide mono-\\u000a and oligomer constituents, as demonstrated in this chapter, which surveys several applications of this technique on chemically\\u000a and enzymatically degraded polysaccharides, covering the last 10 to 12 years. Capillary electrophoresis is also demonstrated\\u000a to be highly reliable for determination of polysaccharides in biological samples, as it

  7. Affinity Electrophoresis Using Ligands Attached To Polymers

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  8. Free-Flow Open-Chamber Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

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

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

    PubMed

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

    2015-03-01

    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH. PMID:25562466

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

    PubMed

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

    2015-08-01

    Acetic acid inhibits the metabolic activities of Saccharomyces cerevisiae. Therefore, a better understanding of how S. cerevisiae cells acquire the tolerance to acetic acid is of importance to develop robust yeast strains to be used in industry. To do this, we examined the transcriptional changes that occur at 12 h post-exposure to acetic acid, revealing that 56 and 58 genes were upregulated and downregulated, respectively. Functional categorization of them revealed that 22 protein synthesis genes and 14 stress response genes constituted the largest portion of the upregulated and downregulated genes, respectively. To evaluate the association of the regulated genes with acetic acid tolerance, 3 upregulated genes (DBP2, ASC1, and GND1) were selected among 34 non-protein synthesis genes, and 54 viable mutants individually deleted for the downregulated genes were retrieved from the non-essential haploid deletion library. Strains overexpressing ASC1 and GND1 displayed enhanced tolerance to acetic acid, whereas a strain overexpressing DBP2 was sensitive. Fifty of 54 deletion mutants displayed enhanced acetic acid tolerance. Three chosen deletion mutants (hsps82?, ato2?, and ssa3?) were also tolerant to benzoic acid but not propionic and sorbic acids. Moreover, all those five (two overexpressing and three deleted) strains were more efficient in proton efflux and lower in membrane permeability and internal hydrogen peroxide content than controls. Individually or in combination, those physiological changes are likely to contribute at least in part to enhanced acetic acid tolerance. Overall, information of our transcriptional profile was very useful to identify molecular factors associated with acetic acid tolerance. PMID:26062532

  11. Simultaneous production of immunoaffinity membranes.

    PubMed

    Shimazaki, Youji; Miyamoto, Masayuki

    2010-10-15

    We simultaneously separated antibodies for transferrin, the third component of complement (C3), haptoglobin and transthyretin by multi-sample non-denaturing two-dimensional electrophoresis (2-DE), transferred them to a polyvinylidene difluoride (PVDF) membrane and then stained them using direct blue 71 to obtain membrane-immobilized antibodies. The antigens, transferrin, C3, haptoglobin and transthyretin were specifically bound to the membrane-immobilized antibodies and were eluted only after rinsing the membrane with acid solution. The antigens specifically bound to the membrane-immobilized antibodies were separated by SDS-PAGE and identified by peptide mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Furthermore, transferrin and transthyretin were trapped and eluted by each membrane-immobilized antibody and detected by MALDI-TOF MS directly without separations. Using membrane-immobilized anti-transferrin antibody, transferrin in flowing blood was directly trapped and analyzed. The results indicated that membrane-immobilized antibodies are simultaneously produced, and that the immunoaffinity membranes can capture specific substances in flowing fluids. PMID:20851694

  12. Membrane controlled anaerobic digestion

    NASA Astrophysics Data System (ADS)

    Omstead, D. R.

    In response to general shortages of energy, examination of the anaerboic digestion process as a potential source of a combustible, methane-rich fuel has intensified in recent years. It has been suggested that orgaic intermediates (such as fatty acids), produced during digestion, might also be recovered for use as chemical feedstocks. This investigation has been concerned with combining ultrafiltration separation techniques with anaerobic digestion for the development of a process in which the total production of acetic acid (the most valuable intermediate in anaerobic digestion) and methane are optimized. Enrichment cultures, able to utilize glucose as a sole carbon source, were adapted from sewage digesting cultures using conventional techniques. An ultrafiltration system was constructed and coupled to an anaerobic digester culture vessel which contained the glucose enrichment. The membrane controlled anaerobic digester appears to show promise as a means of producing high rates of both methane gas and acetic acid.

  13. Nonwoven fabric supported poly(acrylonitrile-vinyl acetate) gel electrolyte for lithium ion battery use

    Microsoft Academic Search

    Xiaoping Li; Mumin Rao; Youhao Liao; Weishan Li; Mengqing Xu

    2010-01-01

    This paper reported on a new gel polymer electrolyte (GPE) based on polyethylene (PE) non-woven fabric supported poly(acrylonitrile-vinyl\\u000a acetate) (P(AN-VAc)\\/PE) membrane for lithium ion battery use. The preparation and performances of the P(AN-VAc)\\/PE membrane\\u000a and its GPE based on 1 M LiPF6 in dimethyl carbonate\\/diethylene carbonate\\/ethylene carbonate (1:1:1 in volume) were investigated with a comparison of the\\u000a unsupported P(AN-VAc) membrane. It

  14. Aurantiamide acetate suppresses the growth of malignant gliomas in vitro and in vivo by inhibiting autophagic flux

    PubMed Central

    Yang, Yi; Zhang, Li-hui; Yang, Bing-xian; Tian, Jin-kui; Zhang, Lin

    2015-01-01

    We aim to investigate the effect of aurantiamide acetate isolated from the aerial parts of Clematis terniflora DC against gliomas. Human malignant glioma U87 and U251 cells were incubated with different concentrations (0–100 ?M) of aurantiamide acetate. Aurantiamide acetate greatly decreased the cell viability in a dose- and time-dependent manner. It induced moderate mitochondrial fragmentation and the loss of mitochondrial membrane potential. No significant difference was found in the alternation of other intracellular organelles, although F-actin structure was slightly disturbed. Apparent ultrastructure alternation with increased autophagosome and autolysosome accumulation was observed in aurantiamide acetate-treated cells. The expression of LC3-II was greatly up-regulated in cells exposed to aurantiamide acetate (P < 0.05 compared with control). The cytoplasmic accumulation of autophagosomes and autolysosomes induced by aurantiamide acetate treatment was confirmed by fluorescent reporter protein labelling. Administration of chloroquine (CQ), which inhibits the fusion step of autophagosomes, further increased the accumulation of autophagosomes in the cytoplasm of U87 cells. Autophagy inhibition by 3-methyladenine, Bafilomycin A1 or CQ had no influence on aurantiamide acetate-induced cytotoxicity, whereas autophagy stimulator rapamycin significantly suppressed aurantiamide acetate-induced cell death. The anti-tumour effects of aurantiamide acetate were further evaluated in tumour-bearing nude mice. Intratumoural injection of aurantiamide acetate obviously suppressed tumour growth, and increased number of autophagic vacuoles was observed in tumour tissues of animals receiving aurantiamide acetate. Our findings suggest that aurantiamide acetate may suppress the growth of malignant gliomas by blocking autophagic flux. PMID:25704599

  15. SOLID-PHASE ASSAY FOR THE PHOSPHORYLATION OF PROTEINS BLOTTED ON NITROCELLULOSE MEMBRANE FILTERS

    EPA Science Inventory

    A new procedure for the phosphorylation and assay of phosphoproteins is described. Proteins are solubilized from tissue samples, separated by polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane filters and the blotted polypeptides are phosphorylated with ...

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

    PubMed

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

    2013-07-01

    Hereditary spherocytosis and elliptocytosis are the two most common inherited red cell membrane disorders resulting from mutations in genes encoding various red cell membrane and skeletal proteins. Red cell membrane, a composite structure composed of lipid bilayer linked to spectrin-based membrane skeleton is responsible for the unique features of flexibility and mechanical stability of the cell. Defects in various proteins involved in linking the lipid bilayer to membrane skeleton result in loss in membrane cohesion leading to surface area loss and hereditary spherocytosis while defects in proteins involved in lateral interactions of the spectrin-based skeleton lead to decreased mechanical stability, membrane fragmentation and hereditary elliptocytosis. The disease severity is primarily dependent on the extent of membrane surface area loss. Both these diseases can be readily diagnosed by various laboratory approaches that include red blood cell cytology, flow cytometry, ektacytometry, electrophoresis of the red cell membrane proteins, and mutational analysis of gene encoding red cell membrane proteins. PMID:23664421

  17. Application of Microchip Electrophoresis for Clinical Tests

    NASA Astrophysics Data System (ADS)

    Yatsushiro, Shouki; Kataoka, Masatoshi

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

  18. Solid-phase extraction and sample stacking-capillary electrophoresis for the determination of quaternary ammonium herbicides in drinking water.

    PubMed

    Núñez, O; Moyano, E; Galceran, M T

    2002-02-01

    Conditions for the simultaneous determination of paraquat, diquat and difenzoquat by capillary zone electrophoresis were established by combining two preconcentration procedures. Off-line solid-phase extraction was used for the isolation and preconcentration of quats in drinking water. Quats were then analysed by capillary electrophoresis using sample stacking with matrix removal as on-column preconcentration procedure. Two different porous graphitic carbon cartridges were compared. The breakthrough volumes of the three herbicides were calculated and the loading capacity of the sorbents was compared. Recoveries higher than 80% for difenzoquat and around 40% for paraquat and diquat were obtained when a sample volume of 250 ml was percolated. For the stacking-capillary electrophoresis analysis of quats, 50 mM acetic acid-ammonium acetate (pH 4.0), 0.8 mM cetyltrimethylammonium bromide with 5% (v/v) methanol as carrier electrolyte was used. Detection limits, based on a signal-to-noise ratio of 3:1, were lower than 0.3 microg l(-1) for standards in Milli-Q water, and lower than 2.2 microg l(-1) for drinking water samples. Run-to-run and day-to-day precision of the method were established. The two preconcentration procedures used together was successfully applied to the analysis of the three herbicides in spiked drinking water at concentrations below the maximum admissible US Environmental Protection Agency levels. PMID:11873975

  19. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...reporting. (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  20. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  1. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  2. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  3. 40 CFR 721.10001 - 2-Ethoxyethanol, 2-ethoxyethanol acetate, 2-methoxyethanol, and 2-methoxyethanol acetate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...reporting . (1) The chemical substances identified as 2-ethoxyethanol (CAS No. 110-80-5), 2-ethoxyethanol acetate (CAS No. 111-15-9), 2-methoxyethanol (CAS No. 109-86-4), and 2-methoxyethanol acetate (CAS No....

  4. BIOCHEMICAL AND MORPHOLOGICAL COMPARISON OF PLASMA MEMBRANE AND MILK FAT GLOBULE MEMBRANE FROM BOVINE MAMMARY GLAND

    PubMed Central

    Keenan, T. W.; Morré, D. James; Olson, Diane E.; Yunghans, W. N.; Patton, Stuart

    1970-01-01

    Purified plasma membrane fractions from lactating bovine mammary glands and membranes of milk fat globules from the same source were similar in distribution and fatty acid composition of phospholipids. The sphingomyelin content of the phospholipid fraction of both membranes was higher than in these fractions from other cell components, ?-carotene, a constituent characteristic of milk fat, was present in the lipid fraction of the plasma membrane. Cholesterol esters of plasma membrane were similar in fatty acid composition to those of milk fat globule membranes. Disc electrophoresis of either membrane preparation on polyacrylamide gels revealed a single major protein component characteristic of plasma membrane from other sources. Distinct morphological differences between plasma membrane and milk fat globule membranes were observed in both thin sections and in negatively stained material. Plasma membrane was vesicular in appearance while milk fat globule membranes had a platelike aspect. These observations are consistent with derivation of fat globule membrane from plasma membrane accompanied by structural rearrangement of membrane constituents. PMID:5409465

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

    PubMed

    Adler, Heidi; Sirén, Heli

    2014-01-01

    The research was performed to study the simultaneous detection of a homologous series of ? , ? -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

  6. Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

    PubMed Central

    Adler, Heidi; Sirén, Heli

    2014-01-01

    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/m3. PMID:24729915

  7. Positron scattering from vinyl acetate

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  8. Fungal degradation of polyvinyl acetate.

    PubMed

    García Trejo, A

    1988-08-01

    Certain Aspergillus and Penicillium strains isolated from soil grow well and degrade a commercial sample of polyvinyl acetate (PVA, 4.5 g liter-1) when it is used as the only carbon source. These strains showed an increase in dry weight after 11 days of incubation, along with a depletion of carbohydrates, protein, and deoxyribonucleic acid. This was interpreted as an active turnover of the above metabolites during the degradation. This effect was greatly enhanced by equilibrating the carbon:nitrogen ratio by addition of yeast extract in the original culture. The increase in esterase activity and the loss of viscosity were also considered evidence of the fungal degradation. Isolation of the enzyme was attempted, but unsuccessful. PMID:3181066

  9. Gel Electrophoresis on a Budget to Dye For

    NSDL National Science Digital Library

    Julie H. Yu

    2010-01-01

    Gel electrophoresis is one of the most important tools used in molecular biology and has facilitated the entire field of genetic engineering by enabling the separation of nucleic acids and proteins. However, commercial electrophoresis kits can cost up to

  10. Electrophoresis 2014, 35, 721727 721 Akshay Kale1

    E-print Network

    Xuan, Xiangchun "Schwann"

    Electrophoresis 2014, 35, 721­727 721 Akshay Kale1 Saurin Patel1 Shizhi Qian2 Guoqing Hu3 Xiangchun electrophoresis while has a weak impact on the particle velocity due to rDEP. The numerical predictions

  11. Electrophoresis 2013, 34, 961968 961 Saurin Patel1

    E-print Network

    Xuan, Xiangchun "Schwann"

    Electrophoresis 2013, 34, 961­968 961 Saurin Patel1 Shizhi Qian2,3 Xiangchun Xuan1 1Department of unequal velocities [27], respectively. Free-flow electrophoresis is a continuous-flow approach [28], where

  12. Protein Charge Ladders, Capillary Electrophoresis, and

    E-print Network

    Prentiss, Mara

    Protein Charge Ladders, Capillary Electrophoresis, and the Role of Electrostatics in Biomolecular Introduction Life rests on a web of molecular recognition;1,2 the folding of proteins, the hybridization the recognition site of the protein. Hydrophobic interactions, although still a challenge to describe

  13. A Simple Vertical Slab Gel Electrophoresis Apparatus.

    ERIC Educational Resources Information Center

    Carter, J. B.; And Others

    1983-01-01

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

  14. Increasing Sensitivity In Continuous-Flow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

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

  15. Mesoscopic simulations of polyelectrolyte electrophoresis in nanochannels

    E-print Network

    Smiatek, Jens

    2010-01-01

    We present the results of mesoscopic dissipative particle dynamics (DPD) simulations of coupled electrohydrodynamic phenomena on the micro- and nanoscale. The effects of electroosmotic flow and slippage combined with polyelectrolyte electrophoresis are investigated in detail, taking full account of hydrodynamic and electrostatic interactions. Our numerical results are in excellent agreement with analytical calculations.

  16. Mesoscopic simulations of polyelectrolyte electrophoresis in nanochannels

    E-print Network

    Jens Smiatek; Friederike Schmid

    2010-07-21

    We present the results of mesoscopic dissipative particle dynamics (DPD) simulations of coupled electrohydrodynamic phenomena on the micro- and nanoscale. The effects of electroosmotic flow and slippage combined with polyelectrolyte electrophoresis are investigated in detail, taking full account of hydrodynamic and electrostatic interactions. Our numerical results are in excellent agreement with analytical calculations.

  17. 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.

  18. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SciTech Connect

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

    2004-03-24

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

  19. Role of gravity in preparative electrophoresis

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1975-01-01

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

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

    PubMed Central

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

    2008-01-01

    Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO2 loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels. PMID:18502856

  1. A specialized citric acid cycle requiring succinyl-coenzyme A (CoA):acetate CoA-transferase (AarC) confers acetic acid resistance on the acidophile Acetobacter aceti.

    PubMed

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

    2008-07-01

    Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO(2) loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels. PMID:18502856

  2. Manufacturing Ethyl Acetate From Fermentation Ethanol

    NASA Technical Reports Server (NTRS)

    Rohatgi, Naresh K.; Ingham, John D.

    1991-01-01

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

  3. Cellulose Acetate-Poly(N-isopropylacrylamide)-Based Functional Surfaces with Temperature-Triggered Switchable Wettability.

    PubMed

    Ganesh, V Anand; Ranganath, Anupama Sargur; Sridhar, Radhakrishnan; Raut, Hemant Kumar; Jayaraman, Sundaramurthy; Sahay, Rahul; Ramakrishna, Seeram; Baji, Avinash

    2015-07-01

    Temperature-triggered switchable nanofibrous membranes are successfully fabricated from a mixture of cellulose acetate (CA) and poly(N-isopropylacrylamide) (PNIPAM) by employing a single-step direct electrospinning process. These hybrid CA-PNIPAM membranes demonstrate the ability to switch between two wetting states viz. superhydrophilic to highly hydrophobic states upon increasing the temperature. At room temperature (23 °C) CA-PNIPAM nanofibrous membranes exhibit superhydrophilicity, while at elevated temperature (40 °C) the membranes demonstrate hydrophobicity with a static water contact angle greater than 130°. Furthermore, the results here demonstrate that the degree of hydrophobicity of the membranes can be controlled by adjusting the ratio of PNIPAM in the CA-PNIPAM mixture. PMID:25965973

  4. Electrophoresis 2012, 33, 599606 599 Rossella Gottardo1

    E-print Network

    Miksik, Ivan

    Electrophoresis 2012, 33, 599­606 599 Rossella Gottardo1 Ivan Miks´ik2 Zeineb Aturki3 Daniela Sorio Article Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization

  5. Noncovalent Polycationic Coatings for Capillaries in Capillary Electrophoresis of Proteins

    E-print Network

    Gao, Jinming

    Noncovalent Polycationic Coatings for Capillaries in Capillary Electrophoresis of Proteins Emilio-silica capillaries is a common problem in the analysis of proteins by capillary electrophoresis.1-3 The walls is important in extending the utility of capillary electrophoresis to a broader range of proteins

  6. Contour Area Filtering of 2-Dimensional Electrophoresis Images

    E-print Network

    Wenger, Rephael

    1 Contour Area Filtering of 2-Dimensional Electrophoresis Images PRamakrishnan Kazhiyur-Mannar,1 was designed specifically for image analysis of 2D electrophoresis gels, although it can be applied to other results which show that Contour Area Filtering is a quick, efficient method for separating electrophoresis

  7. Capillary Electrophoresis-Electrospray Mass Spectrometry for the Characterization of

    E-print Network

    Tian, Weidong

    Capillary Electrophoresis-Electrospray Mass Spectrometry for the Characterization of High-glycosylation by capillary electrophoresis-electrospray mass spectrom- etry (CE-ESI MS) was described. In addition to the use, methodologies for resolving glycoforms by capillary electrophoresis (CE) were developing rapidly by using basic

  8. Properties of Multivariate Binding Isotherms in Capillary Electrophoresis

    E-print Network

    Chen, David D.Y.

    Properties of Multivariate Binding Isotherms in Capillary Electrophoresis Michael T. Bowser, Andrea, BC, Canada V6T 1Z1 When more than one complexation additive is used in capillary electrophoresis (CE in capillary electrophoresis (CE) has increased dramati- cally in recent years. Terabe et al. were the first

  9. Chapter 2 Chip Capillary Electrophoresis and Total Genetic Analysis Systems

    Microsoft Academic Search

    Qiang Xiong; Jing Cheng

    2007-01-01

    The utilization of new sequencing techniques based on capillary array electrophoresis (CAE) has had a great impact on the progress of the Human Genome Project (HGP), and finally led to its successful completion at much lower costs than initially anticipated for the project (Collins et al., 2003). Similarly, chip-based capillary electrophoresis, the technological extension of capillary electrophoresis (CE), is a

  10. A Review of Analysis of Pesticides Using Capillary Electrophoresis

    Microsoft Academic Search

    Ashok Kumar Malik; Werner Faubel

    2001-01-01

    Capillary electrophoresis is a micro volume separation technique increasingly achieving recognition for use in the separation and determination of pesticides due to its relatively short analysis time, and nano liter to picoliter sample volumes. Capillary electrophoresis is attracting considerable attention from many laboratories due to its simplicity. This overview discusses the applications of capillary electrophoresis for trace detection and determination

  11. Protein Electrophoresis in the Biology Classroom Using "Safe" Gels.

    ERIC Educational Resources Information Center

    Atkins, Thomas

    1991-01-01

    Describes the use of electrophoresis in the high school utilizing two new gels that are easy to pour, do not require degassing, can be used on a horizontal gel electrophoresis, and are not neurotoxic or carcinogenic health hazards. Large diagrams and written instructions are used to present the protocol of setting up the electrophoresis. (PR)

  12. Membrane stabilizer

    DOEpatents

    Mingenbach, William A. (P.O. Box 49, Taos, NM 87571)

    1988-01-01

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

  13. exchange membranes

    Microsoft Academic Search

    W. Michaels; J. Vermeulen; R. D. Sanderson; D. G. Bessarabov

    The chemical modification of the surface of ion-exchange membranes (SPE, solid polymer electrolytes) provides new possibilities for applications of SPE-based membrane catalytic systems (1). Surface modification can considerably influence the surface properties of the membrane. In the case of catalyst deposition on the modified membrane, the profile of the catalyst particles within the membrane and their size can be alternated

  14. CHLOROPLAST STRUCTURE AND FUNCTION IN ac-20, A MUTANT STRAIN OF CHLAMYDOMONAS REINHARDI: III. Chloroplast Ribosomes and Membrane Organization

    Microsoft Academic Search

    URSULA W. GOODENOUGH; R. P. LEVINE

    1970-01-01

    The fine structure of the ac-20strain of Chlamydomonas reinhardi is described . Cells grown mixotrophically in the presence of acetate have a highly disordered chloroplast membrane organization and usually lack pyrenoids . Chloroplast ribosome levels are only 5-10% of wild-type levels . Cells grown phototrophically without acetate possess more chloroplast ribosomes and have more normal membrane and pyrenoid organization .Chloroplast

  15. Lipidomic Profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii Reveals Critical Changes in Lipid Composition in Response to Acetic Acid Stress

    PubMed Central

    Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

    2013-01-01

    When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L?1, while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L?1 acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large rearrangements in its lipid profile. PMID:24023914

  16. Automated extraction of direct, reactive, and vat dyes from cellulosic fibers for forensic analysis by capillary electrophoresis.

    PubMed

    Dockery, C R; Stefan, A R; Nieuwland, A A; Roberson, S N; Baguley, B M; Hendrix, J E; Morgan, S L

    2009-08-01

    Systematic designed experiments were employed to find the optimum conditions for extraction of direct, reactive, and vat dyes from cotton fibers prior to forensic characterization. Automated microextractions were coupled with measurements of extraction efficiencies on a microplate reader UV-visible spectrophotometer to enable rapid screening of extraction efficiency as a function of solvent composition. Solvent extraction conditions were also developed to be compatible with subsequent forensic characterization of extracted dyes by capillary electrophoresis with UV-visible diode array detection. The capillary electrophoresis electrolyte successfully used in this work consists of 5 mM ammonium acetate in 40:60 acetonitrile-water at pH 9.3, with the addition of sodium dithionite reducing agent to facilitate analysis of vat dyes. The ultimate goal of these research efforts is enhanced discrimination of trace fiber evidence by analysis of extracted dyes. PMID:19536528

  17. Changes in Phospholipid Composition Studied by HPLC and Electric Properties of Liver Cell Membrane of Ethanol-Poisoned Rats

    PubMed Central

    Szachowicz-Petelska, Barbara; Dobrzy?ska, Izabela; Skrzydlewska, El?bieta; Figaszewski, Zbigniew A.

    2008-01-01

    Ethanol introduced into the organism undergoes rapid metabolism to acetaldehyde and then to acetic acid. The process is accompanied by formation of reactive oxygen species (ROS), which damage mainly lipids of membrane cells. The effects of ROS can be neutralized by administering preparations with antioxidant properties. The natural preparations of this kind are teas. This paper reports data on the effect of green and black tea on the surface charge density, content of phospholipids, and level of lipid peroxidation products of liver cell membrane of rats chronically intoxicated with ethanol. Surface charge density of liver cells was measured by the electrophoresis method, whereas qualitative phospholipid composition was determined by the HPLC method. Ethanol administration caused an increase in the amount of all phospholipids, in surface charge density as well as in lipid peroxidation products. Ingestion of green and black tea with ethanol partially prevented these ethanol-induced changes, and the action of green tea was stronger than that of black tea. PMID:19696939

  18. Changes in Phospholipid Composition Studied by HPLC and Electric Properties of Liver Cell Membrane of Ethanol-Poisoned Rats.

    PubMed

    Szachowicz-Petelska, Barbara; Dobrzy?ska, Izabela; Skrzydlewska, El?bieta; Figaszewski, Zbigniew A

    2008-07-01

    Ethanol introduced into the organism undergoes rapid metabolism to acetaldehyde and then to acetic acid. The process is accompanied by formation of reactive oxygen species (ROS), which damage mainly lipids of membrane cells. The effects of ROS can be neutralized by administering preparations with antioxidant properties. The natural preparations of this kind are teas.This paper reports data on the effect of green and black tea on the surface charge density, content of phospholipids, and level of lipid peroxidation products of liver cell membrane of rats chronically intoxicated with ethanol. Surface charge density of liver cells was measured by the electrophoresis method, whereas qualitative phospholipid composition was determined by the HPLC method.Ethanol administration caused an increase in the amount of all phospholipids, in surface charge density as well as in lipid peroxidation products. Ingestion of green and black tea with ethanol partially prevented these ethanol-induced changes, and the action of green tea was stronger than that of black tea. PMID:19696939

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

    DOEpatents

    Zhang, Jian-Shi (Shanghai, CN); Giometti, Carol S. (Glenview, IL); Tollaksen, Sandra L. (Montgomery, IL)

    1989-01-01

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

  20. Ulipristal acetate in emergency contraception.

    PubMed

    Goldstajn, Marina Sprem; Baldani, Dinka Pavici?; Skrgati?, Lana; Radakovi?, Branko; Vrbi?, Hrvoje; Cani?, Tomislav

    2014-03-01

    Despite the widespread availability of highly effective methods of contraception, unintended pregnancy is common. Unplanned pregnancies have been linked to a range of health, social and economic consequences. Emergency contraception reduces risk of pregnancy after unprotected intercourse, and represents an opportunity to decrease number of unplanned pregnancies and abortions. Emergency contraception pills (ECP) prevent pregnancy by delaying or inhibiting ovulation, without interfering with post fertilization events. If pregnancy has already occurred, ECPs will not be effective, therefore ECPs are not abortificants. Ulipristal acetate (17alpha-acetoxy-11beta-(4N-N,N-dymethilaminophenyl)-19-norpregna--4,9-diene-3,20-dione) is the first drug that was specifically developed and licensed for use as an emergency contraceptive. It is an orally active, synthetic, selective progesterone modulator that acts by binding with high affinity to the human progesterone receptor where it has both antagonist and partial agonist effects. It is a new molecular entity and the first compound in a new pharmacological class defined by the pristal stem. Up on the superior clinical efficacy evidence, UPA has been quickly recognized as the most effective emergency contraceptive pill, and recently recommended as the first prescription choice for all women regardless of the age and timing after intercourse. This article provides literature review of UPA and its role in emergency contraception. PMID:24851646

  1. Modification of membrane surface for anti-biofouling performance: Effect of anti-adhesion and anti-bacteria approaches

    Microsoft Academic Search

    C. X. Liu; D. R. Zhang; Yi He; X. S. Zhao; Renbi Bai

    2010-01-01

    Membrane biofouling refers to the undesirable accumulation (attachment and growth) of microorganisms on a membrane surface, and has been a major problem in the application of membrane technology in water and wastewater treatment. In this study, the surface of a base membrane made of chitosan\\/cellulose acetate blend was modified by reacting with heparin, quaternary ammonium or being immobilized with silver

  2. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  3. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  4. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  5. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  6. 21 CFR 582.5933 - Vitamin A acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

  7. Membrane Extraction for Detoxification of Biomass Hydrolysates

    Microsoft Academic Search

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

    2012-01-01

    Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol. Rapid removal of sulfuric acid, 5-hydroxymethyl and furfural was observed.

  8. Doped with Sodium Acetate and Metallic Sodium

    NASA Astrophysics Data System (ADS)

    Tada, Satoki; Isoda, Yukihiro; Udono, Haruhiko; Fujiu, Hirofumi; Kumagai, Shunji; Shinohara, Yoshikazu

    2014-06-01

    We have investigated the thermoelectric properties of p-type Na-doped Mg2 Si0.25Sn0.75 solid solutions prepared by liquid-solid reaction and hot-pressing methods. Na was introduced into Mg2Si0.25Sn0.75 by using either sodium acetate (CH3COONa) or metallic sodium (2 N). The samples doped with sodium acetate consisted of phases with antifluorite structure and a small amount of MgO as revealed by x-ray diffraction, whereas the sample doped with metallic sodium contained the Sn, MgO, and Mg2SiSn phases. The hole concentrations of Mg1.975Na0.025Si0.25Sn0.75 doped by sodium acetate and metallic sodium were 1.84 × 1025 m-3 and 1.22 × 1025 m-3, respectively, resulting in resistivities of 4.96 × 10-5 ? m (sodium acetate) and 1.09 × 10-5 ? m (metallic sodium). The Seebeck coefficients were 198 ?V K-1 (sodium acetate) and 241 ?V K-1 (metallic sodium). The figures of merit for Mg1.975Na0.025Si0.25Sn0.75 were 0.40 × 10-3 K-1 (sodium acetate) and 0.25 × 10-3 K-1 (metallic sodium) at 400 K. Thus, sodium acetate is a suitable Na dopant for Mg2Si1- x Sn x .

  9. Membrane-based air separation for catalytic oxidation of isolongifolene

    Microsoft Academic Search

    Fawen Wu; Zhihong Xu; Zhixiang Wang; Yiqiang Shi; Lei Li; Zhibing Zhang

    2010-01-01

    Oxygen-enriched air (OEA) from membrane-based air separation has been widely used in the industrial field in the past two decades. Isolongifolenone, an oxygenated derivative of isolongifolene, is an important perfume ingredient in the perfumery industry. In this paper, the OEA produced by the membranes was employed as oxidant to convert isolongifolene into isolongifolenone with cobaltous acetate as catalyst. The effects

  10. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Ghosal, Sandip

    2006-01-01

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

  11. Mathematical Models of Continuous Flow Electrophoresis

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  12. A new approach to electrophoresis in space

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S.; Rhodes, Percy H.

    1990-01-01

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

  13. Application of capillary electrophoresis in glycoprotein analysis.

    PubMed

    Rustandi, Richard R; Anderson, Carrie; Hamm, Melissa

    2013-01-01

    Capillary electrophoresis (CE) is a versatile analytical method used to characterize glycoproteins. We have used several modes of CE separation such as CE-SDS gel, imaged capillary isoelectric focusing (icIEF), and capillary zone electrophoresis (CZE) to study therapeutic glycoprotein products. CE-SDS gel is applied to characterize the glycan occupancy and number of glycosylation sites, and icIEF is used to study the charge heterogeneities due to sialic acids in glycoproteins. To further characterize the glycoprotein, removal of N-linked glycans is necessary and a CZE technique is employed to analyze each glycan moiety. Examples from a monoclonal antibody, erythropoietin, and granulocyte colony-stimulating factor are presented here to demonstrate the utility of these CE modes. The details of sample preparation and separation conditions for each CE mode are described in this chapter. PMID:23475720

  14. Capillary Zone Electrophoresis–Electrospray Ionization-Tandem Mass Spectrometry for Top-Down Characterization of the Mycobacterium marinum Secretome

    PubMed Central

    2015-01-01

    Capillary zone electrophoresis (CZE) with an electrokinetically pumped sheath-flow nanospray interface was coupled with a high-resolution Q-Exactive mass spectrometer for the analysis of culture filtrates from Mycobacterium marinum. We confidently identified 22 gene products from the wildtype M. marinum secretome in a single CZE–tandem mass spectrometry (MS/MS) run. A total of 58 proteoforms were observed with post-translational modifications including signal peptide removal, N-terminal methionine excision, and acetylation. The conductivities of aqueous acetic acid and formic acid solutions were measured from 0.1% to 100% concentration (v/v). Acetic acid (70%) provided lower conductivity than 0.25% formic acid and was evaluated as low ionic-strength and a CZE–MS compatible sample buffer with good protein solubility. PMID:24725189

  15. Method and apparatus for continuous electrophoresis

    SciTech Connect

    Watson, Jack S. (Knoxville, TN)

    1992-01-01

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

  16. DNA sequencing using capillary array electrophoresis

    Microsoft Academic Search

    Xiaohua C. Huang; Mark A. Quesada; Richard A. Mathies

    1992-01-01

    A DNA sequencing method is presented that utilizes capillary array electrophoresis, two-color fluorescence detection, and a two-dye labeling protocol. Sanger DNA sequencing fragments are separated on an array of capillaries and detected on-column using a two-color, laser-excited, confocal-fluorescence scanner. The four set of DNA sequencing fragments are separated in a single capillary and then distinguished by using a binary coding

  17. Commander prepares glass columns for electrophoresis experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

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

  18. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D`Silva, A.

    1996-08-06

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

  19. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1994-06-28

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

  20. Hemoglobin Electrophoresis and Hemoglobinopathies in Kuwait

    Microsoft Academic Search

    R. Marouf; T. M. D’souza; A. D. Adekile

    2002-01-01

    Objectives: To analyze the results of hemoglobin electrophoresis (HE) in the routine laboratory of a tertiary hospital in Kuwait and to review the common types of hemoglobinopathies prevalent in the country. Methods: This was a prospective study of HE performed on 2,386 samples in Mubarak Al-Kabeer Hospital, which serves more than 30% of the population of Kuwait, from June 1997

  1. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

    1996-03-12

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

  2. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1996-03-12

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

  3. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

    1994-06-28

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

  4. Stripping Potentiometry of Lead, Cadmium and Copper at a Nafion Coated Glassy Carbon Electrode with Encapsulated Mercury Acetate

    Microsoft Academic Search

    Carlo Maccà; Mark Bradshaw; Arben Merkoci; Geoffrey Scollary

    1997-01-01

    The stripping potentiometric determination of lead, cadmium and copper with mercury film glassy-carbon electrodes coated with a Nafion membrane was investigated. The mercury film was plated using either mercury(II) acetate encapsulated within the Nafion membrane or a mercury(II) solution. Dissolved dioxygen was used as the stripping agent. The electrodes showed promising properties, particularly robustness and response repeatability. A linear dependence

  5. Detection of telomerase activity using microchip electrophoresis.

    PubMed

    Karasawa, Koji; Arakawa, Hidetoshi

    2015-07-01

    Telomerase participates in malignant transformation or immortalization of cells and thus has attracted attention as an anticancer drug target and diagnostic tumor marker. The telomeric repeat amplification protocol (TRAP) and improved TRAP methods (TRAP-fluorescence, TRAP-hybridization, etc.) are widely used forms of this telomerase assay. However, these approaches generally employ acrylamide gel electrophoresis after amplification of telomeric repeats by polymerase chain reaction (PCR), making these TRAP methods time consuming and technically demanding. In this study we developed a novel telomerase assay using microchip electrophoresis for rapid and highly sensitive detection of telomerase activity in cancer cells. The mixed gel of 0.8% hydroxypropyl methylcellulose (HPMC) and 0.3% polyethylene oxide (PEO) with SYBR Gold (fluorescent reagent) was used for microchip electrophoresis. As a result, the product amplified by a telomerase-positive cell could be measured in one cell per assay and detected with high reproducibility (CV=0.67%) in the short time of 100s. PMID:25980765

  6. Rapid analytical and preparative isolation of functional endosomes by free flow electrophoresis

    PubMed Central

    1987-01-01

    Endosomes are prelysosomal organelles that serve as an intracellular site for the sorting, distribution, and processing of receptors, ligands, fluid phase components, and membrane proteins internalized by endocytosis. Whereas the overall functions of endosomes are increasingly understood, little is known about endosome structure, composition, or biogenesis. In this paper, we describe a rapid procedure that permits analytical and preparative isolation of endosomes from a variety of tissue culture cells. The procedure relies on a combination of density gradient centrifugation and free flow electrophoresis. It yields a fraction of highly purified, functionally intact organelles. As markers for endosomes in Chinese hamster ovary cells, we used endocytosed horseradish peroxidase, FITC-conjugated dextran, and [35S]methionine-labeled Semliki Forest virus. Total postnuclear supernatants, crude microsomal pellets, or partially purified Golgi fractions were subjected to free flow electrophoresis. Endosomes and lysosomes migrated together as a single anodally deflected peak separated from most other organelles (plasma membrane, mitochondria, endoplasmic reticulum, and Golgi). The endosomes and lysosomes were then resolved by centrifugation in Percoll density gradients. Endosomes prepared in this way were enriched up to 70-fold relative to the initial homogenate and were still capable of ATP- dependent acidification. By electron microscopy, the isolated organelles were found to consist of electron lucent vacuoles and tubules, many of which could be shown to contain an endocytic tracer (e.g., horseradish peroxidase). SDS PAGE analysis of integral and peripheral membrane proteins (separated from each other by condensation in Triton X-114) revealed a unique and restricted subset of proteins when compared with lysosomes, the unshifted free flow electrophoresis peak, and total cell protein. Altogether, the purification procedure takes 5-6 h and yields amounts of endosomes (150-200 micrograms protein) sufficient for biochemical, immunological, and functional analysis. PMID:3031085

  7. Acetic Acid Off Gassing in Clamshell Enclosures

    E-print Network

    Brewer, Allison

    2013-01-01

    . This presentation will investigate the use of acid detection strips (A-D strips) to study acetic acid off gassing occurring in custom-made, cloth covered book boxes constructed and used by conservators in research libraries....

  8. Fragrance material review on 4-methylbenzyl acetate.

    PubMed

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

    2012-09-01

    A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414643

  9. Methanogenesis from acetate: a nonmethanogenic bacterium from an anaerobic acetate enrichment.

    PubMed

    Ward, D M; Mah, R A; Kaplan, I R

    1978-06-01

    A methanogenic acetate enrichment was initiated by inoculation of an acetate-mineral salts medium with domestic anaerobic digestor sludge and maintained by weekly transfer for 2 years. The enrichment culture contained a Methanosarcina and several obligately anaerobic nonmethanogenic bacteria. These latter organisms formed varying degrees of association with the Methanosarcina, ranging from the nutritionally fastidious gram-negative rod called the satellite bacterium to the nutritionally nonfastidious Eubacterium limosum. The satellite bacterium had growth requirements for amino acids, a peptide, a purine base, vitamin B12, and other B vitamins. Glucose, mannitol, starch, pyruvate, cysteine, lysine, leucine, isoleucine, arginine, and asparagine stimulated growth and hydrogen production. Acetate was neither incorporated nor metabolized by the satellite organism. Since acetate was the sole organic carbon source in the enrichment culture, organism(s) which metabolize acetate (such as the Methanosarcina) must produce substrates and growth factors for associated organisms which do not metabolize acetate. PMID:677881

  10. Isolation of acetic acid bacteria from honey

    Microsoft Academic Search

    Kanlaya Kappeng; Wasu Pathom-aree

    Four thermotolerant acetic acid bacteria designated as CMU1, CMU2, CMU3 and CMU4 were isolated from six honey samples produced by three native bee species in northern Thailand, namely the dwarf honey bee (Apis florea), Asian honey bee (A. cerena) and giant honey bee (A. dorsata). All isolates were tested for their tolerance to acetic acid and ethanol at 30?C and

  11. Nomegestrol acetate/estradiol: in oral contraception.

    PubMed

    Yang, Lily P H; Plosker, Greg L

    2012-10-01

    Nomegestrol acetate/estradiol is a combined oral contraceptive with approval in many countries. This fixed-dose combination tablet contains nomegestrol acetate, a highly selective progestogen, and estradiol, a natural estrogen. It is the first monophasic combined oral contraceptive to contain estradiol, and is taken in 28-day cycles, consisting of 24 active therapy days with 4 placebo days (i.e. 24/4-day cycles). In two large, 1-year, randomized, open-label, multicentre, phase III trials in healthy adult women (aged 18-50 years), nomegestrol acetate/estradiol was at least as effective as drospirenone/ethinylestradiol as contraceptive therapy, as the pregnancy rates in women aged 18-35 years (primary efficacy population) in terms of the Pearl Index (primary endpoint) were numerically lower with nomegestrol acetate/estradiol, although the between-group difference was not statistically significant. In both trials, nomegestrol acetate/estradiol was given in a 24/4-day cycle, and drospirenone/ethinylestradiol was given in a 21/7-day cycle. The criteria for using condoms in case of forgotten doses were less stringent in the nomegestrol acetate/estradiol group than in the drospirenone/ethinylestradiol group. Nomegestrol acetate/estradiol therapy for up to 1 year was generally well tolerated in healthy adult women, with an acceptable tolerability profile in line with that expected for a combined oral contraceptive. The most commonly reported adverse events were acne and abnormal withdrawal bleeding (most often shorter, lighter or absent periods). Overall, compared with drospirenone/ethinylestradiol, nomegestrol acetate/estradiol appeared to be associated with less favourable acne-related outcomes, and shorter, lighter or absent periods. PMID:22950535

  12. Indium acetate toxicity in male reproductive system in rats.

    PubMed

    Lee, Kuo-Hsin; Chen, Hsiu-Ling; Leung, Chung-Man; Chen, Hsin-Pao; Hsu, Ping-Chi

    2014-07-01

    Indium, a rare earth metal characterized by high plasticity, corrosion resistance, and a low melting point, is widely used in the electronics industry, but has been reported to be an environmental pollutant and a health hazard. We designed a study to investigate the effects of subacute exposure of indium compounds on male reproductive function. Twelve-week old male Sprague-Dawley rats were randomly divided into test and control groups, and received weekly intraperitoneal injections of indium acetate (1.5 mg/kg body weight) and normal saline, respectively, for 8 weeks. Serum indium levels, cauda epididymal sperm count, motility, morphology, chromatin DNA structure, mitochondrial membrane potential, oxidative stress, and testis DNA content were investigated. The indium acetate-treated group showed significant reproductive toxicity, as well as an increased percentage of sperm morphology abnormality, chromatin integrity damage, and superoxide anion generation. Furthermore, positive correlations among sperm morphology abnormalities, chromatin DNA damage, and superoxide anion generation were also noted. The results of this study demonstrated the toxic effect of subacute low-dose indium exposure during the period of sexual maturation on male reproductive function in adulthood, through an increase in oxidative stress and sperm chromatin DNA damage during spermiogenesis, in a rodent model. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014. PMID:25044390

  13. Chemical cleaning of reverse osmosis and nanofiltration membranes fouled by licorice aqueous solutions

    Microsoft Academic Search

    M. R. Sohrabi; S. S. Madaeni; M. Khosravi; A. M. Ghaedi

    2011-01-01

    The aim of this work was finding optimum cleaning agents and conditions for cleaning reverse osmosis (RO) and nanofiltration (NF) membranes fouled by licorice aqueous solutions. The effect of various chemicals on flux recovery (FR) and resistance removal (RR) of the fouled membranes was investigated. For both membranes the results indicate that a combination of ethylene diamine tetra acetic acid

  14. A centrifugal method for the evaluation of polymer membranes for reverse osmosis

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.; Mccullough, R. P.

    1973-01-01

    A rapid and simple method employing the laboratory centrifuge shows promise for evaluation of membrane performance during reverse osmosis. Results are presented for cellulose acetate membranes for rejection of salt and urea dissolved solids. Implications of the study are to rapid screening of membrane performance, use in laboratories with limited facilities, and possible space waste water purification.

  15. Control of Transdermal Permeation of Hydrocortisone Acetate from Hydrophilic and Lipophilic Formulations

    Microsoft Academic Search

    Adamo Fini; Valentina Bergamante; Gian Carlo Ceschel; Celestino Ronchi; Carlos Alberto Fonseca De Moraes

    2008-01-01

    The purpose of this research was the preparation of four formulations containing hydrocortisone acetate (HCA) for topical\\u000a application, including two aqueous systems (hydrophilic microemulsion and aqueous gel) and two systems with dominant hydrophobicity\\u000a (hydrophobic microemulsion and ointment). The formulations were tested for the release and permeation of HCA across an animal\\u000a membrane. The release of HCA was found comparable for

  16. Liquid membranes

    SciTech Connect

    Araki, T. (Kyoto Inst. of Tech. (Japan)); Tsukube, H. (Okayama Univ. (Japan))

    1990-01-01

    This work describes newer applications of liquid membrane systems which contain molecular and/or ion recognizing carrier compounds and the related characteristic membrane materials. It focuses on the current knowledge about chemistry, biology and related technology of liquid membranes. It reviews the most recent advances in design and characteristics of synthetic liquid membrane transport. Up-to-date topics in the analytical and separation science, plus biomimetic membrane technology are discussed.

  17. Acetate Oxidation Is the Dominant Methanogenic Pathway from Acetate in the Absence of Methanosaetaceae†

    PubMed Central

    Karakashev, Dimitar; Batstone, Damien J.; Trably, Eric; Angelidaki, Irini

    2006-01-01

    The oxidation of acetate to hydrogen, and the subsequent conversion of hydrogen and carbon dioxide to methane, has been regarded largely as a niche mechanism occurring at high temperatures or under inhibitory conditions. In this study, 13 anaerobic reactors and sediment from a temperate anaerobic lake were surveyed for their dominant methanogenic population by using fluorescent in situ hybridization and for the degree of acetate oxidation relative to aceticlastic conversion by using radiolabeled [2-14C]acetate in batch incubations. When Methanosaetaceae were not present, acetate oxidation was the dominant methanogenic pathway. Aceticlastic conversion was observed only in the presence of Methanosaetaceae. PMID:16820524

  18. Nanofiltration of rhodium tris(triphenylphosphine) catalyst in ethyl acetate solution

    NASA Astrophysics Data System (ADS)

    Shaharun, Maizatul S.; Mustafa, Ahmad K.; Taha, Mohd F.

    2012-09-01

    Solvent resistant nanofiltration (SRNF) using polymer membranes has recently received enhanced attention due to the search for cleaner and more energy-efficient technologies. The large size of the rhodium tris(triphenylphosphine) [HRh(CO)(PPh3)3] catalyst (>400 Da) - relative to other components of the hydroformylation reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (DuraMem{trade mark, serif} 200 and DuraMem{trade mark, serif} 500) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. Good HRh(CO)(PPh3)3 rejection (>0.95) and solvent fluxes of 9.9 L/m2?h1 at 2.0 MPa were obtained in the catalyst-ethyl acetate-DuraMem 500 system. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted on the catalyst-ethyl acetate-membrane systems. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting solvent flux.

  19. Acetate Transport and Utilization in the Rat Brain

    PubMed Central

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

    2009-01-01

    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 (CMRace) 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 ( KMutil=0.01±0.14mM) was much smaller than for acetate transport through the blood-brain barrier ( KMt=4.18±0.83mM). The maximum transport capacity of acetate through the blood-brain barrier ( Vmaxt=0.96±0.18?mol/g/min) was nearly two-fold higher than the maximum rate of brain acetate utilization ( Vmaxutil=0.50±0.08?mol/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 blood-brain barrier, but occurs after entry of acetate into the brain. PMID:19393008

  20. Direct detection of the acetate-forming activity of the enzyme acetate kinase.

    PubMed

    Fowler, Matthew L; Ingram-Smith, Cheryl J; Smith, Kerry S

    2011-01-01

    Acetate kinase, a member of the acetate and sugar kinase-Hsp70-actin (ASKHA) enzyme superfamily, is responsible for the reversible phosphorylation of acetate to acetyl phosphate utilizing ATP as a substrate. Acetate kinases are ubiquitous in the Bacteria, found in one genus of Archaea, and are also present in microbes of the Eukarya. The most well characterized acetate kinase is that from the methane-producing archaeon Methanosarcina thermophila. An acetate kinase which can only utilize PP(i) but not ATP in the acetyl phosphate-forming direction has been isolated from Entamoeba histolytica, the causative agent of amoebic dysentery, and has thus far only been found in this genus. In the direction of acetyl phosphate formation, acetate kinase activity is typically measured using the hydroxamate assay, first described by Lipmann, a coupled assay in which conversion of ATP to ADP is coupled to oxidation of NADH to NAD(+) by the enzymes pyruvate kinase and lactate dehydrogenase, or an assay measuring release of inorganic phosphate after reaction of the acetyl phosphate product with hydroxylamine. Activity in the opposite, acetate-forming direction is measured by coupling ATP formation from ADP to the reduction of NADP(+) to NADPH by the enzymes hexokinase and glucose 6-phosphate dehydrogenase. Here we describe a method for the detection of acetate kinase activity in the direction of acetate formation that does not require coupling enzymes, but is instead based on direct determination of acetyl phosphate consumption. After the enzymatic reaction, remaining acetyl phosphate is converted to a ferric hydroxamate complex that can be measured spectrophotometrically, as for the hydroxamate assay. Thus, unlike the standard coupled assay for this direction that is dependent on the production of ATP from ADP, this direct assay can be used for acetate kinases that produce ATP or PP(i). PMID:22214984

  1. Determination of herbicides paraquat, glyphosate, and aminomethylphosphonic acid in marijuana samples by capillary electrophoresis.

    PubMed

    Lanaro, Rafael; Costa, José L; Cazenave, Silvia O S; Zanolli-Filho, Luiz A; Tavares, Marina F M; Chasin, Alice A M

    2015-01-01

    In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15-0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user. PMID:25413634

  2. Composition of the fractions separated by polyacrylamide gel electrophoresis of the lipopolysaccharide of a marine bacterium.

    PubMed Central

    DiRienzo, J M; MacLeod, R A

    1978-01-01

    The sugar composition of lipopolysaccharide (LPS) isolated from whole cells of Alteromonas haloplanktis 214 (previously referred to as marine pseudomonas B-16, ATCC 19855), variant 3, of the lipid A, core, and side-chain fractions derived from it, and of the LPS fractions (LPS I, II, and III) obtained by subjecting it to preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis has been determined. Conditions optimum for the release of constituent monosaccharides by hydrolysis were established. Sugars were quantitated by gas-liquid chromatography of their alditol acetate derivatives. Lipid A was detected by gel electrophoresis and by the spectral shift obtained with a carbocyanin dye. A comparison of the molar ratios of the various fractions suggest that LPS III is an LPS molecule lacking an O-antigenic side chain, whereas LPS I and II are LPS molecules differing in side-chain composition. LPS I may be a mixture of two LPS species. In double immunodiffusion experiments using anti-whole-cell serum, LPS I and II showed a homologous cross-reaction with isolated whole-cell LPS. LPS III as well as lipid A, core, and side-chain fractions failed to give rise to precipitin lines. Images PMID:101510

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

    PubMed

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

    2014-03-01

    This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L. PMID:24434701

  4. Boronate affinity saccharide electrophoresis: A novel carbohydrate analysis tool

    Microsoft Academic Search

    J. M. H. van den Elsen; T. R. Jackson; J. S. Springall; D. Rogalle; N. Masurnoto; H. C. Li; F. D'Hooge; S. P. Perera; A. T. A. Jenkins; T. D. James; J. S. Fossey

    2008-01-01

    The incorporation of specialised carbohydrate affinity ligand methacrylamido phenylboronic acid in polyacrylamide gels for fluorophore-assisted carbohydrate electrophoresis greatly improved the effective separation of saccharides that show similar mobilities in standard electrophoresis. Polyacrylamide gel electrophoresis using methacrylamido phenylboronic acid in low loading (typically 0.5-1% dry weight) was unequivocally shown to alter retention of labelled saccharides depending on their boronate affinity. While

  5. The fluid mechanics of continuous flow electrophoresis

    NASA Astrophysics Data System (ADS)

    Saville, D. A.

    1990-11-01

    The overall objective is to establish theoretically and confirm experimentally the ultimate capabilities of continuous flow electrophoresis chambers operating in an environment essentially free of particle sedimentation and buoyancy. The efforts are devoted to: (1) studying the effects of particle concentration on sample conductivity and dielectric constant. The dielectric constant and conductivity were identified as playing crucial roles in the behavior of the sample and on the resolving power and throughput of continuous flow devices; and (2) improving the extant mathematical models to predict flow fields and particle trajectories in continuous flow electrophoresis. A dielectric spectrometer was designed and built to measure the complex dielectric constant of a colloidal dispersion as a function of frequency between 500 Hz and 200 kHz. The real part of the signal can be related to the sample's conductivity and the imaginary part to its dielectric constant. Measurements of the dielectric constants of several different dispersions disclosed that the dielectric constants of dilute systems of the sort encountered in particle electrophoresis are much larger than would be expected based on the extant theory. Experiments were carried out to show that, in many cases, this behavior is due to the presence of a filamentary structure of small hairs on the particle surface. A technique for producing electrokinetically ideal synthetic latex particles by heat treating was developed. Given the ubiquitous nature of hairy surfaces with both cells and synthetic particles, it was deemed necessary to develop a theory to explain their behavior. A theory for electrophoretic mobility of hairy particles was developed. Finally, the extant computer programs for predicting the structure of electro-osmotically driven flows were extended to encompass flow channels with variable wall mobilities.

  6. SHORT COMMUNICATION Evaluation of non-ionic and zwitterionic detergents as membrane protein solubilizers

    E-print Network

    Paris-Sud XI, Université de

    1 SHORT COMMUNICATION Evaluation of non-ionic and zwitterionic detergents as membrane protein plantes, place Viala, 34060 Montpellier cedex 1, France Running title: detergents for 2D electrophoresis;2 SUMMARY The solubilizing power of various nonionic and zwitterionic detergents as membrane protein

  7. Membrane Extraction for Detoxification of Biomass Hydrolysates

    SciTech Connect

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

    2012-05-01

    Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol. Rapid removal of sulfuric acid, 5-hydroxymethyl and furfural was observed. The rate of acetic acid removal decreased as the pH of the hydrolysate increased. Regeneration of the organic extractant was achieved by back extraction into an aqueous phase containing NaOH and ethanol. A cleaning protocol consisting of flushing the hydrolysate compartment with NaOH and the organic phase compartment with pure organic phase enabled regeneration and reuse of the module. Ethanol yields from hydrolysates detoxified by membrane extraction using 15% Alamine 336 in oleyl alcohol were about 10% higher than those from hydrolysates detoxified using ammonium hydroxide treatment.

  8. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2004-06-15

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  9. Fluid mechanics of continuous flow electrophoresis

    NASA Technical Reports Server (NTRS)

    Saville, D. A.; Ostrach, S.

    1978-01-01

    The following aspects of continuous flow electrophoresis were studied: (1) flow and temperature fields; (2) hydrodynamic stability; (3) separation efficiency, and (4) characteristics of wide gap chambers (the SPAR apparatus). Simplified mathematical models were developed so as to furnish a basis for understanding the phenomena and comparison of different chambers and operating conditions. Studies of the hydrodynamic stability disclosed that a wide gap chamber may be particularly sensitive to axial temperature variations which could be due to uneven heating or cooling. The mathematical model of the separation process includes effects due to the axial velocity, electro-osmotic cross flow and electrophoretic migration, all including the effects of temperature dependent properties.

  10. Cytokine Analysis by Immunoaffinity Capillary Electrophoresis

    PubMed Central

    Mendonca, Mark; Kalish, Heather

    2014-01-01

    Immunoaffinity capillary electrophoresis (ICE) is a powerful tool used to detect and quantify target proteins of interest in complex biological fluids. The target analyte is captured and bound to antibodies immobilized onto the wall of a capillary, labeled in situ with a fluorescent dye, eluted and detected online using laser-induced fluorescence following electrophoretic separation. Here, we illustrate how to construct an immunoaffinity capillary and utilize it to run ICE in order to capture and quantify target cytokines and chemokines from a clinical sample. PMID:22976107

  11. Hybrid slab-microchannel gel electrophoresis system

    DOEpatents

    Balch, Joseph W. (Livermore, CA); Carrano, Anthony V. (Livermore, CA); Davidson, James C. (Livermore, CA); Koo, Jackson C. (San Ramon, CA)

    1998-01-01

    A hybrid slab-microchannel gel electrophoresis system. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate.

  12. Electrohydrodynamic effects in continuous flow electrophoresis

    NASA Technical Reports Server (NTRS)

    Rhodes, P. H.; Snyder, R. S.; Roberts, G. O.; Baygents, J. C.

    1991-01-01

    We demonstrate experimentally and theoretically the importance of electrohydrodynamic (EHD) flows in continuous-flow electrophoresis (CFE) separations. These flows are associated with variations in the conductivity or dielectric constant, and are quadratic in the field strength. They appear to be the main cause of extraneous and undesired flows in CFE which have degraded separation performance and have until now not been explained. We discuss the importance of EHD flows relative to other effects. We also describe possible techniques for reducing the associated degradation of CFE separations.

  13. Microfabricated capillary array electrophoresis device and method

    SciTech Connect

    Simpson, Peter C. (Oakland, CA); Mathies, Richard A. (Moraga, CA); Woolley, Adam T. (Belmont, MA)

    2000-01-01

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  14. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2485 Electrophoresis apparatus...

  15. An acetate switch regulates stress erythropoiesis.

    PubMed

    Xu, Min; Nagati, Jason S; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D; Huang, Chou-Long; Comerford, Sarah A; Hammer, Robert E; Horton, Jay D; Chen, Rui; Garcia, Joseph A

    2014-09-01

    The hormone erythropoietin (EPO), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor hypoxia-inducible factor-2 (HIF-2). We previously reported that the lysine acetyltransferase CREB-binding protein (CBP) is required for HIF-2? acetylation and efficient HIF-2-dependent EPO induction during hypoxia. We now show that these processes require acetate-dependent acetyl CoA synthetase 2 (ACSS2). In human Hep3B hepatoma cells and in EPO-generating organs of hypoxic or acutely anemic mice, acetate levels rise and ACSS2 is required for HIF-2? acetylation, CBP-HIF-2? complex formation, CBP-HIF-2? recruitment to the EPO enhancer and efficient induction of EPO gene expression. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an ACSS2-dependent manner. Moreover, in acquired and inherited chronic anemia mouse models, acetate supplementation increases EPO expression and the resting hematocrit. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and EPO induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

  16. A mammalian acetate switch regulates stress erythropoiesis

    PubMed Central

    Xu, Min; Nagati, Jason S.; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D.; Huang, Chou-Long; Comerford, Sarah A.; Hammer, Robert E.; Horton, Jay D.; Chen, Rui; Garcia, Joseph A.

    2014-01-01

    Endocrine erythropoietin (Epo), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor Hypoxia Inducible Factor 2 (HIF-2). We previously reported that the lysine acetyltransferase Cbp is required for HIF-2? acetylation and efficient HIF-2 dependent Epo induction during hypoxia. We now show these processes require acetate-dependent acetyl CoA synthetase 2 (Acss2). In Hep3B hepatoma cells and in Epo-generating organs of hypoxic or acutely anemic mice, acetate levels increase and Acss2 is required for HIF-2? acetylation, Cbp/HIF-2? complex formation and recruitment to the Epo enhancer, and efficient Epo induction. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an Acss2-dependent manner. In acquired and genetic chronic anemia mouse models, acetate supplementation also increases Epo expression and resting hematocrits. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and Epo induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

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

    NASA Technical Reports Server (NTRS)

    Richardson, D.

    1975-01-01

    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.

  18. Membrane tethering.

    PubMed

    Chia, Pei Zhi Cheryl; Gleeson, Paul A

    2014-01-01

    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

  19. Capillary electrophoresis coupled with automated fraction collection.

    PubMed

    Huge, Bonnie Jaskowski; Flaherty, Ryan J; Dada, Oluwatosin O; Dovichi, Norman J

    2014-12-01

    A fraction collector based on a drop-on-demand ink-jet printer was developed to interface capillary zone electrophoresis with a 96 well microtiter plate. We first evaluated the performance of the collector by using capillary zone electrophoresis to analyze a 1mM solution of tetramethylrhodamine; a fluorescent microtiter plate reader was then used to detect the analyte and characterize fraction carryover between wells. Relative standard deviation in peak height was 20% and the relative standard deviation in migration time was 1%. The mean and standard deviation of the tetramethylrhodamine peak width was 5 ± 1 s and likely limited by the 4-s period between droplet deposition. We next injected a complex mixture of DNA fragments and used real-time PCR to quantify the product in a CE-SELEX experiment. The reconstructed electrophoretic peak was 27 s in duration. Finally, we repeated the experiment in the presence of a 30-µM thrombin solution under CE-SELEX conditions; fractions were collected and next-generation sequencing was used to characterize the DNA binders. Over 25,000 sequences were identified with close matches to known thrombin binding aptamers. PMID:25159411

  20. Fractionation of mineral species by electrophoresis

    NASA Technical Reports Server (NTRS)

    Dunning, J. D.; Herren, B. J.; Tipps, R. W.; Snyder, R. S.

    1982-01-01

    The fractionation of fine-grained aggregates into their major components is a problem in many scientific areas including earth and planetary science. Electrophoresis, the transport of electrically charged particles, immersed in a suspension medium, by a direct current field (Bier, 1959), was employed in this study as a means of separating simulated lunar soil into its constituent minerals. In these tests, conducted in a static analytical cylindrical microelectrophoresis apparatus, samples of simulated lunar soil and samples of pure mineral constituents were placed in the chamber; the electrophoretic mobilities of the lunar soil and the individual mineral constituents were measured. In most of the suspension buffers employed separability was indicated, on the basis of differences in mobility, for all the constituent mineral species except ilmenite and pyroxene, which were not efficiently separable in any of the buffers. Although only a few suspension media were employed, the success of this initial study suggests that electrophoresis may be an important mineral fractionation option in fine-grained aggregate processing.

  1. Nonaqueous capillary electrophoresis with indirect electrochemical detection.

    PubMed

    Matysik, Frank-Michael; Marggraf, Daniela; Gläser, Petra; Broekaert, José A C

    2002-11-01

    Nonaqueous capillary electrophoresis (NACE) which makes use of organic solvents in place of conventional aqueous electrophoresis buffers is gaining increasing importance among modern separation techniques. Recently, it has been shown that amperometric detection in conjunction with acetonitrile-based NACE offers an extended accessible potential range and an enhanced long-term stability of the amperometric responses generated at solid electrodes. The present contribution takes advantage of the latter aspect to develop reliable systems for NACE with indirect electrochemical detection (IED). In this context, several compounds such as (ferrocenylmethyl)trimethylammonium perchlorate, tris(1,10-phenanthroline)cobalt(III) perchlorate and bis(1,4,7-triazacyclononane)nickel(II) perchlorate were studied regarding their suitability to act as electroactive buffer additives for IED in NACE. The performance characteristics for the respective buffer systems were evaluated. Tetraalkylammonium perchlorates served as model compounds for the optimization of the NACE-IED system. Target analytes choline and acetylcholine could easily be separated and determined by means of NACE-IED. In the case of a buffer system containing 10(-4) M tris(1,10-phenanthroline)cobalt(III) perchlorate the limits of detection were 2.5 x 10(-7) M and 4.6 x 10(-7) M for choline and acetylcholine, respectively. With the elaborated analytical procedure choline could be determined in pharmaceutical preparations. PMID:12432533

  2. Separation of nonylphenol ethoxylates and nonylphenol by non-aqueous capillary electrophoresis.

    PubMed

    Babay, Paola A; Gettar, Raquel T; Silva, María F; Thiele, Björn; Batistoni, Daniel A

    2006-05-26

    Capillary electrophoresis based on non-aqueous solvent background electrolytes was employed, with single and multiple wavelength UV detection, to evaluate discrimination among oligomer components of mixtures of non-ionic, long chain nonylphenol ethoxylates (NPnEO, with n = number of ethoxy units) and their lipophilic degradation products. The tested organic solvents included acetonitrile, methanol, ethanol, 1- and 2-propanol, 1-butanol and tetrahydrofurane in the presence of sodium acetate. A rational variation of composition of background electrolyte solvent mixtures allowed to modify the mobility of electroosmotic flow and the type and degree of interactions between the ionic additive (sodium acetate) and the components of the analyte mixtures. The physicochemical properties of the solvents, such as dielectric constant, viscosity and electron donor-acceptor ability regarding the additive, were considered to improve the resolution of lipophilic compounds with less than three ethoxy groups and the discrimination attainable for longer chain oligomers. The studied methodologies also allowed discerning between surfactants of similar (nominal) ethoxy chain lengths. This was demonstrated by the different peak distribution patterns observed for NPnEO compounds with n = 7.5 and 10, respectively. PMID:16545826

  3. [Separation of derivatized aliphatic aldehydes in beverage by nonaqueous capillary electrophoresis].

    PubMed

    Bai, Xinwei; Wang, Yanbao; Zhao, Huaixin; Sun, Zhiwei; Xia, Lian; Fu, Yanyan; Suo, Yourui; Li, Yulin; You, Jinmao

    2010-01-01

    A simple and mild method for the separation of aliphatic aldehydes based on a condensation reaction with 9,10-phenanthrenequinone as labeling reagent with nonaqueous capillary electrophoresis has been developed. The detection was performed with a diode array detector (DAD). A 58.5 cm (50 cm effective length) x 50 microm i.d. untreated fused-silica capillary was used. To optimize the conditions, the background electrolyte concentration, column temperature, voltage and other factors were evaluated. The results indicated that the buffer concentration had a great impact on the separation, but the influences of temperature and added additives on the resolution were not obvious. The optimized conditions were as follows: 80 mmol/L ammonium acetate, 1.4 mol/L acetic acid, voltage of 28 kV, column temperature of 20 degrees C and DAD detection at 254 nm. The samples were introduced atmospherically with the injection at 5 kPa (50 mbar) for 8 s. The results indicate that seven aliphatic aldehyde derivatives and actual samples can be achieved baseline resolution under the proposed conditions. PMID:20458926

  4. Antimicrobial electrospun nanofibers of cellulose acetate and polyester urethane composite for wound dressing.

    PubMed

    Liu, Xin; Lin, Tong; Gao, Yuan; Xu, Zhiguang; Huang, Chen; Yao, Gang; Jiang, Linlin; Tang, Yanwei; Wang, Xungai

    2012-08-01

    In this study, a series of nanofibrous membranes were prepared from cellulose acetate (CA) and polyester urethane (PEU) using coelectrospinning or blend-electrospinning. The drug release, in vitro antimicrobial activity and in vivo wound healing performance of the nanofiber membranes were evaluated for use as wound dressings. To prevent common clinical infections, an antimicrobial agent, polyhexamethylene biguanide (PHMB) was incorporated into the electrospun fibers. The presence of CA in the nanofiber membrane improved its hydrophilicity and permeability to air and moisture. CA fibers became slightly swollen upon contacting with liquid phase. CA not only increased the liquid uptake but also created a moist environment for the wound, which accelerated wound recovery. PHMB release dynamics of the membranes was controlled by the structure and component ratios of the membranes. The lower ratio of CA: PEU helped to preserve the physical and thermal properties of the membranes, and also reduced the burst release effectively and slowed down diffusion of PHMB during in vitro tests. The controlled-diffusion membranes exerted long-term antimicrobial effect for wound healing. PMID:22692845

  5. Unified Theory for Gel Electrophoresis and Gel Filtration

    Microsoft Academic Search

    David Rodbard; Andreas Chrambach

    1970-01-01

    Unified theory for gel electrophoresis and gel filtration: The behavior of macromolecules in gel filtration and gel electrophoresis may be predicted from Ogston's model for a random meshwork of fibers. This model has been generalized to apply to nonspherical molecules and to several gel types. The model provides equations for inter-relationships between mobility, partition coefficient, gel concentration, and molecular radius;

  6. Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials

    ERIC Educational Resources Information Center

    Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

    2012-01-01

    Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

  7. Electrophoresis 2012, 33, 10791085 1079 Kevin H. Patel

    E-print Network

    Krylov, Sergey

    for deter- mining electrolyte temperatures volve the use of built in Peltier cooling devices, forced air in a capillary electrophoresis instrument with forced-air cooling Temperature increase due to resistive electrical heating is an inherent limitation of capillary electrophoresis (CE). Active cooling systems

  8. Affinity Capillary Electrophoresis Using a Low-Concentration Additive with the Consideration

    E-print Network

    Chen, David D.Y.

    Affinity Capillary Electrophoresis Using a Low-Concentration Additive with the Consideration Chemistry, University of Pavia, Pavia, Italy 27100 Most affinity studies in capillary electrophoresis assume capillary electrophoresis (CE) have been used to measure binding parameters because of their ability

  9. Tandem Isotachophoresis-Zone Electrophoresis via Base-Mediated Destacking for Increased

    E-print Network

    Barron, Annelise E.

    Tandem Isotachophoresis-Zone Electrophoresis via Base-Mediated Destacking for Increased Detection Engineering, Northwestern University, Evanston, Illinois 60208 Electrophoresis in microfluidic devices electrophoresis devices. This capability is provided by the implementation of a particular buffer system

  10. Temperature Gradient Capillary Electrophoresis (TGCE) Related Protocols 1 TEMPERATURE GRADIENT CAPILLARY

    E-print Network

    Wurtele, Eve Syrkin

    Temperature Gradient Capillary Electrophoresis (TGCE) Related Protocols 1 TEMPERATURE GRADIENT CAPILLARY ELECTROPHORESIS (TGCE) RELATED PROTOCOLS (Last Revised: April, 2007) These protocols were Gradient Capillary Electrophoresis (TGCE) Related Protocols 2 PCR program used to denature/re-anneal mixed

  11. Treatment of Pedophilia with Leuprolide Acetate

    Microsoft Academic Search

    Nancy Raymond; Bean Robinson; Chris Kraft; Barry Rittberg; Eli Coleman

    2002-01-01

    To date, the literature on the treatment of individuals who have committed sexual offenses has focused primarily on psychotherapeutic interventions and the use of antiandrogens. Recently case reports and small series supporting the efficacy of other psychiatric medication, such as serotonin reuptake inhibitors, have been published. Only a few publications have looked at the efficacy of leuprolide acetate, an LH-RH

  12. Heat Bonding of Irradiated Ethylene Vinyl Acetate

    NASA Technical Reports Server (NTRS)

    Slack, D. H.

    1986-01-01

    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.

  13. Process for the preparation of vinyl acetate

    DOEpatents

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

    1998-01-01

    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.

  14. Electrophoresis in nanochannels: brief review and speculation

    PubMed Central

    Baldessari, Fabio; Santiago, Juan G

    2006-01-01

    The relevant physical phenomena that dominate electrophoretic transport of ions and macromolecules within long, thin nanochannels are reviewed, and a few papers relevant to the discussion are cited. Sample ion transport through nanochannels is largely a function of their interaction with electric double layer. For small ions, this coupling includes the net effect of the external applied field, the internal field of the double layer, and the non-uniform velocity of the liquid. Adsorption/desorption kinetics and the effects of surface roughness may also be important in nanochannel electrophoresis. For macromolecules, the resulting motion is more complex as there is further coupling via steric interactions and perhaps polarization effects. These complex interactions and coupled physics represent a valuable opportunity for novel electrophoretic and chromatographic separations. PMID:17116262

  15. Hybrid slab-microchannel gel electrophoresis system

    DOEpatents

    Balch, J.W.; Carrano, A.V.; Davidson, J.C.; Koo, J.C.

    1998-05-05

    A hybrid slab-microchannel gel electrophoresis system is described. The hybrid system permits the fabrication of isolated microchannels for biomolecule separations without imposing the constraint of a totally sealed system. The hybrid system is reusable and ultimately much simpler and less costly to manufacture than a closed channel plate system. The hybrid system incorporates a microslab portion of the separation medium above the microchannels, thus at least substantially reducing the possibility of non-uniform field distribution and breakdown due to uncontrollable leakage. A microslab of the sieving matrix is built into the system by using plastic spacer materials and is used to uniformly couple the top plate with the bottom microchannel plate. 4 figs.

  16. Strongly nonlinear waves in capillary electrophoresis

    E-print Network

    Chen, Zhen

    2012-01-01

    In capillary electrophoresis, sample ions migrate along a micro-capillary filled with a background electrolyte under the influence of an applied electric field. If the sample concentration is sufficiently high, the electrical conductivity in the sample zone could differ significantly from the background.Under such conditions, the local migration velocity of sample ions becomes concentration dependent resulting in a nonlinear wave that exhibits shock like features. If the nonlinearity is weak, the sample concentration profile, under certain simplifying assumptions, can be shown to obey Burgers' equation (S. Ghosal and Z. Chen Bull. Math. Biol. 2010, 72(8), pg. 2047) which has an exact analytical solution for arbitrary initial condition.In this paper, we use a numerical method to study the problem in the more general case where the sample concentration is not small in comparison to the concentration of background ions. In the case of low concentrations, the numerical results agree with the weakly nonlinear theo...

  17. Flow structure in continuous flow electrophoresis chambers

    NASA Technical Reports Server (NTRS)

    Deiber, J. A.; Saville, D. A.

    1982-01-01

    There are at least two ways that hydrodynamic processes can limit continiuous flow electrophoresis. One arises from the sensitivity of the flow to small temerature gradients, especially at low flow rates and power levels. This sensitivity can be suppressed, at least in principle, by providing a carefully tailored, stabilizing temperature gradient in the cooling system that surrounds the flow channel. At higher power levels another limitation arises due to a restructuring of the main flow. This restructuring is caused by buoyancy, which is in turn affected by the electro-osmotic crossflow. Approximate solutions to appropriate partial differential equations have been computed by finite difference methods. One set of results is described here to illustrate the strong coupling between the structure of the main (axial) flow and the electro-osmotic flow.

  18. Combined electrophoresis-electrospray interface and method

    DOEpatents

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

    1989-01-01

    A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

  19. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Y.

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {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.

  20. Multiple forms with glucose 6-phosphate dehydrogenase activity in Musca domestica L. as revealed by electrophoresis on cellulose acetate gel.

    PubMed

    Cima, L; Malacrida, A; Gasperi, G; Sacchi, L; Grigolo, A

    1978-10-01

    Single newly emerged males of Musca domestica, WHO strain, usually show five electrophoretic bands of glucose 6-phosphate dehydrogenase (G6PD) activity. Of these five molecular forms, designated with Roman numerals in order from the origin, we have considered the first three: these have been characterized with respect to their substrate and coenzyme specificity and to their sensitivity to some sulfhydryl inhibitors. The data show band III to be G6P specific, nicotinamide adenine dinucleotide phosphate dependent and to be a type I enzyme according to Kamada and Hori's classification. Bands I and II, on the other hand, show wide substrate specificity and low sensitivity to the sulfhydryl inhibitors assayed. In addition, in the absence of an exogenous substrate and in the presence of nicotinamide adenine dinucleotide as a coenzyme, fairly weak bands, which can be ascribed to the so called "nothing dehydrogenase" effect, are seen in the position I and II. Nevertheless, the data reported do not allow a clear definition of the enzymatic type corresponding to bands I and II of G6PD activity. PMID:31398

  1. Determination of trace metals by capillary electrophoresis.

    PubMed

    Fung, Y F; Lau, K M

    2001-07-01

    A new analytical procedure is developed using a strong complexing agent, 1,10-phenanthroline (Phen), for direct UV detection of Zn, Mn, Cu, Co, Cd, and Fe at microg/L concentrations in environmental water samples. The metal chelates formed showed different electrophoretic mobilities and solved the comigration problem for capillary electrophoresis (CE) separation of free metal ions. To obtain stable metal-Phen chelates during the capillary zone electrophoresis (CZE) run, both pre-column and on-column complexation are required and threefold excess of Phen over metal ions should be added to the sample. The optimized background electrolyte (BGE) consists of 30 mM hydroxylamine hydrochloride and 0.1% methanol at pH 3.6. Under hydrodynamic sampling, CE run at + 20 kV in 65 cm x 0.05 mm ID fused-silica column with detection at 265 nm, baseline separation, satisfactory working ranges (10 microg/L to 5.5 mg/L), sensitive detection limits (1-3 microg/L), good repeatability for migration times (relative standard deviation, RSD 0.36-0.81%, n = 5), peak area (RSD 3.2-4.2%, n = 5) and peak height (RSD 3.2-4.5%, n = 5) were obtained for the metal cations investigated. The reliability of the method was established by parallel determination using the inductively coupled plasma-atomic emission spectrometry (ICP-AES) method giving results within statistical variation. The procedure developed is shown to provide a quick, sensitive, precise, and economic method for simultaneous determination of metal cations that can form stable chelates with Phen. PMID:11504052

  2. High-performance capillary electrophoresis of gangliosides.

    PubMed

    Liu, Y B; Chan, K F

    1991-06-01

    Gangliosides are sialic acid-containing glycosphingolipids. In aqueous media, these glycolipids have been shown to exist as stable micelles. Ganglioside micelles could be analyzed by high-performance zonal capillary electrophoresis in uncoated fused-silica capillaries within 10 min. The mass sensitivity determined by monitoring the absorption of ultraviolet light at 195 nm was in the order of 10(-11) mol. Increasing the pH of the running buffer from 3.0 to 7.4 or the voltage from 10 to 30 kV increased the relative mobilities of gangliosides. By contrast, increasing the ionic strength of the buffer decreased the migration and broadened the elution peak widths of gangliosides. Ganglioside* micelles including GM1, GD1b, and GT1b were resolved into separate peaks by capillary electrophoresis at physiological pH shortly after mixing. Upon prolonged incubation, the ganglioside peaks merged to form a single species. The fusion process was temperature-dependent. At 50 degrees C, formation of mixed micelles between polysialogangliosides GD1b and GT1b was complete within 30 min. In contrast, no fusion of the ganglioside peaks was observed at 0 degrees C even after 75 h. Formation of mixed micelles between GD1b and other polysialogangliosides including GD1a, GT1b, and GQ1b at 37 degrees C required 1.5, 3.0, and 2.0 h, respectively. Formation of mixed micelles between monosialoganglioside GM1 and polysialogangliosides were 6- to 36-fold slower. No fusion was observed between monosialogangliosides GM1 and GM2 after 2 days of incubation. These findings indicate that polysialogangliosides may have higher propensities than monosialoganglioside to form mixed micelles. PMID:1889389

  3. Cathepsin D protects colorectal cancer cells from acetate-induced apoptosis through autophagy-independent degradation of damaged mitochondria.

    PubMed

    Oliveira, C S F; Pereira, H; Alves, S; Castro, L; Baltazar, F; Chaves, S R; Preto, A; Côrte-Real, M

    2015-01-01

    Acetate is a short-chain fatty acid secreted by Propionibacteria from the human intestine, known to induce mitochondrial apoptotic death in colorectal cancer (CRC) cells. We previously established that acetate also induces lysosome membrane permeabilization in CRC cells, associated with release of the lysosomal protease cathepsin D (CatD), which has a well-established role in the mitochondrial apoptotic cascade. Unexpectedly, we showed that CatD has an antiapoptotic role in this process, as pepstatin A (a CatD inhibitor) increased acetate-induced apoptosis. These results mimicked our previous data in the yeast system showing that acetic acid activates a mitochondria-dependent apoptosis process associated with vacuolar membrane permeabilization and release of the vacuolar protease Pep4p, ortholog of mammalian CatD. Indeed, this protease was required for cell survival in a manner dependent on its catalytic activity and for efficient mitochondrial degradation independently of autophagy. In this study, we therefore assessed the role of CatD in acetate-induced mitochondrial alterations. We found that, similar to acetic acid in yeast, acetate-induced apoptosis is not associated with autophagy induction in CRC cells. Moreover, inhibition of CatD with small interfering RNA or pepstatin A enhanced apoptosis associated with higher mitochondrial dysfunction and increased mitochondrial mass. This effect seems to be specific, as inhibition of CatB and CatL with E-64d had no effect, nor were these proteases significantly released to the cytosol during acetate-induced apoptosis. Using yeast cells, we further show that the role of Pep4p in mitochondrial degradation depends on its protease activity and is complemented by CatD, indicating that this mechanism is conserved. In summary, the clues provided by the yeast model unveiled a novel CatD function in the degradation of damaged mitochondria when autophagy is impaired, which protects CRC cells from acetate-induced apoptosis. CatD inhibitors could therefore enhance acetate-mediated cancer cell death, presenting a novel strategy for prevention or therapy of CRC. PMID:26086961

  4. Phenyl Acetate Preparation from Phenol and Acetic Acid: Reassessment of a Common Textbook Misconception.

    ERIC Educational Resources Information Center

    Hocking, M. B.

    1980-01-01

    Reassesses a common textbook misconception that "...phenols cannot be esterified directly." Results of experiments are discussed and data tables provided of an effective method for the direct preparation of phenyl acetate. (CS)

  5. Evaluation of different protein extraction methods for banana (Musa spp.) root proteome analysis by two-dimensional electrophoresis.

    PubMed

    Vaganan, M Mayil; Sarumathi, S; Nandakumar, A; Ravi, I; Mustaffa, M M

    2015-02-01

    Four protocols viz., the trichloroacetic acid-acetone (TCA), phenol-ammonium acetate (PAA), phenol/SDS-ammonium acetate (PSA) and trisbase-acetone (TBA) were evaluated with modifications for protein extraction from banana (Grand Naine) roots, considered as recalcitrant tissues for proteomic analysis. The two-dimensional electrophoresis (2-DE) separated proteins were compared based on protein yield, number of resolved proteins, sum of spot quantity, average spot intensity and proteins resolved in 4-7 pI range. The PAA protocol yielded more proteins (0.89 mg/g of tissues) and protein spots (584) in 2-DE gel than TCA and other protocols. Also, the PAA protocol was superior in terms of sum of total spot quantity and average spot intensity than TCA and other protocols, suggesting phenol as extractant and ammonium acetate as precipitant of proteins were the most suitable for banana rooteomics analysis by 2-DE. In addition, 1:3 ratios of root tissue to extraction buffer and overnight protein precipitation were most efficient to obtain maximum protein yield. PMID:26040117

  6. Simultaneous Capillary Gas Chromatographic Determination of Cyproterone Acetate and 15?-Hydroxycyproterone Acetate in Urine

    Microsoft Academic Search

    Jasmina Novakovic; Eva Tvrzická

    1993-01-01

    The simultaneous capillary GC determination of underivatized antiandrogen cyproterone acetate (CPA) and its active metabolite 15?-hydroxycyproterone acetate (OH-CPA) in spiked urine was performed on a flexible VCOT quartz capillary column, coated with a non-polar CP-Sil 5 CB liquid phase. A split\\/splitless injector and a flame-ionization detector were used. Equilin was used as an internal standard, and resolution of all the

  7. The effect of acetic acid and acetate on CO2 corrosion of carbon steel

    Microsoft Academic Search

    Dong Liu; ZhenYu Chen; XingPeng Guo

    2008-01-01

    Purpose – The purpose of this paper is to consider the effect of acetic acid and acetate on the anodic and cathodic reactions of carbon steel present in CO2 corrosion. Design\\/methodology\\/approach – The corrosion behaviour of carbon steel (N80) in CO2-saturated 1% NaCl solution at 50°C and 0.1 MPa was investigated by using weight-loss tests, electrochemical methods (polarization curves and

  8. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  9. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  10. Studies on an acetate-fermenting strain of Methanosarcina.

    PubMed

    Mah, R A; Smith, M R; Baresi, L

    1978-06-01

    An acetate-fermenting strain of Methanosarcina was isolated from an acetate enrichment culture inoculated with anaerobic sludge from a waste treatment digestor. In pure culture, this organism fermented acetate in the absence of added hydrogen at rates comparable in magnitude to those found in digestor systems. This rate was significantly higher than previously obtained for pure cultures of this genus. Mineral components of yeast extract were highly stimulatory for cultures growing on methanol. Comparable stimulation was not observed for cultures growing on acetate. Labeling studies indicated that acetate was converted to methane and CO2 as predicted by previous studies on mixed cultures. Total oxidation or reduction of acetate was not the mechanism of conversion of acetate to methane by the pure culture. The ability of this strain to form colonies or to produce methane from acetate was apparently influenced by the choice of substrate and conditions used for growing the inoculum. PMID:677880

  11. Expression of Acetate Permease-like (apl) Genes in Subsurface Communities of Geobacter Species Under Fluctuating Acetate Concentrations

    SciTech Connect

    Elifantz, H.; N'Guessan, A. L.; Mouser, Paula; Williams, Kenneth H.; Wilkins, Michael J.; Risso, Carla; Holmes, Dawn; Long, Philip E.; Lovley, Derek R.

    2010-09-01

    The addition of acetate to uranium-contaminated aquifers in order to stimulate the growth and activity of Geobacter species that reduce uranium is a promising in situ bioremediation option. Optimizing this bioremediation strategy requires that suf?cient acetate be added to promote Geobacter species growth. We hypothesized that under acetate-limiting conditions, subsurface Geobacter species would increase the expression of either putative acetate symporters genes (aplI and aplII). Acetate was added to a uranium-contaminated aquifer (Ri?e, CO) in two continuous amendments separated by 5 days of groundwater ?ush to create changing acetate concentrations. While the expression of aplI in monitoring well D04 (high acetate) weakly correlated with the acetate concentration over time, the transcript levels for this gene were relatively constant in well D08 (low acetate). At the lowest acetate concentrations during the groundwater ?ush, the transcript levels of aplII were the highest. The expression of aplII decreased 2–10-fold upon acetate reintroduction. However, the overall instability of acetate concentrations throughout the experiment could not support a robust conclusion regarding the role of apl genes in response to acetate limitation under ?eld conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

  12. Ferroelectric thin film bismuth titanate prepared from acetate precursor

    Microsoft Academic Search

    Yanxia Lu; David T. Hoelzer; Walter A. Schulze; Bmce Tuttle; B. G. Potter

    1994-01-01

    Bismuth titanate (Bi4Ti3O12) thin films were fabricated by spin coat deposition-rapid thermal processing (RTP) technique. Acetate derived solution for deposition was synthesized by blending dissolved bismuth acetate in aqueous acetic acid, and then adding with titanium acetate. A series of electrically insulating, semiconducting and conducting substrates were evaluated for Bi4 Ti3O12 films deposition. While X-ray diffraction and TEM analyses indicated

  13. Electrophoresis 2012, 33, 28672874 2867 Jaka Cemazar

    E-print Network

    Ljubljana, University of

    deactivation, particularly in food preservation [8]. For optimal efficiency of a particular application of elec. Reversible electroporation is already an estab- lished method for introduction of membrane is a method for tissue Correspondence: Dr. Tadej Kotnik, Faculty of Electrical Engineer- ing, University

  14. Development of an Amperometric Acetic Acid Sensor in Organic System

    Microsoft Academic Search

    Shin Lin; Tse-Chuan Chou

    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

  15. Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins

    ERIC Educational Resources Information Center

    Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

    2011-01-01

    A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

  16. Original article Ethanol and acetic-acid tolerance

    E-print Network

    Paris-Sud XI, Université de

    Original article Ethanol and acetic-acid tolerance in Indian geographical populations of Drosophila clines of ethanol toler- ance (1.5-4.2%) and acetic-acid tolerance (2.9-4.9%) were observed in adult individuals of 4 geographical populations of Drosophila immigrans. Thus, both ethanol and acetic

  17. Facile hydrolysis and alcoholysis of palladium acetate.

    PubMed

    Bedford, Robin B; Bowen, John G; Davidson, Russell B; Haddow, Mairi F; Seymour-Julen, Annabelle E; Sparkes, Hazel A; Webster, Ruth L

    2015-05-26

    Palladium(II) acetate is readily converted into [Pd3 (?(2) -OH)(OAc)5 ] (1) in the presence of water in a range of organic solvents and is also slowly converted in the solid state. Complex 1 can also be formed in nominally anhydrous solvents. Similarly, the analogous alkoxide complexes [Pd3 (?(2) -OR)(OAc)5 ] (3) are easily formed in solutions of palladium(II) acetate containing a range of alcohols. An examination of a representative Wacker-type oxidation shows that the Pd-OH complex 1 and a related Pd-oxo complex 4 can be excluded as potential catalytic intermediates in the absence of exogenous water. PMID:25865439

  18. Assessment Guidelines for Managing Cellulose Acetate Collections

    NSDL National Science Digital Library

    2001-01-01

    Photographic negatives, motion picture film, microfilm, and sound recordings produced from the 1930s into the 1950s often used cellulose acetate as the transparent plastic carrier. As anyone who has ever come in contact with it well knows, its strong vinegar-like scent is hard to miss. Unfortunately, over time, the material is prone to deterioration, which eventually renders it unusable. In an effort to help guide libraries in Australia with this problem, the National Library of Australia has created this document. It provides assistance in identification of cellulose acetate (vs. other similar materials) and establishes criteria to assess condition, cultural importance, and use within the library or storage context. The document guides readers through the first step in a strategy for preserving these collections.

  19. Ulipristal acetate: the newest emergency contraceptive.

    PubMed

    Wilton, Jeanne M

    2012-01-01

    More than 50 percent of pregnancies in the United States are unplanned. Emergency contraception has been shown to possibly reduce the risk of pregnancy by as much as 75 percent. Ulipristal acetate is a selective progesterone receptor modulator that was approved by the U.S. Food and Drug Administration (FDA) for emergency contraceptive use in August 2010. This article reviews information on its mechanism of action, efficacy, safety and implications for women's health nurses. PMID:22900810

  20. Mechanical and optical characterization of cellulose acetate

    Microsoft Academic Search

    H. Ishikawa; S. Tadano

    1988-01-01

    To obtain the basic relations for photo-viscoelastoplastic stress analysis using cellulose acetate, the effect of strain rate\\u000a as well as room temperature on mechanical and optical properties was precisely investigated by the uniaxial tension test.\\u000a As a result, the nonlinear stress-strain, the non-linear-stress-fringe order and the nonlinear-fringe-order strain relations\\u000a were uniquely reoresented in their nondimensional forms regardless of strain rate

  1. Calcium magnesium acetate production and cost reduction

    SciTech Connect

    Leuschner, A.P.

    1988-02-01

    The New York State Energy Research and Development Authority (Energy Authority), Consolidated Edison Company of New York, Inc. (ConEd), the New York State Department of Transportation (NYSDOT), the New York State Thruway Authority (NYSTA), Chevron Chemical Company, the National Corn Growers Association (NCGA), and the Massachusetts Department of Public Works (MDPW) sponsored a research program to develop technology capable of producing Calcium Magnesium Acetate (CMA), an alternative road deicer, at a quality and cost which will allow its increased use. The objectives of this program were to determine the feasibility of: (1) producing CMA from regionally available waste and low grade organic feedstocks via biochemical engineering technologies; (2) operating the fermentation at concentrated product levels to reduce energy requirements and minimize drying process costs; (3) using this production approach to produce an environmentally acceptable CMA product; and (4) using and adapting an existing facility for a CMA commercial demonstration plant. The experimental program included:(1) selection of microorganisms for their ability to grow in the absence of sodium chloride and to tolerate high concentrations of calcium, magnesium, and acetate ions; (2) analysis of waste feedstocks for their potential conversion to acetate; (3) analysis of waste organic material for impurities in CMA that could carry over into the environment; (4) batch experiments to determine pH tolerance, growth in the absence of sodium chloride (NaCl), tolerance to magnesium, calcium and acetate ions, effect of substrate concentration, acid distribution, and acid production; and (5) semi-continuous laboratory scale anaerobic digestion experiments to determine loading rates, conversion efficiencies, and other design data. 67 refs., 33 figs., 66 tabs.

  2. Nonlinear Dielectric Relaxation Spectra of Polyvinyl Acetate

    Microsoft Academic Search

    Takeo Furukawa; Kiyokazu Matsumoto

    1992-01-01

    The frequency spectra of the linear and third nonlinear permittivities, \\\\varepsilon1* and \\\\varepsilon3*, have been measured for polyvinyl acetate (PVAc) at temperatures above Tg. The Debye relaxation of \\\\varepsilon1* associated with the micro-Brownian motion of noncrystalline segments is found to be accompanied by the complex frequency dependence of \\\\varepsilon3* due to combined contributions from the intrinsic nonlinear dielectricity and the

  3. Evaluation of proliferation and functional differentiation of LLC-PK1 cells on porous polymer membranes for the development of a bioartificial renal tubule device.

    PubMed

    Sato, Yoshinobu; Terashima, Masuo; Kagiwada, Naoko; Tun, Tun; Inagaki, Miho; Kakuta, Takatoshi; Saito, Akira

    2005-01-01

    To develop a bioartificial renal tubule system using renal tubular cells and porous polymer membrane hollow fibers, long-term maintenance of a confluent monolayer and the functionally differentiated condition of cells is essential. We examined the proliferation and functional differentiation of LLC-PK1 (Lewis-lung cancer porcine kidney 1) cells on two types of membranes: polysulfone and cellulose acetate. Cell proliferation was significantly higher on the polysulfone membrane than on the cellulose acetate membrane, and was enhanced by coating the membranes with various extracellular matrices. Confluent monolayer formation of cells was observed on matrix-coated polysulfone membrane but not on matrix-coated cellulose acetate membrane within 1 week. Cell proliferation continued for 3 weeks after confluent monolayer formation. Messenger RNA (mRNA) expression of glucose transporters, indicators of the functional differentiation of the LLC-PK1 cells, was observed in the polysulfone and cellulose acetate membrane groups, but was not observed in the nonporous polystyrene plate group under subconfluent conditions. Expression of glucose transporters mRNA was maintained for 3 weeks after confluent monolayer formation. Polysulfone membrane is more suitable than cellulose acetate membrane for a bioartificial renal tubule system with regard to LLC-PK1 cell proliferation. Extracellular matrix coating of the membrane further improves cell proliferation. PMID:16259605

  4. Amphiphilic Membranes

    E-print Network

    Luca Peliti

    2005-07-26

    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

  5. Experimental evidence of an acetate transporter protein and characterization of acetate activation in aceticlastic methanogenesis of Methanosarcina mazei.

    PubMed

    Welte, Cornelia; Kröninger, Lena; Deppenmeier, Uwe

    2014-10-01

    Aceticlastic methanogens metabolize acetate to methane and carbon dioxide. The central metabolism and the electron transport chains of these organisms have already been investigated. However, no particular attention has been paid to the mechanism by which acetate enters the archaeal cell. In our study we investigated Methanosarcina mazei acetate kinase (Ack) and the acetate uptake reaction. At a concentration of 2 mM acetate, the Ack activity in cell extract of M. mazei was not limiting for the methane formation rate. Instead, the methanogenesis rate was controlled by the substrate concentration and increased 10-fold at 10 mM acetate. Subsequently, we analyzed the involvement of the putative acetate permease MM_0903 using a corresponding deletion mutant. At 2 mM acetate, only 25% of the wild-type methane formation rate was measured in the mutant. This indicated that the supply of acetate to Ack was limiting the rate of methane formation. Moreover, the mutant revealed an increased acetate kinase activity compared with the wild type. These results show for the first time that an acetate transporter is involved in aceticlastic methanogenesis and may be an important factor in the acetate threshold concentration for methanogenesis of Methanosarcina spp. PMID:25088360

  6. DNA sequencing using fluorescence background electroblotting membrane

    DOEpatents

    Caldwell, Karin D. (Salt Lake City, UT); Chu, Tun-Jen (Salt Lake City, UT); Pitt, William G. (Orem, UT)

    1992-01-01

    A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through said smino groups contained on the surface thereof. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to said target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membrances may be reprobed numerous times.

  7. Capillary electrophoresis for total glycosaminoglycan analysis.

    PubMed

    Ucakturk, Ebru; Cai, Chao; Li, Lingyun; Li, Guoyun; Zhang, Fuming; Linhardt, Robert J

    2014-07-01

    A capillary zone electrophoresis-laser-induced fluorescence detection (CZE-LIF) method was developed for the simultaneous analysis of disaccharides derived from heparan sulfate, chondroitin sulfate/dermatan sulfate, hyaluronan, and keratan sulfate. Glycosaminoglycans (GAGs) were first depolymerized with the mixture of GAG lyases (heparinase I, II, III and chondroitinase ABC and chondroitinase AC II) and GAG endohydrolase (keratinase II) and the resulting disaccharides were derivatized by reductive amination with 2-aminoacridone. Nineteen fluorescently labeled disaccharides were separated using 50 mM phosphate buffer (pH 3.3) under reversed polarity at 25 kV. Using these conditions, all the disaccharides examined were baseline separated in less then 25 min. This CZE-LIF method gave good reproducibility for both migration time (?1.03% for intraday and ?4.4% for interday) and the peak area values (?5.6% for intra- and ?8.69% for interday). This CZE-LIF method was used for profiling and quantification of GAG derivative disaccharides in bovine cornea. The results show that the current CZE-LIF method offers fast, simple, sensitive, reproducible determination of disaccharides derived from total GAGs in a single run. PMID:24817364

  8. Denaturing Urea Polyacrylamide Gel Electrophoresis (Urea PAGE)

    PubMed Central

    Summer, Heike; Grämer, René; Dröge, Peter

    2009-01-01

    Urea PAGE or denaturing urea polyacrylamide gel electrophoresis employs 6-8 M urea, which denatures secondary DNA or RNA structures and is used for their separation in a polyacrylamide gel matrix based on the molecular weight. Fragments between 2 to 500 bases, with length differences as small as a single nucleotide, can be separated using this method1. The migration of the sample is dependent on the chosen acrylamide concentration. A higher percentage of polyacrylamide resolves lower molecular weight fragments. The combination of urea and temperatures of 45-55 °C during the gel run allows for the separation of unstructured DNA or RNA molecules. In general this method is required to analyze or purify single stranded DNA or RNA fragments, such as synthesized or labeled oligonucleotides or products from enzymatic cleavage reactions. In this video article we show how to prepare and run the denaturing urea polyacrylamide gels. Technical tips are included, in addition to the original protocol 1,2. PMID:19865070

  9. Mini-electrochemical detector for microchip electrophoresis.

    PubMed

    Jiang, Lei; Lu, Yao; Dai, Zhongpeng; Xie, Minhao; Lin, Bingcheng

    2005-09-01

    This paper presents the development of a mini-electrochemical detector for microchip electrophoresis. The small size (3.6 x 5.0 cm2, W x L) of the detector is compatible with the dimension of the microchip. The use of universal serial bus (USB) ports facilitates installation and use of the detector, miniaturizes the detector, and makes it ideal for lab-on-a-chip applications. A fixed 10 M ohm feedback resistance was chosen to convert current of the working electrode to voltage with second gain of 1, 2, 4, 8, 16, 32, 64 and 128 for small signal detection instead of adopting selectable feedback resistance. Special attention has been paid to the power support circuitry and printed circuit board (PCB) design in order to obtain good performance in such a miniature size. The working electrode potential could be varied over a range of +/-2.5 V with a resolution of 0.01 mV. The detection current ranges from -0.3 x 10(-7) A to 2.5 x 10(-7) A and the noise is lower than 1 pA. The analytical performance of the new system was demonstrated by the detection of epinephrine using an integrated PDMS/glass microchip with detection limit of 2.1 microM (S/N = 3). PMID:16100576

  10. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  11. Characterization of carboxylated nanolatexes by capillary electrophoresis.

    PubMed

    Oukacine, Farid; Morel, Aurélie; Cottet, Hervé

    2011-04-01

    Poly(styrene-co-acrylic acid) (St/AA) and poly(styrene-co-methacrylic acid) (St/MA) nanolatexes with different acid contents were prepared by emulsion copolymerization and were analyzed by capillary electrophoresis (CE) and by laser doppler velocimetry (LDV). Due to the intrinsic differences in the methodologies, CE (separative technique) and LDV (zetametry, nonseparative technique) lead to very different electrophoretic mobility distributions. Beyond these differences, the variation of the electrophoretic mobility is a complex and nonlinear function of the hydrodynamic radius, the ionic strength, and the zeta potential. To gain better insight on the influence of the ionic strength and the acid content on the electrophoretic behavior of the nanolatexes, the electrophoretic mobility data were changed into surface charge densities using the O'Brien, White, and Ohshima modeling. This approach leads to the conclusion that the surface charge density is mainly controlled at high ionic strength (?50 mM) by the adsorption of anionic surfactants coming from the sample. On the contrary, at low ionic strength, and/or in the presence of neutral surfactant in the electrolyte, the acid content was the main parameter controlling the surface charge density of the nanolatexes. PMID:21344892

  12. 21 CFR 862.2485 - Electrophoresis apparatus for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...electrophoresis apparatus for clinical use is a device intended to separate molecules or particles, including plasma proteins, lipoproteins, enzymes, and hemoglobulins on the basis of their net charge in specified buffered media. This device is used in...

  13. Single molecule analysis of DNA electrophoresis in microdevices

    E-print Network

    Randall, Greg C

    2006-01-01

    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 ...

  14. ELECTROPHORESIS GEL BUFFER RECIRCULATOR FOR UNDER 20 DOLLARS

    EPA Science Inventory

    Procedures requiring extended periods of electrophoresis frequently require recirculation of the get buffer in order to reduce gel artifacts. ere we describe a recirculation device which can be built inexpensively and will fit many different model get boxes....

  15. CAPILLARY ELECTROPHORESIS FOR THE CHARACTERIZATION OF HUMIC SUBSTANCES

    EPA Science Inventory

    The potential of high performance capillary electrophoresis (HPCE), especially in the free solution mode (FSCE), is demonstrated for the analysis/characterization of environmental humic substances (HUS). he very high efficiency of HPCE separations allows the production of electro...

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

    NASA Technical Reports Server (NTRS)

    Todd, P. W.; Hjerten, S.

    1985-01-01

    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.

  17. Preparation of supported palladium membrane and separation of hydrogen

    Microsoft Academic Search

    Kanna Aoki; Shuichi Yokoyama; Katsuki Kusakabe; Shigeharu Morooka

    1996-01-01

    Palladium acetate was sublimed at a reduced pressure at 400°C., carried into the macropores of the porous wall of an ?-alumina\\u000a support tube and was decomposed there. A thin palladium membrane which was thus formed showed a hydrogen permeance of 106 mol·m2·s1.-Pa1 and a hydrogen\\/nitrogen permselectivity higher than 1000. The membrane was stable against hydrogen embrittlement even when\\u000a the permeation

  18. Determination of acid dissociation constants by capillary electrophoresis

    Microsoft Academic Search

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

    2004-01-01

    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

  19. Rapid Covalent Method for Fabrication of Optical pH Sensitive Membranes

    Microsoft Academic Search

    Yordan Kostov; Alexander Neykov

    2000-01-01

    A new method for covalent immobilization of pH indicators was developed.Indicators, containing amino groups, are immobilized covalently on transparent hydrolyzed acet[ydot]lcellulose membranes. All the steps were performed at ambient temperature. The method was rapid and allows for preparation of the final membranes within one day.

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

    Microsoft Academic Search

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

    1994-01-01

    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

  1. Fouling of reverse osmosis membranes by hydrocarbonated and fluorinated surfactants contained in firefighting water

    E-print Network

    Paris-Sud XI, Université de

    Title: Fouling of reverse osmosis membranes by hydrocarbonated and fluorinated surfactants osmosis efficiently treated the water from fire extinguishment. In this work we focused on the reverse osmosis step. Polyamide and cellulose acetate membrane materials were screened in a flat sheet cell

  2. Development of reverse osmosis desalination membranes composition and configuration: Future prospects

    Microsoft Academic Search

    M. Gamal Khedr

    2003-01-01

    The most common reverse osmosis (RO) membranes which attained the stage of economic application in desalination plants are made of cellulose acetate (CA) or polyamide (PA), in either hollow fiber (HF) or spiral wound (SW) configurations. The first application problem of CA membrane is its sensitivity to hydrolysis being both a polysaccharide and polyester. The resulting deacetylation of the surface

  3. Hollow-fibre membrane module design: comparison of different curved geometries with Dean vortices

    Microsoft Academic Search

    J. N Ghogomu; C Guigui; J. C Rouch; M. J Clifton; P Aptel

    2001-01-01

    The performance of several designs of curved membrane modules with Dean vortices was compared through experiments using a colloidal bentonite suspension and cellulose acetate hollow-fibre ultrafiltration (UF) membranes. The different module geometries were: straight, helically coiled, twisted and sinusoidal, or meander-shaped. The experiments show a remarkable increase in mass transfer in curved modules as compared to conventional straight ones. Comparisons

  4. Stability of cross-linked acetic acid lignin-containing polyurethane

    Microsoft Academic Search

    Haihua WangYonghao; Yonghao Ni; M. Sarwar Jahan; Zehua Liu; Thioni Schafer

    2011-01-01

    The thermo-oxidative stability of acetic acid lignin-containing polyurethane (LPU) that contains cross-linking agents, such\\u000a as 1-aminopropyltriethoxy-silane (APTS) and\\/or trimethylolpropane (TMP) was investigated based on the thermogravimetric analysis\\u000a (TGA) method, their kinetic parameters in the thermo-oxidative process was determined. FT-IR certified the occurrence of interaction\\u000a between lignin and polyurethane (PU). It was found that continuous membrane can be formed when lignin

  5. Characterization of Cupric Glutamate Extinguishing Mechanism of Alexandrium sp. LC3 with Two-dimensional Electrophoresis and MALDI-TOF MS

    Microsoft Academic Search

    Hao Li; Jinlai Miao; Fengxia Cui; Guangyou Li

    2008-01-01

    Mechanisms by which cupric glutamate, a novel algicide, extinguishes Alexandrium sp. LC3 are shown in this study. We show that cupric glutamate not only stimulated the production of malonaldehyde (MDA)\\u000a and dramatically promoted cell plasma membrane permeability (p?p?electrophoresis (2-DE) indicated that only 47 protein\\u000a spots were detected in both control and cupric

  6. Detection of polymorphisms of human DNA by gel electrophoresis as single-strand conformation polymorphisms.

    PubMed Central

    Orita, M; Iwahana, H; Kanazawa, H; Hayashi, K; Sekiya, T

    1989-01-01

    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 by hybridization with a nick-translated DNA fragment or more clearly with RNA copies synthesized on each strand of the DNA fragment as probes. As the mobility shift caused by nucleotide substitutions might be due to a conformational change of single-stranded DNAs, we designate the features of single-stranded DNAs as single-strand conformation polymorphisms (SSCPs). Like restriction fragment length polymorphisms (RFLPs), SSCPs were found to be allelic variants of true Mendelian traits, and therefore they should be useful genetic markers. Moreover, SSCP analysis has the advantage over RFLP analysis that it can detect DNA polymorphisms and point mutations at a variety of positions in DNA fragments. Since DNA polymorphisms have been estimated to occur every few hundred nucleotides in the human genome, SSCPs may provide many genetic markers. Images PMID:2565038

  7. [Control of nanoparticles in food and biological objects. Report 2. Filtration, centrifugation, spectral methods and electrophoresis].

    PubMed

    Raspopov, R V; Gmoshinski?, I V; Popov, K I; Rykhtik, O V; Khotimchenko, S A

    2012-01-01

    The large number of the analysis methods of engineered nanoparticles and nanoobjects as a part of disperse systems on the basis of principles of a membrane filtration (micro, ultra- and a nanofiltration) ultracentrifugation, spectral methods, including dynamic and static laser light scattering, Raman light scattering, low-angle X-ray scattering, x-ray techniques, laser decomposition spectroscopy, and other methods are developed. Mass spectrometry with inductively coupled plasma can be successfully used in studying of nanomaterials chemical composition in conditions when there is additional independent information on presence of analyzed substance in a nanoscale form. Methods of electrophoresis in a supportive environment and capillary electrophoresis are beginning to be successfully applied in the study of artificial nanomaterials. However, in terms of the identification of engineered nanoparticles and nanoobjects in complex, multicomponent, heterophase systems, that the objects of the environment and, in particular, food products are, all these methods currently can't compete transmission electron microscopy and atomic force microscopy, specified for purpose of certain particular applications, features of which been described in a previous eport in detail. PMID:22888665

  8. Adaptation and tolerance of bacteria against acetic acid.

    PubMed

    Tr?ek, Janja; Mira, Nuno Pereira; Jarboe, Laura R

    2015-08-01

    Acetic acid is a weak organic acid exerting a toxic effect to most microorganisms at concentrations as low as 0.5 wt%. This toxic effect results mostly from acetic acid dissociation inside microbial cells, causing a decrease of intracellular pH and metabolic disturbance by the anion, among other deleterious effects. These microbial inhibition mechanisms enable acetic acid to be used as a preservative, although its usefulness is limited by the emergence of highly tolerant spoilage strains. Several biotechnological processes are also inhibited by the accumulation of acetic acid in the growth medium including production of bioethanol from lignocellulosics, wine making, and microbe-based production of acetic acid itself. To design better preservation strategies based on acetic acid and to improve the robustness of industrial biotechnological processes limited by this acid's toxicity, it is essential to deepen the understanding of the underlying toxicity mechanisms. In this sense, adaptive responses that improve tolerance to acetic acid have been well studied in Escherichia coli and Saccharomyces cerevisiae. Strains highly tolerant to acetic acid, either isolated from natural environments or specifically engineered for this effect, represent a unique reservoir of information that could increase our understanding of acetic acid tolerance and contribute to the design of additional tolerance mechanisms. In this article, the mechanisms underlying the acetic acid tolerance exhibited by several bacterial strains are reviewed, with emphasis on the knowledge gathered in acetic acid bacteria and E. coli. A comparison of how these bacterial adaptive responses to acetic acid stress fit to those described in the yeast Saccharomyces cerevisiae is also performed. A systematic comparison of the similarities and dissimilarities of the ways by which different microbial systems surpass the deleterious effects of acetic acid toxicity has not been performed so far, although such exchange of knowledge can open the door to the design of novel approaches aiming the development of acetic acid-tolerant strains with increased industrial robustness in a synthetic biology perspective. PMID:26142387

  9. Crystalline Membranes

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  10. Capillary Electrophoresis and Capillary Electrophoresis–Mass Spectrometry for Structural Analysis of N -Glycans Derived from Glycoproteins

    Microsoft Academic Search

    Miyako Nakano; Kazuaki Kakehi; Naoyuki Taniguchi; Akihiro Kondo

    \\u000a This chapter highlights recent developments in the analysis of proteins glycosylated of the amino groups (N) of asparagine residues (i.e., N-glycans) by capillary electrophoresis (CE) and capillary electrophoresis–mass spectrometry (CE-MS). First, the analysis of\\u000a intact glycoproteins by CE and CE-MS is reviewed. In glycoform analysis of a heterogeneous protein due to different glycosylation,\\u000a multiforms are observed on CE. Second, to

  11. Capillary electrophoresis analysis of glucooligosaccharide regioisomers.

    PubMed

    Joucla, Gilles; Brando, Thérèse; Remaud-Simeon, Magali; Monsan, Pierre; Puzo, Germain

    2004-03-01

    Complex gluco-oligosaccharide mixtures of two regioisomer series were successfully separated by CE. The gluco-oligosaccharide series were synthesized, employing a dextransucrase from Leuconostoc mesenteroides NRRL B-512F, by successive glucopyranosyl transfers from sucrose to the acceptor glucose or maltose. The glucosyl transfer to both acceptors, occurring through the formation of alpha1-->6 linkages, differed for the two series only in the glucosidic bond to the reducing end namely alpha1-->6 or alpha1-->4 bond for glucose or maltose acceptor, respectively. Thus, the combination of the two series results in mixed pairs of gluco-oligosaccharide regioisomers with different degrees of polymerization (DP). These regioisomer series were first derivatized by reductive amination with 9-aminopyrene-1,4,6-trisulfonate (APTS). Under acidic conditions using triethyl ammonium acetate as electrolyte, the APTS-gluco-oligosaccharides of each series were separated enabling unambiguous size determination by coupling CE to electrospray-mass spectrometry. However, neither these acidic conditions nor alkaline buffer systems could be adapted for the separation of the gluco-oligosaccharide regioisomers arising from the two combined series. By contrast, increased resolution was observed in an alkaline borate buffer, using differential complexation of the regioisomers with the borate anions. Such conditions were also successfully applied to the separation of glucodisaccharide regioisomers composed of alpha1-->2, alpha1-->3, alpha1-->4, and alpha1-->6 linkages commonly synthesized by glucansucrase enzymes. PMID:15004847

  12. Optimization of in-line fritless solid-phase extraction for capillary electrophoresis-mass spectrometry.

    PubMed

    Tak, Yvonne H; Toraño, Javier Sastre; Somsen, Govert W; de Jong, Gerhardus J

    2012-12-01

    In this study, in-line frit-free solid-phase extraction (SPE) has been studied for the preconcentration of analytes prior to analysis by capillary electrophoresis-mass spectrometry (CE-MS). The mixed-mode sorbent Oasis HLB was selected for the trapping of compounds of different polarity. Using 2-ethylidene-1,5-dimethyl-3,3-diphenylpirrolidine (EDDP), dihydrocodeine and codeine as test compounds, SPE parameters such as the pH of the sample and composition of the washing and elution solvent were optimized. Trapping of the analytes was optimal at pH 8.0 or higher. For efficient elution of the SPE micro column, 85% of methanol in water with 2% (v/v) acetic acid was used, which also prevented current break down in subsequent CE analysis. CE resolution of the test compounds was highest for background electrolytes (BGEs) with a pH above 8. For optimal analysis, samples were 1:1 diluted with carbonate buffer (1M, pH 8.0) prior to analysis, BGE was 60mM ammonium acetate buffer (pH 10.0), and the injected sample volume was 60 ?l (i.e., 30 capillary volumes). Good recoveries were found: 101% for EDDP, 88% for codeine and 90% for dihydrocodeine. Intraday RSDs for migration time and peak areas were below 0.56% and 15%, respectively. Peak widths at half height obtained with SPE-CE-MS were 12s for EDDP, 3.7s for dihydrocodeine and 7.4s for codeine, and were comparable to those for CE-MS. LODs were 0.22 pg/ml for EDDP, 2.1 pg/ml for dihydrocodeine and 24 pg/ml for codeine. It is concluded that the applied fritless in-line preconcentration construct proved to be highly useful for improving the sensitivity of CE while maintaining separation. PMID:22959866

  13. Eslicarbazepine acetate (BIA 2-093)

    Microsoft Academic Search

    Luis Almeida; Patrício Soares-da-Silva

    2007-01-01

    Summary  Eslicarbazepine acetate (ESL) [(S)-(?)-10-acetoxy-10, 11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide], formerly known as BIA 2-093, is a novel central nervous system (CNS)-active compound with anticonvulsant\\u000a activity. It behaves as a voltage-gated sodium channel (VGSC) blocker and is currently under clinical development for the\\u000a treatment of epilepsy and bipolar disorder. ESL shares with carbamazepine and oxcarbazepine the dibenzazepine nucleus bearing\\u000a the 5-carboxamide substitute, but is structurally

  14. Mortalin\\/GRP75 promotes release of membrane vesicles from immune attacked cells and protection from complement-mediated lysis

    Microsoft Academic Search

    David Pilzer; Zvi Fishelson

    2005-01-01

    The membrane attack complex (MAC) of the complement system is causing membrane damage and cell death. For protection, cells have adopted several resistance mechanisms, including removal of the membrane-inserted MAC by vesiculation. To identify proteins involved in MAC vesiculation, extracellular proteins released from K562 cells in response to treatment with sub-lytic complement were separated by acrylamide gel electrophoresis and protein

  15. Preparation of pervaporation membranes. Final report on Phase 1. Report for 1 January-31 October 1989

    SciTech Connect

    Baker, R.W.; Athayede, A.L.; Castro, R.

    1989-10-15

    The goal of the Phase 1 program was to prepare improved pervaporation membranes for the separation of polar solvents from water. Membranes were prepared from modified polysiloxanes and other rubbery materials. These membranes were tested with ethanol/water and ethyl acetate/water mixtures to determine their performance in a pervaporation test loop. Polydimethylsiloxane with polyamide blocks was the most selective material for ethanol/water separation. Polybutadiene membranes were preferred for ethyl acetate/water separation. The performance of the polydimethysiloxane-polyamide block copolymer demonstrates that the inclusion of hydrophilic groups into polydimethylsiloxane increases the ethanol/water selectivity, but the improvement is not significant. Testing of polyvinylmethylsiloxane membranes indicated that the degree of cross-linking in a polysiloxane membrane has a significant effect on ethanol/water selectivity. A highly cross-linked siloxane has a much lower ethanol/water selectivity than a less cross-linked material.

  16. Electrophoresis 1994, 15, 225-221 Field programming for uniform sensitivity in on-line detection in electrophoresis 225 Jason B. Shear

    E-print Network

    Zare, Richard N.

    Electrophoresis 1994, 15, 225-221 Field programming for uniform sensitivity in on-line detection in electrophoresis 225 Jason B. Shear Rajeev Dadoo Richard N. Zare Field programming to achieve uniform sensitivity for on-line detection in electrophoresis Department Of Chemistry, Stanford University, Stanford, CA Under

  17. Analytical characterization of beet root vacuole membrane

    SciTech Connect

    Marty, F.; Branton, D.

    1980-10-01

    Vacuoles from beet root (Beta vulgaris L. var. esculenta Gurke) isolated by a mechanical procedure were osmotically lysed to separate the membrane and sap components for analysis. Approximately 62% of the vacuole proteins, 70% of the nondialyzable carbohydrates and almost all of the phospholipids and sterols were recovered in the membrane fraction. The vacuole membrane had a phospholipid:protein ratio of 0.68 and a sterol:phospholipid ratio of 0.21. Seventeen complex polar lipids including phosphatides ad glycolipids have been tentatively identified. Phosphatidylcholine (54%) and phosphatidylethanolamine (24%) were the most prominant phosphoglycerides besides phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, and phosphatidic acid (1, 4, 5, and 12%, respectively. A putative sulfoglycoside and two major ceramide glycoside-like lipids, resembling those of animal lysosomes, were identified by thin-layer chromatography. High-resolution SDS-acrylamide gel electrophoresis of the polypeptides from the vacuole revealed 15 major bands with apparent molecular weights ranging from 91,000 to 12,000. Selective elution experiments delineated those polypeptides that were peripheral membrane proteins or sap proteins adsorbed to the membrane, and those that exhibited hydrophobic interaction with the lipid core. Lectin labeling results indicated that most of the polypeptides from the membrane and from the sap were glycoproteins probably of the high-mannose type characteristic of lysosomal enzymes that have undergone several stages of posttranslational modification.

  18. Phytogenic biosynthesis and emission of methyl acetate.

    PubMed

    Jardine, Kolby; Wegener, Frederik; Abrell, Leif; van Haren, Joost; Werner, Christiane

    2014-02-01

    Acetylation of plant metabolites fundamentally changes their volatility, solubility and activity as semiochemicals. Here we present a new technique termed dynamic (13) C-pulse chasing to track the fate of C1-3 carbon atoms of pyruvate into the biosynthesis and emission of methyl acetate (MA) and CO2 . (13) C-labelling of MA and CO2 branch emissions respond within minutes to changes in (13) C-positionally labelled pyruvate solutions fed through the transpiration stream. Strong (13) C-labelling of MA emissions occurred only under pyruvate-2-(13) C and pyruvate-2,3-(13) C feeding, but not pyruvate-1-(13) C feeding. In contrast, strong (13) CO2 emissions were only observed under pyruvate-1-(13) C feeding. These results demonstrate that MA (and other volatile and non-volatile metabolites) derive from the C2,3 atoms of pyruvate while the C1 atom undergoes decarboxylation. The latter is a non-mitochondrial source of CO2 in the light generally not considered in studies of CO2 sources and sinks. Within a tropical rainforest mesocosm, we also observed atmospheric concentrations of MA up to 0.6 ppbv that tracked light and temperature conditions. Moreover, signals partially attributed to MA were observed in ambient air within and above a tropical rainforest in the Amazon. Our study highlights the potential importance of acetyl coenzyme A (CoA) biosynthesis as a source of acetate esters and CO2 to the atmosphere. PMID:23862653

  19. Platinum acetate blue: synthesis and characterization.

    PubMed

    Cherkashina, Natalia V; Kochubey, Dmitry I; Kanazhevskiy, Vladislav V; Zaikovskii, Vladimir I; Ivanov, Vladimir K; Markov, Alexander A; Klyagina, Alla P; Dobrokhotova, Zhanna V; Kozitsyna, Natalia Yu; Baranovsky, Igor B; Ellert, Olga G; Efimov, Nikolai N; Nefedov, Sergei E; Novotortsev, Vladimir M; Vargaftik, Michael N; Moiseev, Ilya I

    2014-08-18

    Platinum acetate blue (PAB) of the empirical formula Pt(OOCMe)2.5±0.25, a byproduct in the synthesis of crystalline platinum(II) acetate Pt4(OOCMe)8, is an X-ray amorphous substance containing platinum in the oxidation state between (II) and (III). Typical PAB samples were studied with X-ray diffraction, differential thermal analysis-thermogravimetric, extended X-ray absorption fine structure, scanning electron microscopy, transmission electron microscopy, magnetochemistry, and combined quantum chemical density functional theory-molecular mechanics modeling to reveal the main structural features of the PAB molecular building blocks. The applicability of PAB to the synthesis of platinum complexes was demonstrated by the preparation of the new homo- and heteronuclear complexes Pt(II)(dipy)(OOCMe)2 (1), Pt(II)(?-OOCMe)4Co(II)(OH2) (2), and Pt(III)2(OOCMe)4(O3SPhMe)2 (3) with the use of PAB as starting material. PMID:25102316

  20. [Ulipristal acetate, 5mg: a new alternative].

    PubMed

    Monleón Sancho, Javier; Romaguera, Eugenia; Romero, Ainhoa; Higueras, Gema; Morcillo, Inmaculada; Fuster, Sonia

    2013-07-01

    Fibroids have a high prevalence (approaching 50%) in the female population. Although they are a benign entity, they represent a health problem of considerable magnitude, causing hemorrhaging, pain and sterility. Surgical treatment is currently safe and effective, but in recent decades numerous less invasive alternatives have appeared, such as uterine artery embolization and thermal ablation (HIFU and radiofrequency). New possibilities for medical treatment have also emerged, such as GnRh analogues, aromatase inhibitors and selective progesterone receptor modulators (SPRMs). SPRMs act through progesterone receptors and behave as agonists or antagonists in various target organs. Among them, ulipristal acetate (UA) inhibits the proliferation and induction of apoptosis and cell death pathways in leiomyoma cells, translating at the clinical level to smaller fibroids and lower uterine volumes, with no significant side effects. UA also produces amenorrhea in most patients. Randomized, phase III (PEARL I and II) clinical trials have shown the efficacy and security of UA versus placebo and leuprolide acetate (LA). UA is similar to LA, and superior to placebo in controlling bleeding and decreasing the size of the fibroid, with fewer side effects than LA. The safety and tolerance of UA have been satisfactory. UA is a reality in the preoperative treatment of fibroids, with broad potential for further development. PMID:24314567

  1. Atmospheric formic and acetic acids in Venezuela

    NASA Astrophysics Data System (ADS)

    Sanhueza, Eugenio; Figueroa, Luis; Santana, Magaly

    Gas, phase and rain concentrations of HCOOH and CH 3COOH have been measured at various sites in the savannah climatic region, a cloud forest site and a coastal site in Venezuela. Gas phase and rain water were sampled using the aqueous scrubber technique and a wet only collector, respectively. Analyses were made by ion chromatography. The results indicate that formic and acetic acids are important components of the Venezuelan atmosphere. They are homogeneously distributed, suggesting a widespread source. Boundary layer concentrations during the dry season (HCOOH, 1.8 ppbv; CH 3COOH, 1.25 ppbv) are higher than in the wet season (HCOOH, 1.0 ppbv; CH 3COOH, 0.7 ppbv), mainly due to a longer lifetime of the acid during the dry season (˜6 days) compared with the wet season (˜2 days). The overall concentrations in rain are 7.0 and 4.0 ?M for formic and acetic acids, respectively. The estimated annual total depositions are: HCOOH, 17 mmol m -2 yr -1 and CH 3COOH,10 mmol m -2 yr -1; around half of the acids are removed by dry deposition. It is established that a larger source (˜1.8 times) of both acids is present during the wet season. We speculate that atmospheric oxidation of hydrocarbons should be the main source of HCOOH and CH 3COOH in the Venezuelan atmosphere; soil emissions could make a significant contribution during the dry season.

  2. Membrane Fouling Mitigation: Membrane Cleaning

    Microsoft Academic Search

    Justin Chun-Te Lin; Duu-Jong Lee; Chihpin Huang

    2010-01-01

    Fouling is an inevitable hurdle limiting flux and performance of membrane processes. This paper reviewed the literature studies on physical cleaning methods and chemical cleaning and commented on the indices for cleaning efficiencies therein used in literature works.

  3. Plasma polymer thin film depositions to regulate gas permeability through nanoporous track etched membranes

    Microsoft Academic Search

    Christopher L. Chapman; Dhiman Bhattacharyya; Robert C. Eberhart; Richard B. Timmons; Cheng-Jen Chuong

    2008-01-01

    Deposition of thin polymeric films on nanoporous membranes is shown to provide a mechanically simple and inexpensive approach to regulate trans-membrane gas flows. For this purpose, polymeric films were deposited on polycarbonate track-etched (PCTE) membranes of 50nm and 100nm pore size. The films were generated by low-pressure glow discharge plasma polymerization of vinyl acetic acid (CH2CHCH2COOH) or perfluorohexane (n-C6F14) monomers.

  4. Phycocyanin from Chroomonas species purification, electrophoresis and isolation of subunits 

    E-print Network

    Yao, Phyllis Ping-Ching

    1981-01-01

    CH pellets, was transferred with acetone-glacial acetic a. cid (p;2, v/v) to a polyamide sheet for two-dimentional 62 thin layer chromatography with solvent systems: (1) water- 90/o formic acid (200:3, v/v) in one dimension, (2) benzene- glacial acetic... chromatography on Bio-Hex 70. The subunits of the Chroomonas phycocyanin were separated by stepwise elution from Bio-Hex 70 with increasing concentration of acid urea. The elution profile is shown in figure 9. Separation using acetic acid ? urea solution...

  5. Electrophoresis of a polyelectrolyte through a nanopore

    E-print Network

    Ghosal, S

    2006-01-01

    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.

  6. A capillary electrophoresis-based enzyme assay for kinetics and inhibition studies of carbonic anhydrase.

    PubMed

    Iqbal, Shoaib; Nisar-ur-Rahman; Iqbal, Jamshed

    2014-01-01

    In the current study, capillary electrophoresis (CE)-based enzyme assay for characterization and inhibition study of bovine carbonic anhydrase II (bCA II) was developed. The developed method is the first CE assay for carbonic anhydrase (CA). The method was optimized in order to get short analysis time, minimal sample volume consumption, and high resolution of substrate and product. The CE conditions were optimized as follows: fused-silica capillary (30 cm effective length×75 ?m i.d.), pressure injection for 5s, 20mM sodium borate buffer (pH 9.0), constant voltage of 15 kV, constant capillary temperature of 25 °C, and detection at 260 nm. For precise measurements, uridine was used as an internal standard during optimization of the CE methods. The limits of detection and quantification for p-nitrophenyl acetate (p-NPA) were 3.01 and 9.12 ?M, respectively, whereas for p-nitrophenolate they were 2.05 and 6.22 ?M, respectively. The performance of the developed method was confirmed by determination of kinetic parameters (i.e., K(m) and V(max) of bCA for p-NPA); the inhibition constant (K(i)) was determined for furosemide, a standard inhibitor of CA. The new method proved to be fast and efficient, and it can be used for the investigation of inhibitors of all isoforms of CAs. PMID:24064297

  7. Bacterial community dynamics of salted and fermented shrimp based on denaturing gradient gel electrophoresis.

    PubMed

    Han, Kook-Il; Kim, Yong Hyun; Hwang, Seon Gu; Jung, Eui-Gil; Patnaik, Bharat Bhusan; Han, Yeon Soo; Nam, Kung-Woo; Kim, Wan-Jong; Han, Man-Deuk

    2014-12-01

    The Korean traditional seafood jeotgal is consumed directly or as an additive in other foods to improve flavor or fermentation efficiency. Saeujot, made from salted and fermented tiny shrimp (SFS; Acetes japonicus), is the best-selling jeotgal in Korea. In this study, we reveal the microbial diversity and dynamics in naturally fermented shrimp by denaturing gradient gel electrophoresis (DGGE). The population fingerprints of the predominant microbiota and its succession were generated by DGGE analysis of universal V3 16S rDNA polymerase chain reaction (PCR) amplicons. Overall, 17 strains were identified from sequencing of 30 DGGE bands. The DGGE profiles showed diverse bacterial populations in the sample, throughout the fermentation of SFS. Staphylococcus equorum, Halanaerobium saccharolyticum, Salimicrobium luteum, and Halomonas jeotgali were the dominant bacteria, and their levels steadily increased during the fermentation process. Certain other bacteria, such as Psychrobacter jeotgali and Halomonas alimentaria appeared during the early-fermentation process, while Alkalibacterium putridalgicola, Tetragenococcus muriaticus, and Salinicoccus jeotgali appeared during the late-fermentation process. The members of the order Bacillales were found to be predominant during the fermentation of SFS. Furthermore, S. equorum was identified as the dominant bacterial isolate by the traditional method of culturing under aerobic and facultative anaerobic conditions. We expect that this information will facilitate the design of autochthonous starter cultures for the production of SFS with desired characteristic sensory profiles and shorter ripening times. PMID:25393163

  8. Determination of hydrazine, monomethylhydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine by nonaqueous capillary electrophoresis with amperometric detection.

    PubMed

    Guo, Lei; Matysik, Frank-Michael; Gläser, Petra; Engewald, Werner

    2005-09-01

    The present study is concerned with the application of nonaqueous capillary electrophoresis (NACE) with electrochemical detection (ED) to the separation and quantitative determination of hydrazine (Hy) and its methyl derivatives. The best performance of NACE-ED was found when using 4 mM sodium acetate/10 mM acetic acid/methanol: acetonitrile = 1:2 as the running buffer, with a bare platinum working electrode set at +1.0 V in an end-column amperometric detection cell. The choice and ratio of suitable solvents for the separation and injection media played an essential role for the performance characteristics of the method. The limits of detection for Hy, methylhydrazine, symmetrical dimethylhydrazine, and unsymmetrical dimethylhydrazine were 5, 2, 12, and 1 ng/mL, respectively. This is between one and two orders of magnitude lower than that achieved by previously reported CE-ED methods in aqueous buffer systems in conjunction with various types of chemically modified electrodes. The practical utility of the new NACE-ED methodology is demonstrated in terms of the determination of traces of Hys in spiked environmental samples containing a wide range of explosives and related compounds. PMID:16097027

  9. Sample stacking with matrix removal for the determination of paraquat, diquat and difenzoquat in water by capillary electrophoresis.

    PubMed

    Núñez, O; Moyano, E; Puignou, L; Galceran, M T

    2001-04-01

    Conditions for the simultaneous determination of paraquat, diquat and difenzoquat by capillary zone electrophoresis using a stacking technique in a chemically modified capillary have been established. To apply the stacking method with sample matrix removal for the analysis of cations, an anodic electroosmotic flow is mandatory. For quats, 50 mM acetic acid-ammonium acetate (pH 4.0) with 5% (v/v) methanol as electrophoretic buffer and the addition of 0.8 mM cetyltrimethylammonium bromide as wall capillary organic modifier was proposed. Field polarity reversal time was optimised for several sample matrices. Detection was carried out at 220 and 255 nm. Detection limits, based on a signal-to-noise ratio of 3:1, were lower than 15 microg l(-1) for standards in Milli-Q water and two to ten times higher for drinking water samples. Run-to-run and day-to-day reproducibility have been established. The method was successfully applied to the determination of the three herbicides in spiked drinking water. PMID:11330805

  10. Inexpensive and safe DNA gel electrophoresis using household materials.

    PubMed

    Ens, S; Olson, A B; Dudley, C; Ross, N D; Siddiqi, A A; Umoh, K M; Schneegurt, M A

    2012-01-01

    Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic containers are fitted with aluminum foil electrodes and 9-V batteries to run food-grade agar-agar gels using aquarium pH buffers and then stained with gentian violet. This activity was tested in a high school biology classroom with significantly positive responses on postactivity reflective surveys. The electrophoresis activity addresses several Life Science Content Standard C criteria, including aspects of cell biology, genetics, and evolution. It also can be used to teach aspects of motion and force in the physical science classroom. PMID:22615228

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

    PubMed

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

    1982-09-01

    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 was capable of precipitating 87.9% of the radioactivity associated with the hGH tracer and 86.0% of the hPRL tracer. The maximal specific binding to a liver membrane preparation averaged 67.3% of the [125I]iodo-hGH radioactivity and 48.8% of the [125I]iodo-hPRL radioactivity. The respective BA and RRA activity estimates for [125I]iodo-hGH averaged 90% and 114% of the activity measured by the RIA. For [125I]iodo-hPRL, the values were 75% by BA and 68% by RRA. The bioactivity profiles of iodinated hGH and hPRL shifted anodally on polyacrylamide gel electrophoresis in comparison to the bioactivity distribution of the respective uniodinated hormones. Iodine incorporation rather than oxidation appeared to be responsible for the shift. After electrophoresis, all eluates which contained significant radioactivity were active in the BA and RIA. Furthermore, specific activities calculated from the bioactive hormone and radioactivity in each electrophoretic segment agreed well with the average specific activity estimated from the amount of iodine incorporated into the protein peak upon gel filtration. These data suggest that hGH and hPRL to a major degree retain biological integrity after iodination. PMID:7106054

  12. Synthesis and regeneration of lead (IV) acetate

    SciTech Connect

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

    1996-11-01

    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.

  13. Ulipristal acetate: a new emergency contraceptive.

    PubMed

    Sullivan, Jade L; Bulloch, Marilyn N

    2011-07-01

    Ulipristal acetate (UPA) is a newly developed emergency contraceptive currently available in the USA and Europe. It is approved as a 30 mg one-time dose taken within 120 h (5 days) of unprotected intercourse or failed contraception. This selective progesterone receptor modulator appears to be more effective than the levonorgestrel-containing emergency contraceptive, which must be taken within 72 h of unprotected intercourse. According to pharmacodynamic trials, UPA delays follicular maturation and ovulation. In addition, UPA may modulate the endometrium. Both Phase III clinical trials found that UPA does not lose efficacy within the 120-h dosing interval. Throughout all phases of clinical studies, UPA was shown to be well tolerated with only minimal adverse drug reactions, all of which are similar to competitor therapies. PMID:22114852

  14. Leuprolide acetate treatment of catamenial pneumothorax.

    PubMed

    Garris, P D; Sokol, M S; Kelly, K; Whitman, G F; Plouffe, L

    1994-01-01

    A 35-year-old nulligravid female with a 20 pack year history of smoking and continuous OC use since age 16 presented with recurrent pneumothoraces coinciding with the onset of menses at age 28. At that time she underwent a right partial pleurectomy and lobectomy, which demonstrated bullous disease but no glandular or stromal elements. Although catamenial respiratory discomfort persisted while on OCs, no pneumothoraces were documented until age 33 at which time she was given the diagnosis of catamenial pneumothorax. A diagnostic laparoscopy failed to demonstrate endometriosis or the presence of diaphragmatic defects. In an effort to preserve her fertility, she began a course of LA-GnRH-a therapy with depot LA. Because of disabling vasomotor and emotional side effects, continuous conjugated estrogens and MPA acetate were given as add-back therapy. She has remained symptom and side effect free for over 2 years on this regimen. PMID:8293833

  15. 4-Carbamoylpiperidinium phenyl-acetate hemihydrate.

    PubMed

    Smith, Graham; Wermuth, Urs D

    2010-01-01

    The asymmetric unit of the title compound, C(6)H(13)N(2)O(+)·C(8)H(7)O(2) (-)·0.5H(2)O, comprises two isonipecotamide cations, two phenyl-acetate anions and a water mol-ecule of solvation. The hydrogen-bonding environments for both sets of ion pairs are essentially identical with the piperidinium and amide 'ends' of each cation involved in lateral heteromolecular hydrogen-bonded cyclic N-H?O associations [graph set R(2) (2)(11)] which incorporate a single carboxyl O-atom acceptor. These cyclic motifs enclose larger R(5) (5)(21) cyclic systems, forming sheet substructures which lie parallel to (101) and are linked across b by the single water mol-ecule via water O-H?O(c) (c = carboxylate) associations, giving a duplex-sheet structure. PMID:21589544

  16. 4-Carbamoylpiperidinium phenyl­acetate hemihydrate

    PubMed Central

    Smith, Graham; Wermuth, Urs D.

    2010-01-01

    The asymmetric unit of the title compound, C6H13N2O+·C8H7O2 ?·0.5H2O, comprises two isonipecotamide cations, two phenyl­acetate anions and a water mol­ecule of solvation. The hydrogen-bonding environments for both sets of ion pairs are essentially identical with the piperidinium and amide ‘ends’ of each cation involved in lateral heteromolecular hydrogen-bonded cyclic N—H?O associations [graph set R 2 2(11)] which incorporate a single carboxyl O-atom acceptor. These cyclic motifs enclose larger R 5 5(21) cyclic systems, forming sheet substructures which lie parallel to (101) and are linked across b by the single water mol­ecule via water O—H?Oc (c = carboxylate) associations, giving a duplex-sheet structure. PMID:21589544

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  18. Characteristics and Molecular Mechanism of Adhesion Proteins on Reused Hemodialysis Membranes

    Microsoft Academic Search

    Xiulin Xu; Yujing Yang; Naishuo Zhu

    2009-01-01

    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

  19. Purification of radiolabeled RNA products using denaturing gel electrophoresis

    PubMed Central

    Adachi, Hironori; Yu, Yi-Tao

    2014-01-01

    This unit discusses a basic method for purification of radiolabeled RNAs using denaturing polyacrylamide gel electrophoresis. The method consists of a number of experimental procedures, including total RNA preparation from yeast cells, isolation of a specific RNA from total yeast RNA, RNA 3' terminal labeling using nucleotide (5’[32P]pCp) addition (via ligation), denaturing (8 M urea) polyacrylamide gel electrophoresis, and RNA extraction from the gel slice. Key points for achieving good electrophoretic separation of RNA are also discussed. PMID:24510465

  20. EOS production on the Space Station. [Electrophoresis Operations/Space

    NASA Technical Reports Server (NTRS)

    Runge, F. C.; Gleason, M.

    1986-01-01

    The paper discusses a conceptual integration of the equipment for EOS (Electrophoresis Operations/Space) on the Space Station in the early 1990s. Electrophoresis is a fluid-constituent separation technique which uses forces created by an electrical field. Aspects covered include EOS equipment and operations, and Space Station installations involving a pressurized module, a resupply module, utility provisions and umbilicals and crew involvement. Accommodation feasibility is generally established, and interfaces are defined. Space Station production of EOS-derived pharmaceuticals will constitute a significant increase in capability compared to precursor flights on the Shuttle in the 1980s.

  1. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, D.; Waller, F.J.

    1999-04-06

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  2. Heterogeneous catalyst for the production of acetic anhydride from methyl acetate

    DOEpatents

    Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

    1999-01-01

    This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

  3. Membrane magic

    SciTech Connect

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

    2005-09-01

    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.

  4. Experimental study of the control of pore sizes of porous membranes applying chemicals methods

    Microsoft Academic Search

    Shumei Wang; Zhan Wang; Yang Zhang; Wenjuan Wu; Dezhong Liu; Xinmiao Zhang

    2005-01-01

    Poly(vinylidene fluoride) (PVDF), polymethyl methacrylate (PMMA) and cellulose acetate (CA) in the presence of N-methyl pyrrolidone were blended in various combinations by using dimethylformamide (DMF) and glacial acetic acid (CH3COOH) as solvent and used to prepare flat-sheet membranes by the phase-inversion process. A square-crossing table with four factors and three levels for the PVDF-PMMA-CA system was designed to study the

  5. DNA Electrophoresis on patterned Surfaces The separation of DNA molecules based on their size and mass has many applications in

    E-print Network

    Singh, Jayant K.

    DNA Electrophoresis on patterned Surfaces The separation of DNA molecules based on their size and mass has many applications in biotechnology. Traditionally gel electrophoresis and capillary electrophoresis techniques are used to separate the DNA molecules based on their molecular weight

  6. Effect of different carbon sources on membrane permeability, membrane fluidity, and fatty acid composition of a psychrotrophic Acinetobacter sp. HH1-1 during growth at low temperatures and after cold shock

    Microsoft Academic Search

    S. E. Barbaro; J. T. Trevors; W. E. Inniss

    1999-01-01

    The effect of different carbon sources on the ability of a psychrotrophic Acinetobacter sp., strain HH1-1, to grow at low temperatures and respond to cold shock was investigated by monitoring cell membrane permeability, membrane fluidity and fatty acid composition. Cells were grown in batch cultures with acetate, Tween 80 or olive oil as the sole source of carbon and incubated

  7. Biodegradable Blends of Cellulose Acetate and Starch: Production and Properties

    Microsoft Academic Search

    Jean M. Mayer; Glenn R. Elion; Charles M. Buchanan; Barbara K. Sullivan; Sheldon D. Pratt; David L. Kaplan

    1995-01-01

    Blends of cellulose acetate (2.5 degree of substitution) and starch were melt processed and evaluated for mechanical properties, biodegradability during composting, and marine and soil toxicity. Formulations containing, on a weight basis, 57% cellulose acetate (CA), 25% corn starch (St) and 19% propylene glycol (PG) had mechanical properties similar to polystyrene. Increasing plasticizer or starch content lowered tensile strength. Simulated

  8. Synthesis and characterization of cellulose acetate produced from recycled newspaper

    Microsoft Academic Search

    Guimes Rodrigues Filho; Douglas Santos Monteiro; Carla da Silva Meireles; Rosana Maria Nascimento de Assunção; Daniel Alves Cerqueira; Hernane Silva Barud; Sidney J. L. Ribeiro; Younes Messadeq

    2008-01-01

    In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48h for

  9. Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.

    ERIC Educational Resources Information Center

    Polichnowski, S. W.

    1986-01-01

    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)

  10. Anaerobic thermophilic fermentation for acetic acid production from milk permeate.

    PubMed

    Talabardon, M; Schwitzguébel, J P; Péringer, P

    2000-01-01

    Fermentation of milk permeate to produce acetic acid under anaerobic thermophilic conditions (approximately 60 degrees C) was studied. Although none of the known thermophilic acetogenic bacteria can ferment lactose, it has been found that one strain can use galactose and two strains can use lactate. Moorella thermoautotrophica DSM 7417 and M. thermoacetica DSM 2955 were able to convert lactate to acetate at thermophilic temperatures with a yield of approximately 0.93 g g(-1). Among the strains screened for their abilities to produce acetate and lactate from lactose, Clostridium thermolacticum DSM 2910 was found precisely to produce large amounts of lactate and acetate. However, it also produced significant amounts of ethanol, CO2 and H2. The lactate yield was affected by cell growth. During the exponential phase, acetate, ethanol, CO2 and H2 were the main products of fermentation with an equimolar acetate/ethanol ratio, whereas during the stationary phase, only lactic acid was produced with a yield of 4 mol per mol lactose, thus reaching the maximal theoretical value. When this bacterium was co-cultured with M. thermoautotrophica, lactose was first converted mainly to lactic acid, then to acetic acid, with a zero residual lactic acid concentration and an overall yield of acetate around 80%. Under such conditions, only 13% of the fermented lactose was converted to ethanol by C. thermolacticum. PMID:10784299

  11. Original article Ethanol and acetic-acid tolerances

    E-print Network

    Paris-Sud XI, Université de

    Original article Ethanol and acetic-acid tolerances in Drosophila melanogaster: similar maternal) Summary - Ethanol and acetic-acid tolerances were studied in a cross between 2 geo- graphic races disappeared in the F2. Further investigations demonstrated that for ethanol tolerance, the large difference

  12. Liquid-liquid equilibria of the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorene (3,5,5-trimethyl-2-cyclohexen-1-one)

    SciTech Connect

    Colombo, A.; Battilana, P.; Ragaini, V.; Bianchi, C.L. [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry] [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry; Carvoli, G. [Chemial S.p.A., Cavaglia (Italy)] [Chemial S.p.A., Cavaglia (Italy)

    1999-01-01

    Liquid-liquid equilibria for the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) were measured over the temperature range (283 to 313) K. The results were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models; experimental data were successfully reproduced. The UNIQUAC model was the most accurate in correlating the overall equilibrium composition of the studied systems. Also the NRTL model satisfactorily predicted the equilibrium composition. Isophorone experimentally resulted in a better extraction capacity for acetic acid and in a lower miscibility with water.

  13. Comprehensive Proteomic Analysis of Membrane Proteins in Toxoplasma gondii*

    PubMed Central

    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

    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

  14. Enhanced transport properties and thermal stability of agro-based RO-membrane for desalination of brackish water

    Microsoft Academic Search

    Altaf H. Basta; Houssni El-Saied

    2008-01-01

    This present work focused on preparation of economic and high performance reverse osmosis membranes, characterized by high transport properties (salt rejection and flux) towards desalination of brackish water. In this respect cellulose acetate from sugar-cane bagasse (BCA) and polymethyl methacrylate (PMMA) wastes were used as the substrates of membrane. The function of PMMA for enhancing the performance of bagasse-based cellulose

  15. Zinc, magnesium, and calcium ion supplementation confers tolerance to acetic acid stress in industrial Saccharomyces cerevisiae utilizing xylose.

    PubMed

    Ismail, Ku Syahidah Ku; Sakamoto, Takatoshi; Hasunuma, Tomohisa; Zhao, Xin-Qing; Kondo, Akihiko

    2014-12-01

    Lignocellulosic biomass is a potential substrate for ethanol production. However, pretreatment of lignocellulosic materials produces inhibitory compounds such as acetic acid, which negatively affect ethanol production by Saccharomyces cerevisiae. Supplementation of the medium with three metal ions (Zn(2+) , Mg(2+) , and Ca(2+) ) increased the tolerance of S. cerevisiae toward acetic acid compared to the absence of the ions. Ethanol production from xylose was most improved (by 34%) when the medium was supplemented with 2 mM Ca(2+) , followed by supplementation with 3.5 mM Mg(2+) (29% improvement), and 180 ?M Zn(2+) (26% improvement). Higher ethanol production was linked to high cell viability in the presence of metal ions. Comparative transcriptomics between the supplemented cultures and the control suggested that improved cell viability resulted from the induction of genes controlling the cell wall and membrane. Only one gene, FIT2, was found to be up-regulated in common between the three metal ions. Also up-regulation of HXT1 and TKL1 might enhance xylose consumption in the presence of acetic acid. Thus, the addition of ionic nutrients is a simple and cost-effective method to improve the acetic acid tolerance of S. cerevisiae. PMID:24924214

  16. Rotational electrophoresis of striped metallic microrods Klint A. Rose,1,2

    E-print Network

    Santiago, Juan G.

    Rotational electrophoresis of striped metallic microrods Klint A. Rose,1,2 John A. Meier,1 George M work on the modeling of electrophoresis of both spherical and nonspherical particles. Here we present

  17. Catalytic poly(vinyl alcohol) functionalized membranes obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Silva, A. G.; Pinto, J. V.; Ramos, A. M.; Vital, J.; Ferreira, L. M.

    2012-09-01

    Polymeric catalytic membranes bearing sulfonic acid functions have been prepared by mutual gamma irradiation at a 60Co source, of poly(vinyl alcohol) (PVA) membranes and methanesulfonic acid. The effect of various synthesis conditions on membranes' physical-chemical properties and catalytic activity in the esterification reaction between acetic acid and isoamyl alcohol to obtain isoamyl acetate (banana flavor), was evaluated. The membranes were characterized by ATR-FTIR, TPP, AFM and SEM. Water contact angle determinations were also performed. The obtained results showed that within the range of conditions studied the increase in sulfonic acid groups' content is accompanied by an enhancement in the membranes catalytic activity, while the increase in absorbed dose leads to a decrease in catalytic activity.

  18. Effect of membrane characteristics on the performance of membrane bioreactors for oily wastewater treatment.

    PubMed

    Mafirad, S; Mehrnia, M R; Sarrafzadeh, M H

    2011-01-01

    Influence of membrane material and pore size on the performance of a submerged membrane bioreactor (sMBR) for oily wastewater treatment was investigated. The sMBR had a working volume of about 19 L with flat sheet modules at the same hydrodynamic conditions. Five types of micro- and ultra-polymeric membranes containing cellulose acetate (CA), cellulose nitrate (CN), polyamide (PA), polyvinylidene difluoride (PVDF) and polyethersulfone (PES) were used and their filtration performance in terms of permeability, permeate quality and fouling intensity were evaluated. Characterization of the membranes was done by performing some analysis such as pore size distribution; contact angle and scanning electronic microscopy (SEM) microphotograph on all membranes. The quality of permeates from each membrane was identified by measuring chemical oxygen demand (COD). The results showed more irreversible fouling intensity for membranes with larger pore size which can be due to more permeation of bioparticles and colloids inside the pores. Membrane characteristics have a major role in the preliminary time of the filtration before cake layer formation so that the PA with the highest hydrophilicity had the lowest permeability decline by fouling in this period. Also, the PVDF and PES membranes had better performance according to better permeate quality in the preliminary time of the filtration related to smaller pore size and also their better fouling resistance and chemical stability properties. However, all membranes resulted in the same permeability and permeate quality after cake layer formation. An overall efficiency of about 95% in COD removal was obtained for oily wastewater treatment by the membranes used in this study. PMID:22214065

  19. Size heterogeneity of Salmonella typhimurium lipopolysaccharides in outer membranes and culture supernatant membrane fragments.

    PubMed Central

    Munford, R S; Hall, C L; Rick, P D

    1980-01-01

    Enterobacteriaceae cells growing in liquid media shed fragments of their outer membranes. These fragments, which may constitute a biologically important form of gram-negative bacterial endotoxin, have been reported to contain proteins, phospholipids, and lipopolysaccharides (LPS). In this study we compared the sizes of LPS molecules in shed membrane fragments and outer membranes from cells growing in broth cultures. Using conditional mutants of Salmonella typhimurium which incorporate specific sugars into LPS, we analyzed radiolabeled LPS by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This technique revealed that S. typhimurium LPS are more heterogeneous than previously known; molecules possessing from 0 to more than 30 O-chain repeat units were identified in outer membranes, supernatant fragments, and purified LPS. The size distributions of LPS molecules in outer membranes and supernatant fragments were similar; supernatant fragments appeared to be slightly enriched in molecules with long O-polysaccharide chains. Our results indicate the LPS molecules of many sizes are synthesized, translocated to outer membranes, and released into culture supernatants. Since the hydrophilic O-polysaccharides extend from bacterial surfaces into the aqueous environment, our findings suggest that the cell surface topography of this bacterium may be very irregular. We also speculate that heterogeneity in the degree of polymerization of O-antigenic side chains may influence the interactions of the toxic moiety of LPS (lipid A) with host constituents. Images PMID:7000751

  20. 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.

  1. Fractionation of Serum Proteins by Zone Electrophoresis in Glass Powder

    Microsoft Academic Search

    C. J. Bradish; Nan V. Smart

    1954-01-01

    IN connexion with recent electrophoretic studies of ox serum1, it became necessary to establish a reliable method for the fractionation of serum proteins which would allow numerous samples to be separated into distinct fractions of sufficient volume and concentration for subsequent physico-chemical and biological characterization. Zone electrophoresis2 appeared to be the method of choice, and the apparatus here described is

  2. SEPARATION OF GLUTEN PROTEINS BY HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High performance capillary electrophoresis (HPCE) is an analytical method that uses a voltage differential to accurately move solvents and solutes through a capillary. HPCE is a relative newcomer to the field of cereal chemistry, it utilizes small inner diameter capillaries as an anti-convective med...

  3. Sample preconcentration with chemical derivatization in capillary electrophoresis

    Microsoft Academic Search

    Adam S. Ptolemy; Philip Britz-McKibbin

    2006-01-01

    New strategies for integrating sample pretreatment with chemical analyses under a single format is required for rapid, sensitive and enantioselective analyses of low abundance metabolites in complex biological samples. Capillary electrophoresis (CE) offers a unique environment for controlling analyte\\/reagent band dispersion and electromigration properties using discontinuous electrolyte systems. Recent work in our laboratory towards developing a high-throughput CE platform for

  4. Capillary Electrophoresis Microchips for Separation and Detection of Organophosphate

    E-print Network

    Chen, Wilfred

    Capillary Electrophoresis Microchips for Separation and Detection of Organophosphate Nerve Agents system for separating and de- tecting toxic organophosphate nerve agent compounds, based on the coupling of organophosphate nerve agents. Minia- turized analytical systems (referred to as "lab-on-a-chip" devices

  5. [The purification of beta-galactosidase by flow electrophoresis].

    PubMed

    Andrienko, V I; Gorlov, Iu I; Gavrish, T G

    1990-01-01

    A plant has been constructed for the free-flow electrophoresis. It permits carrying out electrophoretic separation both in a free flow and with the use of neutral grained fillers. Beta-galactosidase has been purified from the culture liquid of the Escherichia coli cell phage lysate. Its content in the purified material amounted to 81.2 PMID:2115966

  6. Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis

    E-print Network

    Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis in supercritical fluid carbon dioxide (scCO2). Herein we demonstrate that colloids may also be stabilized in CO2 the behavior of steric stabilization in compressed supercritical fluids1-3 including carbon dioxide,4

  7. CAPILLARY ELECTROPHORESIS IMMUNOASSAY FOR 2,4-DICHLOROPHENOXYACETIC ACID

    EPA Science Inventory

    A capillary electrophoresis (CE) immunoassay format for 2,4-dichlorophenoxyacetic acid (2,4-D) is demonstrated. A fluorescent labeled 2,4-D analog competes with the analyte of interest for a finite number of binding sites provided by anti-2,4-D monoclonal antibodies. CE then pr...

  8. Lights, Camera, Action! Systematic Variation in Difference Gel Electrophoresis

    E-print Network

    Lights, Camera, Action! ­ Systematic Variation in Difference Gel Electrophoresis Kimberly F variation, including that caused by the apparatus used for imaging proteins (location of the camera). The conventional 2DE method is attractive because of its resolving power, sensitivity, and the low equipment cost

  9. Capillary electrophoresis application in metal speciation and complexation characterization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Capillary electrophoresis is amenable to the separation of metal ionic species and the characterization of metal-ligand interactions. This book chapter reviews and discusses three representative case studies in applications of CE technology in speciation and reactions of metal with organic molecules...

  10. odium dodecyl sulfate polyacry-lamide gel electrophoresis (SDS-

    E-print Network

    Lebendiker, Mario

    been attributed to three innovations that permit- ted the correlation of electrophoretic mobil- ity) and reducing agents to denature pro- teins (7). SDS binds strongly to proteins at an approximate ratio of 1-Cl 10 inNovations 13 Preparation of protein samples for SDS-polyacrylamide gel electrophoresis

  11. Gel Electrophoresis--The Easy Way for Students

    ERIC Educational Resources Information Center

    VanRooy, Wilhelmina; Sultana, Khalida

    2010-01-01

    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…

  12. Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S.

    1984-01-01

    Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

  13. Improving the expression of recombinant proteins in E. coli BL21 (DE3) under acetate stress: an alkaline pH shift approach.

    PubMed

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

    2014-01-01

    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

  14. Hemodialysis membranes for acute and chronic renal insufficiency.

    PubMed

    Yu, Jin-Gang; Yu, Lin-Yan; Jiang, Xin-Yu; Chen, Xiao-Qing; Tao, Li-Jian; Jiao, Fei-Peng

    2013-08-01

    As an incomplete renal replacement for the patients with either acute or chronic renal failure, membrane-based hemodialysis therapy is progressing rapidly. However, the mortality and morbidity remain unacceptably high. Much effort has been put into improving the biocompatibility of the hemodialysis membranes. To effectively remove small solutes and 'middle molecules' in compact cartridges, the hydraulic and permselective properties of the hemodialysis membranes have also been deeply investigated. An overview of recent progress of different kinds of hemodialysis membranes and their preparation technology, as well as their modification techniques, is presented. The advantages and deficiencies of many synthetic membranes, including cellulose, cellulose acetate (CA), chitosan (CS), polysulfone (PS), poly(ether sulfone) (PES), polyacrylonitrile (PAN), ethylene-vinyl alcohol copolymer (EVOH), poly (methyl methacrylate) (PMMA) and poly(vinyl alcohol) (PVA), etc. are elaborated upon. PMID:23782098

  15. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  16. Characterization of polyanionprotein complexes by frontal analysis continuous capillary electrophoresis and small angle

    E-print Network

    Dubin, Paul D.

    electrophoresis and small angle neutron scattering: Effect of polyanion flexibility Toshiaki Hattori was measured by frontal analysis continuous capillary electrophoresis at pH values above the isoelectric point electrophoresis; Persistence length; Complex formation The elucidation of the interaction between proteins

  17. A model for Joule heating-induced dispersion in microchip electrophoresis

    E-print Network

    Lin, Qiao

    A model for Joule heating-induced dispersion in microchip electrophoresis Yi Wang,a Qiao Lin processes that commonly occur in microchip electrophoresis. This model, which is given in terms microfluidic components, microchip electrophoresis is a key technology to enable lab-on-a-chip microsystems

  18. Induced-charge electrophoresis near a wall Mustafa Sabri Kilic1

    E-print Network

    Bazant, Martin Z.

    Induced-charge electrophoresis near a wall Mustafa Sabri Kilic1 and Martin Z. Bazant1,2,3 1-charge electrophoresis (ICEP) has mostly been analyzed for asymmetric particles in an infinite fluid, but channel walls of this phenomenon. I. INTRODUCTION Most theoretical work on electrophoresis has focused on spherical particles

  19. HiTRACE-Web: an online tool for robust analysis of high-throughput capillary electrophoresis

    E-print Network

    Das, Rhiju

    HiTRACE-Web: an online tool for robust analysis of high-throughput capillary electrophoresis Hanjoo-scale high- throughput capillary electrophoresis data, we previ- ously proposed a suite of efficient analysis software named HiTRACE (High Throughput Robust Analysis of Capillary Electrophoresis). HiTRACE has been

  20. Peak-Shape Correction to Symmetry for Pressure-Driven Sample Injection in Capillary Electrophoresis

    E-print Network

    Krylov, Sergey

    Peak-Shape Correction to Symmetry for Pressure-Driven Sample Injection in Capillary Electrophoresis Supporting Information ABSTRACT: Pressure-driven sample injection in capillary electrophoresis results. The back side, on the other hand, has a flat interface with the electrophoresis run buffer. Here, we

  1. Capillary Electrophoresis Frontal Analysis for Characterization of rv 3 Integrin Binding

    E-print Network

    Chen, David D.Y.

    Capillary Electrophoresis Frontal Analysis for Characterization of rv 3 Integrin Binding with capil- lary electrophoresis-frontal analysis method. The new algorithm used to calculate the binding), surface plasmon resonance (SPR), and capillary electrophoresis (CE).1-5 CE has many advantages over other

  2. Analysis by Capillary Electrophoresis of the Kinetics of Charge Ladder Formation for Bovine

    E-print Network

    Prentiss, Mara

    Analysis by Capillary Electrophoresis of the Kinetics of Charge Ladder Formation for Bovine were synthesized and the relative abundances of the rungs analyzed by capillary electrophoresis by capillary electrophoresis (CE).5-7 In synthesizing charge ladders by acetylating various proteins, we have

  3. Particle electrophoresis and dielectrophoresis in curved microchannels Junjie Zhu, Xiangchun Xuan *

    E-print Network

    Xuan, Xiangchun "Schwann"

    Particle electrophoresis and dielectrophoresis in curved microchannels Junjie Zhu, Xiangchun Xuan: Electrophoresis Microchannel Curvature Dielectrophoresis Focusing a b s t r a c t Studies of particle electrophoresis have so far been limited to primarily theoretical or numerical analyses in straight microchannels

  4. Stabilization of a suspension of sedimenting rods by induced-charge electrophoresis

    E-print Network

    Shaqfeh, Eric

    Stabilization of a suspension of sedimenting rods by induced-charge electrophoresis David to concentration fluctuations when no field is applied, we show that the induced-charge electrophoresis by electrophoresis.1 More pre- cisely, a particle with a fixed surface charge attracts counte- rions, which

  5. Quantitative assay for epinephrine in dental anesthetic solutions by capillary electrophoresis

    E-print Network

    Chen, David D.Y.

    Quantitative assay for epinephrine in dental anesthetic solutions by capillary electrophoresis in capillary electrophoresis. The concentration detection limit for epinephrine is about 5.0 3 1027 M (90 ng ml, linearity, accuracy and specificity. Keywords: Capillary electrophoresis; epinephrine; dental anesthetic

  6. 496 Anal. Chem. 1990, 62,496-503 Interaction of Capillary Zone Electrophoresis with a Sheath

    E-print Network

    Chen, David D.Y.

    496 Anal. Chem. 1990, 62,496-503 Interaction of Capillary Zone Electrophoresis with a Sheath Flow mobilitlesmay be measured wlth good accuracy. The low flow rate of capillary zone electrophoresis affects radial diffusion. Capillary zone electrophoresis is a particularly powerful technique for the analysis

  7. Velocity-Difference Induced Focusing of Nucleotides in Capillary Electrophoresis with a

    E-print Network

    Chen, David D.Y.

    Articles Velocity-Difference Induced Focusing of Nucleotides in Capillary Electrophoresis focusing (V-DIF) of nucleo- tides was achieved by using a dynamic pH junction in capillary electrophoresis. A homogeneous electrolyte system is often used for capillary electrophoresis (CE) separations in which analyte

  8. Kinetic capillary electrophoresis separates compounds in a bind [February 19, 2006

    E-print Network

    Krylov, Sergey

    Kinetic capillary electrophoresis separates compounds in a bind [February 19, 2006] A team of Canadian chemists has come up with a new way of using capillary electrophoresis (CE) to study biomolecular electrophoresis variant, which they have termed Kinetic CE (KCE), by accident, when they realised that two newly

  9. Surface characterization of poly(ethylene glycol) coated human red blood cells by particle electrophoresis.

    PubMed

    Neu, Björn; Armstrong, Jonathan K; Fisher, Timothy C; Meiselman, Herbert J

    2003-01-01

    Recent studies have shown that the covalent attachment of poly(ethylene glycol), abbreviated as PEG, to the surface of human red blood cells (RBC) leads to masking of membrane antigenic sites and inhibition of RBC aggregation. The effects of PEG coating on the regions near the RBC glycocalyx were thus explored using cell micro-electrophoresis. Both linear (3.35, 18.5, 35.0) and an 8-arm 35.9 kDa reactive PEG were used; in one series, thick cross-linked coats were obtained using a branched PEG amine as a cross-linker. The results indicate marked decreases of RBC mobility (up to 90%) which were affected by polymer molecular mass and geometry. Since PEG is neutral and its covalent attachment is predominantly to primary amine groups, such decreases of mobility most likely reflect structural changes near and within the RBC glycocalyx rather than decreased surface charge density. Experimental data were analyzed using a theoretical approach which allows calculation of the thickness and friction of the polymer layers: (1) for linear PEGs, thickness increased and friction decreased with polymer mass; (2) compared to linear PEGs of similar molecular mass, thickness was less and friction was greater for the branched PEG; (3) cross-linked PEG coatings were more than 50 nm thick and were insensitive to changes of ionic strength. These observations are consistent with the aggregation behavior of PEG-coated RBC and indicate the usefulness of micro-electrophoresis methods for studies of covalently-attached polymers: the resulting calculated thickness and friction factors should be of value in achieving desired cellular surface characteristics or levels of cell-cell interaction. PMID:12775912

  10. Pharmacokinetics and drug interactions of eslicarbazepine acetate.

    PubMed

    Bialer, Meir; Soares-da-Silva, Patricio

    2012-06-01

    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

  11. Eslicarbazepine acetate for partial-onset seizures.

    PubMed

    Rauchenzauner, Markus; Luef, Gerhard

    2011-12-01

    Eslicarbazepine acetate (ESL), a new voltage-gated sodium channel blocker that is chemically related to carbamazepine and partially metabolized to oxcarbazepine, has attracted attention as results of previous Phase II and III studies demonstrated and confirmed efficacy and tolerability of ESL 800 and 1200 mg once daily as add-on therapy for adult patients with drug-resistant partial-onset seizures. In children, efficacy data point towards a dose-dependent decrease in seizure frequency and tolerability analyses showed a low incidence of mild drug-related adverse effects at 5 and 15 mg/kg/day. The most frequently reported adverse effects were dizziness, somnolence, headache, diplopia, nausea and vomiting. The convenience of once-daily dosing and a short/simple titration regimen in combination with a comparative efficacy and tolerability profile might promote ESL as a valid alternative to the current adjunctive antiepileptic drug therapy armamentarium for drug-resistant partial seizures in adults. Since clinical trials in children and adolescents on ESL efficacy and safety are ongoing and data already published are far from conclusive, the therapeutic value of ESL in this special population has to be established in the near future. PMID:22091592

  12. Emergency contraception: potential role of ulipristal acetate.

    PubMed

    Gemzell-Danielsson, Kristina; Meng, Chun-Xia

    2010-01-01

    Unintended pregnancy is a global reproductive health problem. Emergency contraception (EC) provides women with a safe means of preventing unwanted pregnancies after having unprotected intercourse. While 1.5 mg of levonorgestrel (LNG) as a single dose or in 2 doses with 12 hours apart is the currently gold standard EC regimen, a single dose of 30 mg ulipristal acetate (UPA) has recently been proposed for EC use up to 120 hours of unprotected intercourse with similar side effect profiles as LNG. The main mechanism of action of both LNG and UPA for EC is delaying or inhibiting ovulation. However, the 'window of effect' for LNG EC seems to be rather narrow, beginning after selection of the dominant follicular and ending when luteinizing hormone peak begins to rise, whereas UPA appears to have a direct inhibitory effect on follicular rupture which allows it to be also effective even when administered shortly before ovulation, a time period when use of LNG is no longer effective. These experimental findings are in line with results from a series of clinical trials conducted recently which demonstrate that UPA seems to have higher EC efficacy compared to LNG. This review summarizes some of the data available on UPA used after unprotected intercourse with the purpose to provide evidence that UPA, a new type of second-generation progesterone receptor modulator, represents a new evolutionary step in EC treatment. PMID:21072297

  13. PHA based denitrification: municipal wastewater vs. acetate.

    PubMed

    Krasnits, Eli; Beliavsky, Michael; Tarre, Sheldon; Green, Michal

    2013-03-01

    Denitrification of municipal wastewater based on bacterial storage polymers-Polyhydroxyalkanoates (PHA) - was investigated in biofilm sequencing batch reactors, as a part of a two sludge system for wastewater treatment and in comparison to acetate based synthetic wastewater. The results show that PHA based denitrification (PBD) of real wastewater can be a viable alternative, especially for wastewater with low COD/N ratio, without the need for external carbon source addition. High nitrate removal capacity of about 40-50 mg N/L with a low COD/N requirement of about 4-5, were observed. It was found that entrapped particulate organic matter contributed additional reducing power, on top of the storage materials, thus allowing for the high nitrate reduction capacity. Daily removal rates were similar to those of extensive treatment systems (0.24-0.31 gr N/L reactor*d). Large differences in storage yield and composition between biomass grown on synthetic and municipal wastewater were observed. PMID:23395755

  14. Polyvinyl acetate-based film coatings.

    PubMed

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

    2013-12-01

    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

  15. 40 CFR 180.1258 - Acetic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Acetic acid; exemption from the requirement...From Tolerances § 180.1258 Acetic acid; exemption from the requirement...residues of the biochemical pesticide acetic acid when used as a...

  16. 40 CFR 180.1258 - Acetic acid; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Acetic acid; exemption from the requirement...From Tolerances § 180.1258 Acetic acid; exemption from the requirement...residues of the biochemical pesticide acetic acid when used as a...

  17. Regulation of urokinase receptors in monocytelike U937 cells by phorbol ester phorbol myristate acetate.

    PubMed

    Picone, R; Kajtaniak, E L; Nielsen, L S; Behrendt, N; Mastronicola, M R; Cubellis, M V; Stoppelli, M P; Pedersen, S; Danø, K; Blasi, F

    1989-02-01

    A specific surface receptor for urokinase plasminogen activator (uPA) recognizes the amino-terminal growth factor-like sequence of uPA, a region independent from and not required for the catalytic activity of this enzyme. The properties of the uPA receptor (uPAR) and the localization and distribution of uPA in tumor cells and tissues suggest that the uPA/uPAR interaction may be important in regulating extracellular proteolysis-dependent processes (e.g., invasion, tissue destruction). Phorbol myristate acetate (PMA), an inducer of U937 cell differentiation to macrophage-like cells, elicits a time- and concentration-dependent increase in the number of uPAR molecules as shown by binding, cross-linking, and immunoprecipitation studies. The effect of PMA is blocked by cycloheximide. Overall, the data indicate that PMA increases the synthesis of uPA. PMA treatment also causes a decrease in the affinity of the uPAR for uPA, thus uncovering another way of regulating the interaction between uPA and uPAR. In addition, the PMA treatment causes a modification of migration of the cross-linked receptor in mono- and bidimensional gel electrophoresis. PMID:2537321

  18. Computerized image analysis for acetic acid induced intraepithelial lesions

    NASA Astrophysics Data System (ADS)

    Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

    2008-03-01

    Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

  19. Crystal structure of a mixed solvated form of amoxapine acetate

    PubMed Central

    Bhardwaj, Rajni M.; Raval, Vishal; Oswald, Iain D. H.; Florence, Alastair J.

    2015-01-01

    The mixed solvated salt 4-(2-chloro­dibenzo[b,f][1,4]oxazepin-11-yl)piperazin-1-ium acetate–acetic acid–cyclo­hexane (2/2/1), C17H17ClN3O+·C2H3O2 ?·C2H4O2·0.5C6H12, crystallizes with one mol­ecule of protonated amoxapine (AXPN), an acetate anion and a mol­ecule of acetic acid together with half a mol­ecule of cyclo­hexane. In the centrosymmetric crystal, both enanti­omers of the protonated AXPN mol­ecule stack alternatively along [001]. Acetate anions connect the AXPN cations through N—H?O hydrogen bonding in the [010] direction, creating a sheet lying parallel to (100). The acetic acid mol­ecules are linked to the acetate anions via O—H?O hydrogen bonds within the sheets. Within the sheets there are also a number of C—H?O hydrogen bonds present. The cyclo­hexane solvent mol­ecules occupy the space between the sheets. PMID:25878802

  20. Perspectives for the biotechnological production of ethyl acetate by yeasts.

    PubMed

    Löser, Christian; Urit, Thanet; Bley, Thomas

    2014-06-01

    Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester. PMID:24788328

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

    E-print Network

    Pace, Hudson 1982-

    2012-11-28

    The motivation of this work was to produce novel analytical techniques capable of probing the physical properties of the cell surface. Many researchers have used supported lipid bilayers (SLBs) as models to study the ...

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

    E-print Network

    Pace, Hudson 1982-

    2012-11-28

    (Figure 2).22 To do this, an initial bilayer (shown in blue) was formed at the liquid/solid interface using a 1 mg/ml solution of 100 nm diameter vesicles within the confines of a polydimethylsiloxane (PDMS, Sylgard 184, Dow Corning, Midland, MI) well... on a clean glass coverslip. The vesicles, which were made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC, Avanti Polar Lipids, Alabaster, AL), were incubated over the surface for at least 10 minutes before being washed away with fresh Tris...

  3. SAGA complex components and acetate repression in Aspergillus nidulans.

    PubMed

    Georgakopoulos, Paraskevi; Lockington, Robin A; Kelly, Joan M

    2012-11-01

    Alongside the well-established carbon catabolite repression by glucose and other sugars, acetate causes repression in Aspergillus nidulans. Mutations in creA, encoding the transcriptional repressor involved in glucose repression, also affect acetate repression, but mutations in creB or creC, encoding components of a deubiquitination system, do not. To understand the effects of acetate, we used a mutational screen that was similar to screens that uncovered mutations in creA, creB, and creC, except that glucose was replaced by acetate to identify mutations that were affected for repression by acetate but not by glucose. We uncovered mutations in acdX, homologous to the yeast SAGA component gene SPT8, which in growth tests showed derepression for acetate repression but not for glucose repression. We also made mutations in sptC, homologous to the yeast SAGA component gene SPT3, which showed a similar phenotype. We found that acetate repression is complex, and analysis of facA mutations (lacking acetyl CoA synthetase) indicates that acetate metabolism is required for repression of some systems (proline metabolism) but not for others (acetamide metabolism). Although plate tests indicated that acdX- and sptC-null mutations led to derepressed alcohol dehydrogenase activity, reverse-transcription quantitative real-time polymerase chain reaction showed no derepression of alcA or aldA but rather elevated induced levels. Our results indicate that acetate repression is due to repression via CreA together with metabolic changes rather than due to an independent regulatory control mechanism. PMID:23173087

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

    PubMed

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

    2011-08-01

    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

  5. Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism

    DOEpatents

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

    1992-12-22

    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. 3 figs.

  6. Lipid membranes for membrane proteins.

    PubMed

    Kukol, Andreas

    2015-01-01

    The molecular dynamics (MD) simulation of membrane proteins requires the setup of an accurate representation of lipid bilayers. This chapter describes the setup of a lipid bilayer system from scratch using generally available tools, starting with a definition of the lipid molecule POPE, generation of a lipid bilayer, energy minimization, MD simulation, and data analysis. The data analysis includes the calculation of area and volume per lipid, deuterium order parameters, self-diffusion constant, and the electron density profile. PMID:25330959

  7. Release characteristics of quinupramine from the ethylene-vinyl acetate matrix.

    PubMed

    Kim, Jin; Kim, Woong-Jang; Kim, Seong-Jin; Cho, Cheong-Weon; Shin, Sang-Chul

    2006-06-01

    An ethylene-vinyl acetate (EVA) matrix containing quinupramine was prepared in an attempt to develop a controlled delivery system for quinupramine. Permeation studies of quinupramine through the EVA copolymer membrane were carried out using a two-chamber diffusion cell. The rate of drug permeation through the EVA membrane was proportional to the PEG 400 volume fraction. The release of quinupramine from the EVA matrix was examined using a modified Franz diffusion cell. A plasticizer was added to prepare the pore structure of the EVA matrix in order to increase the rate of drug release. The effects of PEG 400, membrane thickness, drug concentration, temperature, and plasticizer on drug release rate were investigated. The drug release rate from the EVA matrix increased with increasing PEG 400 volume fraction, temperature and drug loading dose. The activation energy for drug release was 5.91, 5.39, 4.68 and 4.52 kcal/mol for a loading dose of 0.5%, 1%, 1.5%, and 2%, respectively. Among the plasticizers used, diethyl phthalate showed the best results. The release of quinupramine from the EVA matrix follows a diffusion-controlled model, where the quantity released per unit area is proportional to the square root of time. The controlled release of quinupramine was achieved using the EVA polymer including a plasticizer. PMID:16644151

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

    PubMed Central

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

    2013-01-01

    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

  9. Agarose gel electrophoresis for the separation of DNA fragments.

    PubMed

    Lee, Pei Yun; Costumbrado, John; Hsu, Chih-Yuan; Kim, Yong Hoon

    2012-01-01

    Agarose gel electrophoresis is the most effective way of separating DNA fragments of varying sizes ranging from 100 bp to 25 kb(1). Agarose is isolated from the seaweed genera Gelidium and Gracilaria, and consists of repeated agarobiose (L- and D-galactose) subunits(2). During gelation, agarose polymers associate non-covalently and form a network of bundles whose pore sizes determine a gel's molecular sieving properties. The use of agarose gel electrophoresis revolutionized the separation of DNA. Prior to the adoption of agarose gels, DNA was primarily separated using sucrose density gradient centrifugation, which only provided an approximation of size. To separate DNA using agarose gel electrophoresis, the DNA is loaded into pre-cast wells in the gel and a current applied. The phosphate backbone of the DNA (and RNA) molecule is negatively charged, therefore when placed in an electric field, DNA fragments will migrate to the positively charged anode. Because DNA has a uniform mass/charge ratio, DNA molecules are separated by size within an agarose gel in a pattern such that the distance traveled is inversely proportional to the log of its molecular weight(3). The leading model for DNA movement through an agarose gel is "biased reptation", whereby the leading edge moves forward and pulls the rest of the molecule along(4). The rate of migration of a DNA molecule through a gel is determined by the following: 1) size of DNA molecule; 2) agarose concentration; 3) DNA conformation(5); 4) voltage applied, 5) presence of ethidium bromide, 6) type of agarose and 7) electrophoresis buffer. After separation, the DNA molecules can be visualized under uv light after staining with an appropriate dye. By following this protocol, students should be able to: Understand the mechanism by which DNA fragments are separated within a gel matrix Understand how conformation of the DNA molecule will determine its mobility through a gel matrix Identify an agarose solution of appropriate concentration for their needs Prepare an agarose gel for electrophoresis of DNA samples Set up the gel electrophoresis apparatus and power supply Select an appropriate voltage for the separation of DNA fragments Understand the mechanism by which ethidium bromide allows for the visualization of DNA bands Determine the sizes of separated DNA fragments. PMID:22546956

  10. Experimental and theoretical investigation of diffusion processes in a membrane anaerobic reactor for bio-hydrogen production

    Microsoft Academic Search

    Hang Zheng; Cathryn O’Sullivan; Ram Mereddy; Raymond J. Zeng; Mikel Duke; William P. Clarke

    2010-01-01

    This paper explores the potential for advanced membranes to act as a sink for hydrogen generated during anaerobic digestion thereby maintaining very low hydrogen concentrations and more favorable conditions for fermentative and possibly acetate oxidative pathways. This necessitates that the membranes function when submerged in water.Permeation of hydrogen through submerged membranes was measured at fluxes of 1.31×10?9molm?2s?1Pa?1, and 74.1×10?9molm?2s?1Pa?1 for

  11. Water dispersible microbicidal cellulose acetate phthalate film

    PubMed Central

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

    2003-01-01

    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

  12. Peroxisome subpopulations of the rat liver. Isolation by immune free flow electrophoresis.

    PubMed

    Völkl, A; Mohr, H; Fahimi, H D

    1999-09-01

    Peroxisomes (POs) are a heterogenous population of cell organelles which, in mammals, are most abundant in liver and kidney. Although they are usually isolated by differential and density gradient centrifugation, isolation is hampered by their high fragility, sensitivity to mechanical stress, and their sedimentation characteristics, which are close to those of other major organelles, particularly microsomes. Consequently, until now only the so-called "heavy" POs with a buoyant density of 1.22-1.24 g/cm(3) have been highly purified from rat liver, whereas the other subpopulations also present in that tissue have escaped adequate characterization. The purification of these subpopulations has become an essential task in view of the functional significance of POs in humans, and the putative importance of peroxisomal subpopulations in the biogenesis of this organelle. Here we used an alternative novel approach to density gradient centrifugation, called immune free flow electrophoresis (IFFE). IFFE combines the advantages of electrophoretic separation with the high selectivity of an immune reaction. It makes use of the fact that the electrophoretic mobility of a subcellular particle complexed to an antibody against the cytoplasmic domain of one of its integral membrane proteins is greatly diminished, provided that the pH of the electrophoresis buffer is adjusted to pH approximately 8.0, the pI of IgG molecules. Because of this reduced electrophoretic mobility, IgG-coupled particles can be separated in an electric field from those that are noncoupled and hence more mobile. The IFFE technique has been recently applied for isolation of regular POs (rho = 1.22-1.24 g/cm(3)) from a light mitochondrial fraction of rat liver. We succeeded in isolating different subpopulations of POs by applying IFFE to heavy, light, and postmitochondrial fractions separated by differential centrifugation of a rat liver homogenate. The PO subfractions obtained differed in their composition of matrix and membrane proteins, as revealed by immunoblotting. This indicates that they indeed represent distinct subpopulations of rat hepatic POs. PMID:10449531

  13. Applications of space-electrophoresis in medicine. [for cellular separations in molecular biology

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1976-01-01

    The nature of electrophoresis is reviewed and potential advances realizable in the field of biology and medicine from a space electrophoresis facility are examined. The ground-based applications of electrophoresis: (1) characterization of an ionized species; (2) determination of the quantitative composition of a complex mixture; and (3) isolation of the components of a mixture, separation achieved on the basis of the difference in transport rates is reviewed. The electrophoresis of living cells is considered, touching upon the following areas: the separation of T and B lymphocytes; the genetic influence on mouse lymphocyte mobilities; the abnormal production of specific and monoclonal immunoproteins; and the study of cancer. Schematic diagrams are presented of three types of electrophoresis apparatus: the column assembly for the static electrophoresis experiment on the Apollo-Soyuz mission, the continuous flow apparatus used in the same mission and a miniaturized electrophoresis apparatus.

  14. Lipopolymer gradient diffusion in supported bilayer membranes

    PubMed Central

    Zhang, Huai-Ying; Hill, Reghan J.

    2011-01-01

    We measure the gradient diffusion coefficient of a model lipopolymer in supported lipid bilayer membranes from Fourier-transform post-electrophoresis relaxation. The experiments and accompanying quantitative interpretation furnish the concentration dependence of the gradient diffusion coefficient. In striking contrast to the recent measurements of the self-diffusion coefficient from fluorescence recovery after photobleaching, the lipopolymer gradient diffusion coefficient increases with concentration. We interpret the enhancement at small but finite concentrations using the Scalettar–Abney–Owicki (SAO) statistical mechanical theory (1988) and the Bussell–Koch–Hammer (BKH) hydrodynamic theory (1995), which are customarily adopted to model membrane protein dynamics. The SAO theory furnishes an effective disc radius and soft repulsive interaction radius that are comparable to the Flory radius of the unperturbed polyethylene glycol chains. On the other hand, the BKH theory predicts a gradient diffusion coefficient that decreases with disc/membrane protein concentration. Thus, in contrast to membrane proteins, we conclude that lipopolymer hydrodynamic interactions are weak because the principal disturbances are in the low-viscosity aqueous phase. Accordingly, lipopolymer interactions are dominated by thermodynamic interactions among polymer chains. Interestingly, our experiments suggest that increasing (decreasing) the polymer molecular weight should increase (decrease) the relaxation rate of lipopolymer concentration fluctuations. PMID:20702448

  15. Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide

    PubMed Central

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  16. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    PubMed

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

  17. Cosolvent gel-like materials from partially hydrolyzed poly(vinyl acetate)s and borax.

    PubMed

    Angelova, Lora V; Terech, Pierre; Natali, Irene; Dei, Luigi; Carretti, Emiliano; Weiss, Richard G

    2011-09-20

    A gel-like, high-viscosity polymeric dispersion (HVPD) based on cross-linked borate, partially hydrolyzed poly(vinyl acetate) (xPVAc, where x is the percent hydrolysis) is described. Unlike hydro-HVPDs prepared from poly(vinyl alcohol) (PVA) and borate, the liquid portion of these materials can be composed of up to 75% of an organic cosolvent because of the influence of residual acetate groups on the polymer backbone. The effects of the degree of hydrolysis, molecular weight, polymer and cross-linker concentrations, and type and amount of organic cosolvent on the rheological and structural properties of the materials are investigated. The stability of the systems is explored through rheological and melting-range studies. (11)B NMR and small-angle neutron scattering (SANS) are used to probe the structure of the dispersions. The addition of an organic liquid to the xPVAc-borate HVPDs results in a drastic increase in the number of cross-linked borate species as well as the agglomeration of the polymer into bundles. These effects result in an increase in the relaxation time and thermal stability of the networks. The ability to make xPVAc-borate HVPDs with very large amounts of and rather different organic liquids, with very different rheological properties that can be controlled easily, opens new possibilities for applications of PVAc-based dispersions. PMID:21848256

  18. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    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.

  19. Hereditary red cell membrane disorders and laboratory diagnostic testing.

    PubMed

    King, M-J; Zanella, A

    2013-06-01

    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

  20. Permeation study of five formulations of alpha-tocopherol acetate through human cadaver skin.

    PubMed

    Mahamongkol, Hansa; Bellantone, Robert A; Stagni, Grazia; Plakogiannis, Fotios M

    2005-01-01

    Alpha-tocopherol (AT) is the vitamin E homologue with the highest in vivo biological activity. AT protects against the carcinogenic and mutagenic activity of ionizing radiation and chemical agents, and possibly against UV-induced cutaneous damage. For stability consideration, alpha-tocopherol is usually used as its prodrug ester, alpha-tocopherol acetate (ATA), which once absorbed into the skin is hydrolyzed to alpha-tocopherol, the active form. The objective of this research was to characterize in vitro the permeation properties of ATA from various solutions and gel formulations. Permeation studies were conducted using modified Franz diffusion cells and human cadaver skin as the membrane. Specifically, 5% (w/w) alpha-tocopherol acetate was formulated in the following vehicles: ethanol, isopropyl myristate, light mineral oil, 1% Klucel gel in ethanol, and 3% Klucel gel in ethanol (w/w). The receiver temperature was 37 degrees C. Samples from the receiver were collected at 2, 4, 6, 8, 12, 24, 30, 36, and 48 hours and analyzed by HPLC for concentrations of alpha-tocopherol acetate and alpha-tocopherol. The permeabilities of ATA through human cadaver skin were 1.0x10(-4), 1.1x10(-2), 1.4x10(-4), 2.1x10(-4), and 4.7x10(-4) cm/h for the ethanol solution, isopropyl myristate solution, light mineral oil solution, 1% Klucel gel, and 3% Klucel gel, respectively. The results show that the formulation had relatively minor effects on the permeability coefficients of ATA through cadaver skin in all cases except for the isopropyl myristate solution. PMID:15868062

  1. Miscibility studies on blends of cellulose acetate and nylon 6

    Microsoft Academic Search

    G. M Shashidhara; K. H Guruprasad; A Varadarajulu

    2002-01-01

    Miscibility studies on cellulose secondary acetate(CA)\\/Nylon 6(N6) blends have been carried out in this work. Dilute solution viscometry for the blend solutions using formic acid as the common solvent shows the existence of miscibility window.

  2. Extruding foams from corn starch acetate and native corn starch.

    PubMed

    Guan, Junjie; Hanna, Milford A

    2004-01-01

    Because of the hydrophilic characteristics of native starch foams and the cost of modifying starch, the uses of starch and modified starch foams are hindered. To decrease hydrophilicity and cost of starch foams, native corn starch was blended with starch acetate and extruded. A twin-screw mixing extruder was used to produce the foams. Native starch content, screw speed, and barrel temperature had significant effects on molecular degradation of starches during extrusion. The melting temperature of extruded starch acetate/native starch foam was higher (216 degrees C) than that for starch acetate (193.4 degrees C). Strong peaks in the X-ray diffractograms of extruded starch acetate/native starch foam suggested new crystalline regions were formed. Optimum conditions for high radial expansion ratio, high compressibility, low specific mechanical energy requirement, and low water absorption index were 46.0% native starch content, 163 rpm screw speed, and 148 degrees C barrel temperature. PMID:15530049

  3. Electronic interactions between gold films and mn12-acetate

    E-print Network

    Means, Joel Lewis

    2009-05-15

    Interactions between Mn12–acetate molecular magnets and thin gold films have been explored in light of the theory of weak localization. Low-temperature measurements of the magnetoresistance of gold films of varying thicknesses, with and without...

  4. Degradation by acetic acid for crystalline Si photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Masuda, Atsushi; Uchiyama, Naomi; Hara, Yukiko

    2015-04-01

    The degradation of crystalline Si photovoltaic modules during damp-heat test was studied using some test modules with and without polymer film insertion by observing electrical and electroluminescence properties and by chemical analyses. Acetic acid generated by the hydrolysis decomposition of ethylene vinyl acetate used as an encapsulant is the main origin of degradation. The change in electroluminescence images is explained on the basis of the corrosion of electrodes by acetic acid. On the other hand, little change was observed at the pn junction even after damp-heat test for a long time. Therefore, carrier generation occurs even after degradation; however, such generated carriers cannot be collected owing to corrosion of electrodes. The guiding principle that module structure and module materials without saving acetic acid into the modules was obtained.

  5. 21 CFR 522.2477 - Trenbolone acetate and estradiol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...has not been established for this product in preruminating calves. Do not use in calves to be processed for veal. (3) Pasture cattle (slaughter, stocker, and feeder steers and heifers )—(i) Amount . (A) 40 mg trenbolone acetate and...

  6. Membrane-bound enzymes. III. Protease activity in leucocytes in relation to erythrocyte membranes.

    PubMed

    Heller, M; Edelstein, P; Mayer, M

    1975-12-16

    Protease activity was detected in membranes of human bovine erythrocytes prepared by the conventional procedures which include washing and removal of the "buffy layer". The enzyme was extracted by 0.75 M KCNS or (NH4)2SO4 and was activated by 0.4 to 0.5 M of the same salts. Colored, particulate hide powder-azure, membrane fractions and soluble proteins such as hemoglobin, casein or albumin were susceptible to hydrolysis by the membraneous protease. Partial purification of the enzyme was accomplished through disc-gel electrophoresis on polyacrylamide in the presence of 0.25% positively charged detergents like cetyltrimethylammonium bromide. An alkaline protease (pH 7.4) with properties similar to those of the erythrocyte enzyme was found in leucocytes. The similarity between the properties of the leucocytic and erythrocytic proteases and the correlation of the activity in erythrocyte membranes with content of white cells in these preparations, suggest that enzymatic activities in the contaminating leucocytes are responsible for the activity of membraneous proteases in erythrocytes. PMID:92

  7. Analysis of microsatellites by direct blotting electrophoresis and chemiluminescence detection.

    PubMed

    Mekus, F; Dörk, T; Deufel, T; Morral, N; Tümmler, B

    1995-10-01

    We describe a fast and reliable method for the nonradioactive analysis of microsatellites. For three dinucleotide repeats within the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the separation of polymerase chain reaction (PCR) products generated with biotinylated primers on a direct blotting electrophoresis system and subsequent chemiluminescence detection is shown. In direct blotting electrophoresis, the separation of DNA fragments depended linearly on size. The reproducible resolution allowed reliable assignment of allele lengths to a given signal. The nonradioactive detection protocol was advantageous compared to radioactive methods: samples could be analyzed within one day due to the fast signal development by 3-(4-methoxyspiro[1,2-dioxetane-3,2'-(5'- chloro)tricyclo[3.3.1.1.3,7]decan]-4-yl)phenylphosphate disodium salt (CSPD). Variation of exposure times enabled differentiation between major bands and byproducts of comparable intensity that are due to the slippage of the Taq polymerase during PCR amplification. PMID:8586058

  8. SDS capillary gel electrophoresis of proteins in microfabricated channels

    PubMed Central

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

    1999-01-01

    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

  9. Microchip Electrophoresis at Elevated Temperatures and High Separation Field Strengths

    PubMed Central

    Mitra, Indranil; Marczak, Steven P.; Jacobson, Stephen C.

    2014-01-01

    We report free-solution microchip electrophoresis performed at elevated temperatures and high separation field strengths. We used microfluidic devices with 11-cm long separation channels to conduct separations at temperatures between 22 (ambient) and 45 °C and field strengths from 100 to 1000 V/cm. To evaluate separation performance, N-glycans were used as a model system and labeled with 8-aminopyrene-1,3,6-trisulfonic acid to impart charge for electrophoresis and render them fluorescent. Typically, increased diffusivity at higher temperatures leads to increased axial dispersion and poor separation performance; however, we demonstrate that sufficiently high separation field strengths can be used to offset the impact of increased diffusivity in order to maintain separation efficiency. Efficiencies for these free-solution separations are the same at temperatures of 25, 35, and 45 °C with separation field strengths ?500 V/cm. PMID:24114979

  10. Electrophoresis of a DNA Coil Near a Nanopore

    E-print Network

    Rowghanian, Payam

    2013-01-01

    Motivated by DNA electrophoresis near a nanopore, we consider the flow field around an "elongated jet", a long thin source which injects momentum into a liquid. This solution qualitatively describes the electro-osmotic flow around a long rigid polymer, where due to electrohydrodynamic coupling, the solvent receives momentum from the electric field. Based on the qualitative behavior of the elongated jet solution, we develop a coarse-grained scheme which reproduces the known theoretical results regarding the electrophoretic behavior of a long rigid polymer and a polymer coil in a uniform field, which we then exploit to analyze the electrophoresis of a polymer coil in the non-uniform field near a nanopore.

  11. Electrophoresis of a DNA Coil Near a Nanopore

    E-print Network

    Payam Rowghanian; Alexander Y. Grosberg

    2013-06-19

    Motivated by DNA electrophoresis near a nanopore, we consider the flow field around an "elongated jet", a long thin source which injects momentum into a liquid. This solution qualitatively describes the electro-osmotic flow around a long rigid polymer, where due to electrohydrodynamic coupling, the solvent receives momentum from the electric field. Based on the qualitative behavior of the elongated jet solution, we develop a coarse-grained scheme which reproduces the known theoretical results regarding the electrophoretic behavior of a long rigid polymer and a polymer coil in a uniform field, which we then exploit to analyze the electrophoresis of a polymer coil in the non-uniform field near a nanopore.

  12. Imaging Catalytic Surfaces by Multiplexed Capillary Electrophoresis With Absorption Detection

    SciTech Connect

    Michael Christodoulou

    2002-08-27

    A new technique for in situ imaging and screening heterogeneous catalysts by using multiplexed capillary electrophoresis with absorption detection was developed. By bundling the inlets of a large number of capillaries, an imaging probe can be created that can be used to sample products formed directly from a catalytic surface with high spatial resolution. In this work, they used surfaces made of platinum, iron or gold wires as model catalytic surfaces for imaging. Various shapes were recorded including squares and triangles. Model catalytic surfaces consisting of both iron and platinum wires in the shape of a cross were also imaged successfully. Each of the two wires produced a different electrochemical product that was separated by capillary electrophoresis. Based on the collected data they were able to distinguish the products from each wire in the reconstructed image.

  13. Effects of coating rectangular microscopic electrophoresis chamber with methylcellulose

    NASA Technical Reports Server (NTRS)

    Plank, L. D.

    1985-01-01

    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.

  14. Magnetic Membrane System

    DOEpatents

    McElfresh, Michael W.; (Livermore, CA); Lucas, Matthew S.; (Pasadena, CA)

    2004-12-30

    The present invention provides a membrane with magnetic particles. In one embodiment the membrane is created by mixing particles in a non-magnetic base. The membrane may act as an actuator, a sensor, a pump, a valve, or other device. A magnet is operatively connected to the membrane. The magnet acts on and changes the shape of the membrane.

  15. Disposition of eslicarbazepine acetate in the mouse after oral administration.

    PubMed

    Alves, Gilberto; Figueiredo, Isabel; Castel-Branco, Margarida; Lourenço, Nulita; Falcão, Amílcar; Caramona, Margarida; Soares-da-Silva, Patrício

    2008-10-01

    Eslicarbazepine acetate is a promising antiepileptic drug structurally related to carbamazepine and oxcarbazepine, which is in the final phase of clinical development. The metabolism of eslicarbazepine acetate is clearly species dependent and, in this case, among small laboratory animals, the mouse seems to be the most relevant species to humans. Hence, the aim of this study was to investigate the plasma, brain and liver disposition of eslicarbazepine acetate in mice to better understand its disposition in humans. Adult male CD-1 mice were treated orally with a single dose of eslicarbazepine acetate 350 mg/kg. Blood samples, brain and liver tissues were taken at 0.25, 0.5, 0.75, 1, 2, 4, 6, 10, 16 and 24 h post-dose. Plasma and tissue levels of eslicarbazepine acetate and its metabolites (S-licarbazepine, R-licarbazepine and oxcarbazepine) were assessed by using high-performance liquid chromatography-ultraviolet detection. Both eslicarbazepine acetate and R-licarbazepine concentrations were below the limit of quantification of the assay in all matrices. Eslicarbazepine acetate was rapidly and extensively metabolized to S-licarbazepine (major metabolite), which was oxidized to oxcarbazepine to a small extent. The brain/plasma ratios suggest that the brain exposure to S-licarbazepine and oxcarbazepine was approximately 30% of their total systemic exposure. However, S-licarbazepine crossed the blood-brain barrier (BBB) less efficiently than oxcarbazepine. On the other hand, the liver/plasma ratios support the notion that S-licarbazepine undergoes hepatic accumulation, whereas oxcarbazepine appears to leave this compartment twice as fast as S-licarbazepine. Thus, the diffusion through the BBB is favourable to oxcarbazepine and the liver acts like a deposit of the pharmacologically active metabolite of eslicarbazepine acetate (S-licarbazepine). PMID:18710399

  16. Intrinsic hydration of monopositive uranyl hydroxide, nitrate, and acetate cations

    Microsoft Academic Search

    Winnie Chien; Victor Anbalagan; Melvin Zandler; Michael Van Stipdonk; Dorothy Hanna; Garold Gresham; Gary Groenewold

    2004-01-01

    The intrinsic hydration of three monopositive uranyl-anion complexes (UO2A)+ (where A = acetate, nitrate, or hydroxide) was investigated using ion-trap mass spectrometry (IT-MS). The relative rates\\u000a for the formation of the monohydrates [(UO2A)(H2O)]+, with respect to the anion, followed the trend: Acetate ? nitrate ? hydroxide. This finding was rationalized in terms of\\u000a the donation of electron density by the

  17. Purification of Acetic Acid Wastewater using Layer Melt Crystallization

    Microsoft Academic Search

    Kwang-Joo Kim

    2008-01-01

    Ice crystalline layers were prepared from a binary eutectic mixture of acetic acid and water using layer melt crystallization. The crystalline layers were obtained under the conditions of the cooling temperature at 269, 268, and 267 K, the feed compositions of 0.5, 1.0, and 5.0 wt% acetic acid, and the cooling rates of 0.1, 0.5, and 1.0 K\\/min. After crystallization, sweating operations were

  18. Quantification of protein complexes by blue native electrophoresis.

    PubMed

    Heidler, Juliana; Strecker, Valentina; Csintalan, Florian; Bleier, Lea; Wittig, Ilka

    2013-01-01

    Blue native electrophoresis (BNE) is a long established method for the analysis of native protein complexes. Applications of BNE range from investigating subunit composition, stoichiometry, and assembly of single protein complexes to profiling of whole complexomes. BNE is an indispensible tool to diagnostically analyze cells and tissues from patients with mitochondrial disorders or model organisms. Since functional proteomic studies often require quantification of protein complexes, we describe here different quantification methods subsequent to protein complex separation by BNE. PMID:23996189

  19. DNA walks one step at a time in electrophoresis

    Microsoft Academic Search

    Juan Guan; Bo Wang; Steve Granick

    2011-01-01

    Testing the classical view that in DNA gel electrophoresis, long polymer chains navigate through their gel environment via reptation, we reach a different conclusion: this driven motion proceeds by stick-slip. Our single-molecule experiments visualize fluorescent-labeled lambda-DNA, whose intramolecular conformations are resolved with 30 ms resolution using home-written software. Combining hundreds to thousands of trajectories under amplitudes of electric field ranging

  20. High current-density electrodes suitable for laser doppler electrophoresis

    Microsoft Academic Search

    E. E. Uzgiris

    1980-01-01

    The principal electrode problems associated with laser Doppler electrophoresis in high salt conditions and at high current densities (pH drift, colloidal particle ejection, and gas bubbling) have been solved through the use of hybrid electrodes that are platinized Ag\\/AgCl or by the use of platinized Ag. For salt conditions well below physiological saline an agarose gel overcoating on either of