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Sample records for capillaries critical glycerol

  1. Critical Velocity in Open Capillary Channel Flows

    NASA Technical Reports Server (NTRS)

    Rosendahl, Uwe; Dreyer, Michael E.; Rath, Hans J.; Motil, Brian; Singh, Bhim S. (Technical Monitor)

    2001-01-01

    We investigate forced liquid flows through open capillary channels with free surfaces experimentally. The experiments were performed under low gravity conditions in the Bremen Drop Tower and on board the sounding rocket TEXUS-37. Open capillary channels (vanes) are used in surface tension tanks to transport the propellant and to provide a flow path for the bubble-free liquid supply to the thrusters. Since the free surfaces can only withstand a certain pressure differential between the liquid and ambient, the flow rate in the channel is limited. The maximum flow rate is achieved when the surfaces collapse and gas is ingested into the outlet. Since experimental and theoretical data of this flow rate limitation is lacking, the safety factors for the application of vanes in surface tension tanks must be unnecessary high. The aim of the investigation is to determine the maximum liquid flow rate and the corresponding critical flow velocity. The characteristic nondimensional parameters, OHNESORGE number, and gap ratio, cover a wide range of usual vanes. For the theoretical approach a one-dimensional momentum balance was set up. The numerical solution yields the maximum volume flux and the position of the free surface in good agreement with the experiments.

  2. Critical Velocities in Open Capillary Flow

    NASA Technical Reports Server (NTRS)

    Dreyer, Michael; Langbein, Dieter; Rath, Hans J.

    1996-01-01

    This paper describes the proposed research program on open capillary flow and the preliminary work performed theoretically and in drop tower experiments. The work focuses on the fundamental physical understanding of the flow through capillary bound geometries, where the circumference of the cross section of the flow path contains free surfaces. Examples for such a flow configuration are capillary vanes in surface tension tanks, flow along edges and corners and flow through liquid bridges. The geometries may be classified by their cross section areas, wetted circumferences and the radii of curvature of the free surfaces. In the streaming float zone the flow path is bound by a free surface only. The ribbon vane is a model for vane types used in surface tension tanks, where a structure in proximity to the tank wall forms a capillary gap. A groove is used in heat pipes for the transportation of the condensed working fluid to the heat source and a wedge may occur in a spaceborne experiment where fluid has to be transported by the means of surface tension. The research objectives are the determination of the maximum volume flux, the observation of the free surfaces and the liquid flow inside the flow path as well as the evaluation of the limiting capillary wave speed. The restriction of the maximum volume flux is due to convective forces (flow velocity exceeding the capillary wave speed) and/or viscous forces, i.e. the viscous head loss along the flow path must be compensated by the capillary pressure due to the curved free surface. Exceeding the maximum volume flux leads to the choking of the flow path, thus the free surface collapses and.gas ingestion occurs at the outlet. The means are ground-based experimental work with plateau tanks and in a drop tower, a sounding rocket flight, and theoretical analysis with integral balances as well as full three dimensional CFD solutions for flow with free surfaces.

  3. The use of capillary electrophoresis with contactless conductivity detection for monitoring of glycerol in adipose tissues during a sporting performance.

    PubMed

    Tůma, Petr; Málková, Klára; Wedellová, Zuzana; Samcová, Eva; Stulík, Karel

    2010-06-01

    A CE procedure employing capacitively coupled contactless conductivity detection has been developed for direct determination of the glycerol and mannitol polyalcohols in biological and pharmacological samples. Both glycerol and mannitol are fully separated from the sample matrix within very short times of 3.0 and 3.9 min, respectively, when using the optimized BGE, 60 mM H3BO3+30 mM LiOH (pH 9.1). The LODs amount to 0.5 microM for glycerol and 0.3 microM for mannitol. The repeatability of the glycerol determination in real biological materials is characterized by the coefficient of variation values, 0.5 and 3.2%, for the migration time and the peak area, respectively. The procedure has been used to monitor the free glycerol concentration in adipose tissue microdialyzates. A physiological study has demonstrated that the lipolysis occurring during a sporting action can be stimulated by local application of adrenaline. The procedure has further been utilized to determine mannitol in a pharmacological preparation. PMID:20564696

  4. Enhanced critical heat flux by capillary driven liquid flow on the well-designed surface

    NASA Astrophysics Data System (ADS)

    Kim, Dong Eok; Park, Su Cheong; Yu, Dong In; Kim, Moo Hwan; Ahn, Ho Seon

    2015-07-01

    Based on the unique design of the surface morphology, we investigated the effects of gravity and capillary pressure on Critical heat flux (CHF). The micro-structured surfaces for pool boiling tests were comprised with both the rectangular cavity and microchannel structures. The microcavity structures could intrinsically block the liquid flow by capillary pressure effect, and the capillary flow into the boiling surface was one-dimensionally induced only through the microchannel region. Thus, we could clearly establish the relationship between the CHF and capillary wicking flow. The driving potentials for the liquid inflow can be classified into the hydrostatic head by gravitational force, and the capillary pressure induced by the interactions of vapor bubbles, liquid film, and surface solid structures. Through the analysis of the experimental data and visualization of vapor bubble behaviors, we present that the liquid supplement to maintain the nucleate boiling regime in pool boiling condition is governed by the gravitational pressure head and capillary pressure effect.

  5. Electropolishing the bore of metal capillary tubes: A technique for adjusting the critical flow.

    PubMed

    Stoffels, J J; Ells, D R

    1979-12-01

    A technique has been developed for electropolishing the bore of metal capillary tubes. Although developed specifically for stainless-steel tubes, the technique should be directly applicable to other metals. Tubes with inside diameter as small as 0.20 mm and 110 mm long have been successfully electropolished. The electropolishing technique can be used to increase the critical flow of a capillary tube in a controllable way. PMID:18699437

  6. Glycerol-3-phosphate is a critical mobile inducer of systemic immunity in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol-3-phosphate (G3P) is an important metabolite that contributes to the growth and disease-related physiologies of prokaryotes, plants, animals and humans alike. Here we show that G3P serves as the inducer of an important form of broad-spectrum immunity in plants, termed systemic acquired resi...

  7. Critical energy barrier for capillary condensation in mesopores: Hysteresis and reversibility

    NASA Astrophysics Data System (ADS)

    Hiratsuka, Tatsumasa; Tanaka, Hideki; Miyahara, Minoru T.

    2016-04-01

    Capillary condensation in the regime of developing hysteresis occurs at a vapor pressure, Pcond, that is less than that of the vapor-like spinodal. This is because the energy barrier for the vapor-liquid transition from a metastable state at Pcond becomes equal to the energy fluctuation of the system; however, a detailed mechanism of the spontaneous transition has not been acquired even through extensive experimental and simulation studies. We therefore construct accurate atomistic silica mesopore models for MCM-41 and perform molecular simulations (gauge cell Monte Carlo and grand canonical Monte Carlo) for argon adsorption on the models at subcritical temperatures. A careful comparison between the simulation and experiment reveals that the energy barrier for the capillary condensation has a critical dimensionless value, Wc* = 0.175, which corresponds to the thermal fluctuation of the system and depends neither on the mesopore size nor on the temperature. We show that the critical energy barrier Wc* controls the capillary condensation pressure Pcond and also determines a boundary between the reversible condensation/evaporation regime and the developing hysteresis regime.

  8. Critical energy barrier for capillary condensation in mesopores: Hysteresis and reversibility.

    PubMed

    Hiratsuka, Tatsumasa; Tanaka, Hideki; Miyahara, Minoru T

    2016-04-28

    Capillary condensation in the regime of developing hysteresis occurs at a vapor pressure, Pcond, that is less than that of the vapor-like spinodal. This is because the energy barrier for the vapor-liquid transition from a metastable state at Pcond becomes equal to the energy fluctuation of the system; however, a detailed mechanism of the spontaneous transition has not been acquired even through extensive experimental and simulation studies. We therefore construct accurate atomistic silica mesopore models for MCM-41 and perform molecular simulations (gauge cell Monte Carlo and grand canonical Monte Carlo) for argon adsorption on the models at subcritical temperatures. A careful comparison between the simulation and experiment reveals that the energy barrier for the capillary condensation has a critical dimensionless value, Wc (*) = 0.175, which corresponds to the thermal fluctuation of the system and depends neither on the mesopore size nor on the temperature. We show that the critical energy barrier Wc (*) controls the capillary condensation pressure Pcond and also determines a boundary between the reversible condensation/evaporation regime and the developing hysteresis regime. PMID:27131561

  9. Collective motion of macroscopic spheres floating on capillary ripples: dynamic heterogeneity and dynamic criticality.

    PubMed

    Sanlı, Ceyda; Saitoh, Kuniyasu; Luding, Stefan; van der Meer, Devaraj

    2014-09-01

    When a densely packed monolayer of macroscopic spheres floats on chaotic capillary Faraday waves, a coexistence of large scale convective motion and caging dynamics typical for glassy systems is observed. We subtract the convective mean flow using a coarse graining (homogenization) method and reveal subdiffusion for the caging time scales followed by a diffusive regime at later times. We apply the methods developed to study dynamic heterogeneity and show that the typical time and length scales of the fluctuations due to rearrangements of observed particle groups significantly increase when the system approaches its largest experimentally accessible packing concentration. To connect the system to the dynamic criticality literature, we fit power laws to our results. The resultant critical exponents are consistent with those found in densely packed suspensions of colloids. PMID:25314540

  10. Online Capillary IsoElectric Focusing-ElectroSpray Ionization Mass Spectrometry (CIEF-ESI MS) in Glycerol-Water Media for the Separation and Characterization of Hydrophilic and Hydrophobic Proteins.

    PubMed

    Mokaddem, Meriem; d'Orlyé, Fanny; Varenne, Anne

    2016-01-01

    Capillary isoelectric focusing (CIEF) is a high-resolution technique for the separation of ampholytes, such as proteins, according to their isoelectric point. CIEF coupled online with MS is regarded as a promising alternative to 2-D PAGE for fast proteome analysis with high-resolving capabilities and enhanced structural information without the drawbacks of conventional slab-gel electrophoresis. However, online coupling has been rarely described, as it presents some difficulties. A new methodology for the online coupling of CIEF with electrospray ionization mass spectrometry (ESI-MS) has been developed in glycerol-water media. This new integrated methodology provides a mean for the characterization of a large number of hydrophilic and hydrophobic proteins. PMID:27473481

  11. MR measurement of critical phase transition dynamics and supercritical fluid dynamics in capillary and porous media flow.

    PubMed

    Rassi, Erik M; Codd, Sarah L; Seymour, Joseph D

    2012-01-01

    Supercritical fluids (SCF) are useful solvents in green chemistry and oil recovery and are of great current interest in the context of carbon sequestration. Magnetic resonance techniques were applied to study near critical and supercritical dynamics for pump driven flow through a capillary and a packed bed porous media. Velocity maps and displacement propagators measure the dynamics of C(2)F(6) at pressures below, at, and above the critical pressure and at temperatures below and above the critical temperature. Displacement propagators were measured at various displacement observation times to quantify the time evolution of dynamics. In capillary flow, the critical phase transition fluid C(2)F(6) showed increased compressibility compared to the near critical gas and supercritical fluid. These flows exhibit large variations in buoyancy arising from large changes in density due to very small changes in temperature. PMID:22018694

  12. A critical overview of non-aqueous capillary electrophoresis. Part I: mobility and separation selectivity.

    PubMed

    Kenndler, Ernst

    2014-03-28

    This two-part review critically gives an overview on the theoretical and practical advances in non-aqueous capillary electrophoresis (NACE) achieved over the recent five years. Part I starts out by reviewing the aspects relevant to electromigration in organic solvents and evaluates potential advantages of the latter in comparison to aqueous solvent systems. The crucial role of solubility for the species involved in CE - analytes and back ground electrolyte constituents - is discussed both for ionic and neutral compounds. The impact of organic solvents on the electrophoretic and electroosmotic mobility and on the ionization (pKa values) of weak acids and bases is highlighted. Special emphasis is placed on methanol, acetonitrile and mixtures of these solvents, being the most frequent employed media for NACE applications. In addition, also solvents less commonly used in NACE will be covered, including other alcohols, amides (formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide), propylene carbonate, dimethylsulphoxide, and nitromethane. The discussions address the consequences of dramatic pKa shifts frequently seen for weak acids and bases, and the important contributions of medium-specific electroosmotic flow (EOF) to electromigration in nonaqueous media. Important for NACE, the role of the water content on pKa and mobility is analyzed. Finally, association phenomena rather specific to nonaqueous solvents (ion pairing, homo- and heteroconjugation) will be addressed, along with their potential advantages for the development of NACE separation protocols. It is pointed out that this review is not intended as a listing of all papers that have been published on NACE in the period mentioned above. It rather deals with general aspects of migration and selectivity in organic solvent systems, and discusses - critically - examples from the literature with particular interest to the topic. An analog discussion about the role of the solvent on efficiency

  13. Measurements of the capillary trapping of super-critical carbon dioxide in Berea sandstone

    NASA Astrophysics Data System (ADS)

    Pentland, Christopher H.; El-Maghraby, Rehab; Iglauer, Stefan; Blunt, Martin J.

    2011-03-01

    We measure primary drainage capillary pressure and the relationship between initial and residual non-wetting phase saturation for a supercritical carbon dioxide (CO2)-brine system in Berea sandstone. We use the semi-permeable disk (porous-plate) coreflood method. Brine and CO2 were equilibrated prior to injection to ensure immiscible displacement. A maximum CO2 saturation of 85% was measured for an applied capillary pressure of 296 kPa. After injection of brine the CO2 saturation dropped to 35%; this is less than the maximum trapped saturation of 48% measured in an equivalent n-decane (oil)-brine experiment. The dimensionless capillary pressure is the same to within experimental error for supercritical CO2-brine, n-decane-brine and a mercury-air system. CO2 is the non-wetting phase and significant quantities can be trapped by capillary forces. We discuss the implications for CO2 storage.

  14. Critical effect of pore characteristics on capillary infiltration in mesoporous films.

    PubMed

    Ceratti, D R; Faustini, M; Sinturel, C; Vayer, M; Dahirel, V; Jardat, M; Grosso, D

    2015-03-12

    Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (<50 nm in diameter), the presence of bottle necks considerably slows down the infiltration rate. At such a small dimension, evaporation/capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer. PMID:25723817

  15. Critical effect of pore characteristics on capillary infiltration in mesoporous films

    NASA Astrophysics Data System (ADS)

    Ceratti, D. R.; Faustini, M.; Sinturel, C.; Vayer, M.; Dahirel, V.; Jardat, M.; Grosso, D.

    2015-03-01

    Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (<50 nm in diameter), the presence of bottle necks considerably slows down the infiltration rate. At such a small dimension, evaporation/capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer.

  16. Separation of poly(acrylic acid) salts according to topology using capillary electrophoresis in the critical conditions.

    PubMed

    Maniego, Alison R; Ang, Dale; Guillaneuf, Yohann; Lefay, Catherine; Gigmes, Didier; Aldrich-Wright, Janice R; Gaborieau, Marianne; Castignolles, Patrice

    2013-11-01

    Branching was detected in polyacrylates synthesised through radical polymerization via solution-state NMR, while inconsistencies have been reported for the determination of the molar mass of hydrophilic polyacrylates using aqueous-phase and organic-phase size-exclusion chromatography. In this work, poly(sodium acrylate)s, PNaAs, of various topologies were separated for the first time using free-solution capillary electrophoresis (CE). Free-solution CE does not separate the PNaAs by their molar mass, similarly to separations by liquid chromatography in the critical conditions, rather by different topologies (linear, star branched, and hyperbranched). The electrophoretic mobility of PNaAs increases as the degree of branching decreases. Separation is shown to be not only by the topology but also by the end groups as expected for a separation in the critical conditions: replacing a relatively bulky nitroxide end group with hydrogen atom yielded a higher electrophoretic mobility. This novel method, capillary electrophoresis in the critical conditions enabled, for the first time, the separation of hydrophilic polyacrylates according to their topology (branching) and their chain ends. This will allow meaningful and accurate characterization of their branched topologies as well as molar masses and progress in for advanced applications such as drug delivery or flocculation. PMID:23732867

  17. Pore-scale modeling of Capillary Penetration of Wetting Liquid into 3D Fibrous Media: A Critical Examination of Equivalent Capillary Concept

    NASA Astrophysics Data System (ADS)

    Palakurthi, Nikhil Kumar; Ghia, Urmila; Comer, Ken

    2013-11-01

    Capillary penetration of liquid through fibrous porous media is important in many applications such as printing, drug delivery patches, sanitary wipes, and performance fabrics. Historically, capillary transport (with a distinct liquid propagating front) in porous media is modeled using capillary-bundle theory. However, it is not clear if the capillary model (Washburn equation) describes the fluid transport in porous media accurately, as it assumes uniformity of pore sizes in the porous medium. The present work investigates the limitations of the applicability of the capillary model by studying liquid penetration through virtual fibrous media with uniform and non-uniform pore-sizes. For the non-uniform-pore fibrous medium, the effective capillary radius of the fibrous medium was estimated from the pore-size distribution curve. Liquid penetration into the 3D virtual fibrous medium at micro-scale was simulated using OpenFOAM, and the numerical results were compared with the Washburn-equation capillary-model predictions. Preliminary results show that the Washburn equation over-predicts the height rise in the early stages (purely inertial and visco-inertial stages) of capillary transport.

  18. Preservation of peritubular capillary endothelial integrity and increasing pericytes may be critical to recovery from postischemic acute kidney injury

    PubMed Central

    Kwon, Osun; Hong, Seok-Min; Sutton, Timothy A.; Temm, Constance J.

    2008-01-01

    Decreased renal blood flow following an ischemic insult contributes to a reduction in glomerular filtration. However, little is known about the underlying cellular or subcellular mechanisms mediating reduced renal blood flow in human ischemic acute kidney injury (AKI) or acute renal failure (ARF). To examine renal vascular injury following ischemia, intraoperative graft biopsies were performed after reperfusion in 21 cadaveric renal allografts. Confocal fluorescence microscopy was utilized to examine vascular smooth muscle and endothelial cell integrity as well as peritubular interstitial pericytes in the biopsies. The reperfused, transplanted kidneys exhibited postischemic injury to the renal vasculature, as demonstrated by disorganization/disarray of the actin cytoskeleton in vascular smooth muscle cells and disappearance of von Willebrand factor from vascular endothelial cells. Damage to peritubular capillary endothelial cells was more severe in subjects destined to have sustained ARF than in those with rapid recovery of their graft function. In addition, peritubular pericytes/myofibroblasts were more pronounced in recipients destined to recover than those with sustained ARF. Taken together, these data suggest damage to the renal vasculature occurs after ischemia-reperfusion in human kidneys. Preservation of peritubular capillary endothelial integrity and increasing pericytes may be critical to recovery from postischemic AKI. PMID:18562634

  19. Phase separation in a binary mixture confined between symmetric parallel plates: Capillary condensation transition near the bulk critical point

    NASA Astrophysics Data System (ADS)

    Yabunaka, Shunsuke; Okamoto, Ryuichi; Onuki, Akira

    2013-03-01

    We investigate phase separation of near-critical binary mixtures between parallel symmetric walls in the strong adsorption regime. We take into account the renormalization effect due to the critical fluctuations using the recent local functional theory [Okamoto and Onuki, J. Chem. Phys.0021-960610.1063/1.3693331 136, 114704 (2012)]. In statics, a van der Waals loop is obtained in the relation between the average order parameter <ψ> in the film and the chemical potential when the temperature T is lower than the film critical temperature Tcca (in the case of an upper critical solution temperature). In dynamics, we lower T below the capillary condensation line from above Tcca. We calculate the subsequent time development assuming no mass exchange between the film and the reservoir. In the early stage, the order parameter ψ changes only in the direction perpendicular to the walls. For sufficiently deep quenching, such one-dimensional profiles become unstable with respect to the fluctuations varying in the lateral directions. The late-stage coarsening is then accelerated by the hydrodynamic interaction. A pancake domain of the phase disfavored by the walls finally appears in the middle of the film.

  20. Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

    SciTech Connect

    Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

    2008-06-30

    Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

  1. Capillary Hemangioma

    MedlinePlus

    ... Why do capillary hemangiomas on the eyelids cause vision problems? Capillary Hemangiomas of the eyelid can cause ... a capillary hemangioma in the eye socket cause vision problems? A capillary hemangioma in the eye socket ( ...

  2. Capillary electrophoresis

    SciTech Connect

    Warner, M.

    1988-10-15

    Rapid instrumental methods for performing electrophoretic separations in capillary tubes have recently been developed, making capillary electrophoresis one of the most exciting new techniques available to analytical chemists. This article discusses detection methods, applications, and the future of capillary electrophoresis.

  3. Capillary sample

    MedlinePlus

    ... using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a limited amount of blood can be drawn using this method. The procedure has some risks (see below). Capillary ...

  4. Glycerol combustion and emissions

    EPA Science Inventory

    With the growing capacity in biodiesel production and the resulting glut of the glycerol by-product, there is increasing interest in finding alternative uses for crude glycerol. One option may be to burn it locally for combined process heat and power, replacing fossil fuels and i...

  5. Preparation of Glycerol Cinnamate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol was combined with cinnamic acid to prepare the corresponding ester, glycerol cinnamate. Conversions of 81% were achieved after 16 hr in toluene at reflux conditions. The product was recovered by extraction with distilled water and diethyl ether. The isolated product displayed strong abso...

  6. Hydrolysis of polycarbonate in sub-critical water in fused silica capillary reactor with in situ Raman spectroscopy

    USGS Publications Warehouse

    Pan, Z.; Chou, I.-Ming; Burruss, R.C.

    2009-01-01

    The advantages of using fused silica capillary reactor (FSCR) instead of conventional autoclave for studying chemical reactions at elevated pressure and temperature conditions were demonstrated in this study, including the allowance for visual observation under a microscope and in situ Raman spectroscopic characterization of polycarbonate and coexisting phases during hydrolysis in subcritical water. ?? 2009 The Royal Society of Chemistry.

  7. Fermentation of xylose to glycerol by Rhizopus javanicus

    SciTech Connect

    Lu, Z.; Yang, C.W.; Tsao, G.T.

    1995-12-31

    Glycerol production from xylose fermentation using Rhizopus javanicus (ATCC 22581) has been investigated in shake flasks. The medium composition (xylose concentration, nitrogen sources), aeration rate, and temperature have been found to affect the accumulation and yield of glycerol. Some of these effects are explained in terms of the critical parameters, osmotic pressure, and dissolved oxygen levels in the medium. Relatively high glycerol yields and concentrations have been obtained at high sugar concentration with high level of aeration at room temperature. The addition of polyethylene glycol or sulfite can improve the yield and accumulation of glycerol.

  8. Electrochemical valorisation of glycerol.

    PubMed

    Simões, Mário; Baranton, Stève; Coutanceau, Christophe

    2012-11-01

    The worldwide glycerol stocks are increasing; to make the biodiesel industry sustainable economically, this chemical could be used as a secondary primary raw material. Electric energy or hydrogen and added-value-chemical cogeneration becomes more and more an important research topic for increasing economical and industrial interests towards electrochemical technologies. Studies on glycerol electrooxidation for fuel or electrolysis cell applications are scarce. The valorisation of glycerol is generally performed by organic chemistry reactions forming, for example, esters, glycerol carbonates, ethers, acetals or ketals. Glycerol oxidation is made up of complex pathway reactions that can produce a large number of useful intermediates or valuable fine chemicals with presently limited market impact due to expensive production processes. Many of these chemical oxidation routes lead to significant amounts of undesired by-products, and enzymatic processes are limited. Converse to classical heterogeneous processes, electrocatalytic oxidation processes can be tuned by controlling the nature, composition and structure of the electrocatalyts as well as the electrode potential. Such control may lead to very high selectivity and activity, avoiding or limiting product separation steps. The coupling of glycerol oxidation to produce chemicals with the oxygen reduction reaction in a fuel cell or water reduction reaction in an electrolysis cell on Pt-free catalysts results either in coproduction of electrical energy or hydrogen for energy storage. PMID:23112136

  9. Glycerol-induced hyperhydration

    NASA Technical Reports Server (NTRS)

    Riedesel, Marvin L.; Lyons, Timothy P.; Mcnamara, M. Colleen

    1991-01-01

    Maintenance of euhydration is essential for maximum work performance. Environments which induce hypohydration reduce plasma volume and cardiovascular performance progressively declines as does work capacity. Hyperhydration prior to exposure to dehydrating environments appears to be a potential countermeasure to the debilitating effects of hypohydration. The extravascular fluid space, being the largest fluid compartment in the body, is the most logical space by which significant hyperhydration can be accomplished. Volume and osmotic receptors in the vascular space result in physiological responses which counteract hyperhydration. Our hypothesis is that glycerol-induced hyperhydration (GIH) can accomplish extravascular fluid expansion because of the high solubility of glycerol in lipid and aqueous media. A hypertonic solution of glycerol is rapidly absorbed from the gastrointestinal tract, results in mild increases in plasma osmolality and is distributed to 65 percent of the body mass. A large volume of water ingested within minutes after glycerol intake results in increased total body water because of the osmotic action and distribution of glycerol. The resulting expanded extravascular fluid space can act as a reservoir to maintain plasma volume during exposure to dehydrating environments. The fluid shifts associated with exposure to microgravity result in increased urine production and is another example of an environment which induces hypohydration. Our goal is to demonstrate that GIH will facilitate maintenance of euhydration and cardiovascular performance during space flight and upon return to a 1 g environment.

  10. Anaerobic digestion of glycerol and co-digestion of glycerol and pig manure.

    PubMed

    Nuchdang, Sasikarn; Phalakornkule, Chantaraporn

    2012-06-30

    The potential of glycerol obtained from transesterification of waste cooking oil as a main carbon source for biogas production was investigated. The glycerol was highly contaminated with oils and fats and was pretreated with sulfuric acid. Using a carbon source of glucose as a control, we compared biogas production from the acid-treated glycerol in a synthetic medium and the acid-treated glycerol mixed with pig manure. The anaerobic digestion of acid-treated glycerol with supplement in a synthetic medium was found to be satisfactory at organic loading rates (OLR) between 1.3, 1.6 and 2.6 g chemical oxygen demand (COD) L(-1) d(-1). The maximum methane yield of 0.32 L at Standard temperature and pressure (STP) g(-1) COD removal was achieved at an OLR of 1.6 g COD L(-1) d(-1) and the methane content was 54% on an average. At a higher organic loading rate of 5.4 g COD L(-1) d(-1), the propionic acid to acetic acid ratio was higher than the critical threshold limit for metabolic imbalance. Anaerobic digestion of acid-treated glycerol with pig manure was also investigated at the COD ratio of 80:20 (glycerol:pig manure). The anaerobic digestion of acid-treated glycerol with pig manure was found to be satisfactory at organic loading rates between 1.3, 1.7, 2.9 and 5.0 g COD L(-1) d(-1) in terms of COD reduction (>80%) and methane content of (62% on an average). However, the biogas production rate was found to significantly decrease at the highest load. The maximum methane yield of 0.24 L STP g(-1) COD removal was achieved at an OLR of 1.3 g COD L(-1) d(-1). PMID:22417895

  11. Laser-based capillary polarimeter.

    PubMed

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158

  12. Coproduction of ethanol and glycerol.

    PubMed

    Gong, C S; Du, J X; Cao, N J; Tsao, G T

    2000-01-01

    Ethanol and glycerol are both metabolic products of yeasts. There are occasions when coproduction of both is considered desirable in industrial operations. In this article, we describe the potential of integrating the two processes. A LORRE Y8 yeast culture isolated from molasses is capable of efficient glycerol production from glucose, and a yeast Culture 1400 is an excellent producer of ethanol. By controlling the process conditions, the ratio of ethanol and glycerol production can be varied. PMID:10849818

  13. Characterization of the CDP-2-Glycerol Biosynthetic Pathway in Streptococcus pneumoniae▿ †

    PubMed Central

    Wang, Quan; Xu, Yanli; Perepelov, Andrei V.; Xiong, Wei; Wei, Dongmei; Shashkov, Alexander S.; Knirel, Yuriy A.; Feng, Lu; Wang, Lei

    2010-01-01

    Capsule polysaccharide (CPS) plays an important role in the virulence of Streptococcus pneumoniae and is usually used as the pneumococcal vaccine target. Glycerol-2-phosphate is found in the CPS of S. pneumoniae types 15A and 23F and is rarely found in the polysaccharides of other bacteria. The biosynthetic pathway of the nucleotide-activated form of glycerol-2-phosphate (NDP-2-glycerol) has never been identified. In this study, three genes (gtp1, gtp2, and gtp3) from S. pneumoniae 23F that have been proposed to be involved in the synthesis of NDP-2-glycerol were cloned and the enzyme products were expressed, purified, and assayed for their respective activities. Capillary electrophoresis was used to detect novel products from the enzyme-substrate reactions, and the structure of the product was elucidated using electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. Gtp1 was identified as a reductase that catalyzes the conversion of 1,3-dihydroxyacetone to glycerol, Gtp3 was identified as a glycerol-2-phosphotransferase that catalyzes the conversion of glycerol to glycerol-2-phosphate, and Gtp2 was identified as a cytidylyltransferase that transfers CTP to glycerol-2-phosphate to form CDP-2-glycerol as the final product. The kinetic parameters of Gtp1 and Gtp2 were characterized in depth, and the effects of temperature, pH, and cations on these two enzymes were analyzed. This is the first time that the biosynthetic pathway of CDP-2-glycerol has been identified biochemically; this pathway provides a method to enzymatically synthesize this compound. PMID:20729354

  14. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde

    SciTech Connect

    Slininger, P.J.; Bothast, R.J.

    1985-12-01

    Chemical oxidation of 3-hydroxypropionaldehyde (3-HPA) leads to acrylic acid, an industrially important polymerizable monomer currently derived from petroleum. As the availability of petroleum declines, 3-HPA may become attractive as a product to be obtained through fermentation of glycerol, a renewable resource. When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32/sup 0/C, although the overall 3-HPA yield increased continuously within the 25 to 37/sup 0/C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield.

  15. Flavor impacts of glycerol in the processing of yeast fermented beverages: a review.

    PubMed

    Zhao, Xiangdong; Procopio, Susanne; Becker, Thomas

    2015-12-01

    Glycerol contributes to the beverage body and fullness. Moreover, it also influences the flavor intensity. As a major byproduct, glycerol not only serves critical roles in yeast osmoregulation and redox balancing, but also acts as the carbon competitor against ethanol in alcoholic fermentation. Therefore, increasing glycerol yield benefits both the flavor and ethanol reduction for the fermented beverages. Glycerol yield has been elevated either by fermentation optimization or by yeast genetic modification. The fermentation optimizations reached maximum 14 g/L glycerol through screening yeast strains and optimizing fermentation parameters. Meanwhile the yeast overexpressing GPD1 (encoding glycerol-3-phosphate dehydrogenase) produced up to 6 folds more glycerol for beer and wine. Except for glycerol improvement, the genetically modified yeasts accumulated dramatically undesirable compounds such as acetaldehyde, acetate and acetoin which are detrimental for beverage flavor. In comparison, the natural high glycerol producers showed strain-specific manner on the yeast-derived aroma compounds like volatile acids, fusel alcohols, esters, and aldehydes. Temperature, sugar concentration, nitrogen composition, oxygen and pH-value, which influence glycerol biosynthesis, also obtained various effects on the production of aromatic compounds. In the current review, we firstly deliberate the organoleptic contributions of glycerol for fermented beverages. Furthermore, glycerol optimization strategies are discussed regarding to the yield improvement, the genes expressions, the overall flavor impacts and the feasibilities in beverage applications. Lastly, for improving beverage flavor by glycerol optimization, a high-throughput platform is proposed to increase the screening capacity of yeast strains and parameters in the processing of fermented beverages. PMID:26604336

  16. Characterization of crude glycerol from biodiesel plants.

    PubMed

    Hu, Shengjun; Luo, Xiaolan; Wan, Caixia; Li, Yebo

    2012-06-13

    Characterization of crude glycerol is very important to its value-added conversion. In this study, the physical and chemical properties of five biodiesel-derived crude glycerol samples were determined. Three methods, including iodometric-periodic acid method, high performance liquid chromatography (HPLC), and gas chromatography (GC), were shown to be suitable for the determination of glycerol content in crude glycerol. The compositional analysis of crude glycerol was successfully achieved by crude glycerol fractionation and characterization of the obtained fractions (aqueous and organic) using titrimetric, HPLC, and GC analyses. The aqueous fraction consisted mainly of glycerol, methanol, and water, while the organic fraction contained fatty acid methyl esters (FAMEs), free fatty acids (FFAs), and glycerides. Despite the wide variations in the proportion of their components, all raw crude glycerol samples were shown to contain glycerol, soap, methanol, FAMEs, water, glycerides, FFAs, and ash. PMID:22612334

  17. Glycerol production of various strains of saccharomyces

    SciTech Connect

    Radler, F.; Schuetz, H.

    1982-01-01

    The quantity of glycerol as principal by-product of the alcoholic fermentation depends to a large extent on the yeast strain. Different strains of Saccharomyces cerevisiae were found to form amounts of glycerol varying between 4.2 to 10.4 g/L. The formation of glycerol is regarded as a result of the competition between alcohol dehydrogenase and glycerol-3-phosphate dehydrogenase that compete for the reduced coenzyme NADH/sub 2/. High and low glycerol forming yeast strains showed large differences in the activity of glycerol-3-phosphate dehydrogenase and only small variation in the activity of alcohol dehydrogenase. The total amount of glycerol formed was also influenced by amino acids. In thiamine deficient media a decrease in glycerol formation was observed. Experiments indicate a correlation between the formation of acetaldehyde and glycerol and the production of cell mass that may be of practical interest. (Refs. 12).

  18. Capillaroscopy and the measurement of capillary pressure

    PubMed Central

    Shore, Angela C

    2000-01-01

    Capillaries play a critical role in cardiovascular function as the point of exchange of nutrients and waste products between the tissues and circulation. Studies of capillary function in man are limited by access to the vascular bed. However, skin capillaries can readily be studied by the technique of capillaroscopy which enables the investigator to assess morphology, density and blood flow velocity. It is also possible to estimate capillary pressure by direct cannulation using glass micropipettes. This review will describe the techniques used to make these assessments and will outline some of the changes that are seen in health and disease. PMID:11136289

  19. Identifying plasma glycerol concentration associated with urinary glycerol excretion in trained humans.

    PubMed

    Nelson, Jeff L; Harmon, Molly E; Robergs, Robert A

    2011-11-01

    Glycerol has been used as a means to legitimately hyperhydrate the body in an attempt to offset the deleterious effects of dehydration. It has the potential to mask blood doping practices and as a result has been added to the WADA prohibited substance list. The purpose of this study was to identify the plasma glycerol concentration coinciding with urinary glycerol excretion. Twelve healthy, trained male subjects completed five separate trials under resting conditions. For each trial, subjects consumed a different glycerol dose (0.025, 0.05, 0.10, 0.15, or 0.20 g glycerol/kg LBM) of a 5% glycerol solution in order to determine at what plasma glycerol concentration an increase in urine glycerol concentration becomes apparent. Based on regression analysis, plasma glycerol concentrations > 0.327 ± 0.190 mmol/L and a glycerol dose > 0.032 ± 0.010 g glycerol/kg LBM would be associated with urinary glycerol excretion. There were significant linear relationships between peak plasma glycerol concentration and time to reach peak plasma glycerol concentration to the ingested glycerol doses. Our findings illustrate the importance of considering the effect of urinary glycerol excretion on legitimate hyperhydration regimens as well as suggesting that it is possible to detect surreptitious use of glycerol as a masking agent through urinary analysis. PMID:22080901

  20. Capillary muscle

    PubMed Central

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-01-01

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This “hyperbolic” force–velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136–195]. Hill’s heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973–976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971–973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318; Deshcherevskiĭ VI (1968) Biofizika 13(5):928–935]. Here, we develop a capillary analog of the sarcomere obeying Hill’s equation and discuss its analogy with muscles. PMID:25944938

  1. Capillary muscle.

    PubMed

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-05-19

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This "hyperbolic" force-velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136-195]. Hill's heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973-976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971-973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255-318; Deshcherevskiĭ VI (1968) Biofizika 13(5):928-935]. Here, we develop a capillary analog of the sarcomere obeying Hill's equation and discuss its analogy with muscles. PMID:25944938

  2. On the response of a water surface to a surface pressure source moving at trans-critical gravity-capillary wave speeds

    NASA Astrophysics Data System (ADS)

    Masnadi, Naeem; Cho, Yeunwoo; Duncan, James H.; Akylas, Triantaphyllos

    2015-11-01

    The non-linear response of a water free surface to a pressure source moving at speeds near the minimum speed of linear gravity-capillary waves (Cmin ~ 23 cm/s) is investigated with experiments and theory. In the experiments, waves are generated by a vertically oriented air-jet that moves at a constant speed over the water surface in a long tank. The 3-D surface shape behind the air-jet is measured using a cinematic refraction-based technique combined with an LIF technique. At towing speeds just below Cmin, an unsteady pattern is formed where localized depressions periodically appear in pairs and move away from the source along the arms of a downstream V-shaped pattern. This behavior is analogous to the periodic shedding of solitary waves upstream of a source moving at the maximum wave speed in shallow water. The gravity-capillary depressions are rapidly damped by viscosity and their speed-amplitude characteristics closely match those from inviscid calculations of gravity-capillary lumps. The shedding frequency of the lumps in the present experiments increases with both increasing towing speed and air-flow rate. Predictions of this behavior using a model equation that incorporates damping and a quadratic nonlinearity are in good agreement with the experiments. The partial support of the National Science Foundation under grant OCE0751853 is gratefully acknowledged.

  3. Glycerol inhibition of ruminal lipolysis in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of...

  4. Glycerol clearance in alcoholic liver disease.

    PubMed Central

    Johnston, D G; Alberti, K G; Wright, R; Blain, P G

    1982-01-01

    Glycerol clearance was studied by a primed dose-constant infusion technique in 14 patients with alcoholic liver disease and six normal control subjects. Fasting blood glycerol concentrations were raised in the alcoholic subjects (0.09 +/- 0.01 vs 0.06 +/- 0.01 mumol/l, p less than 0.05) and glycerol clearance was impaired (24.5 +/- 1.9 vs 37.5 +/- 3.2 ml/kg/min, p less than 0.005). Endogenous production rate of glycerol and distribution space at steady state were similar in alcoholic and control subjects. The metabolic clearance rate of glycerol correlated negatively with basal glycerol concentrations. Thus tissue uptake of glycerol is impaired in liver disease. As glycerol is metabolised primarily in the liver by conversion to glucose, these data suggest a defect of gluconeogenesis in alcoholic liver disease. PMID:7076002

  5. Antioxidant properties of feruloyl glycerol derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The natural plant components, 1-feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (F2G), were synthesized by the enzymatic esterification of glycerol and soybean oil mono- and diacylglycerols, respectively, with ethyl ferulate. The isolated FG and F2G were examined for their antioxidant acti...

  6. Kinetics of cinnamoyl glycerol formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The esterifications of glycerol with cinnamic acid, 2-methoxy cinnamic acid, and 4-methoxy cinnamic acid were investigated in batch reactions. Conversions of over 50% were achieved for cinnamic acid and 4-methoxy cinnamic acid within 8 hours. After 24 hours conversions of over 80% were obtained fo...

  7. Capillary wave measurements on helically-supported capillary channels

    NASA Astrophysics Data System (ADS)

    Chandurwala, Fahim; Thiessen, David

    2010-10-01

    NASA is considering power generation by the Rankine cycle to save weight on long-duration manned missions to the moon or Mars. Phase separation technology is critical to this process in microgravity. Arrays of capillary channels might be useful for filtering liquid drops from a flowing vapor. The efficiency of droplet capture by a helically-supported capillary channel is being studied. A droplet impinging on the channel launches capillary waves that propagate down the channel helping to dissipate some of the drop's kinetic energy. High-speed video of the channel combined with image processing allows for measurement of the amplitude and speed of the wave packets. Increasing the pitch of the support structure decreases the wave speed. An understanding of the dynamic response of the channel to drop impact is a first step in predicting drop-capture efficiency.

  8. Esterification of glycerol from biodiesel production to glycerol carbonate in non-catalytic supercritical dimethyl carbonate.

    PubMed

    Ilham, Zul; Saka, Shiro

    2016-01-01

    Conversion of glycerol from biodiesel production to glycerol carbonate was studied by esterification with dimethyl carbonate in a non-catalytic supercritical condition. It was found that in a non-catalytic supercritical condition, glycerol at higher purity gave higher yield of glycerol carbonate at 98 wt% after reaction at 300 °C/20-40 MPa/15 min. The yield of glycerol carbonate was observed to increase with molar ratio, temperature, pressure and time until a certain equilibrium limit. The existence of impurities such as water and remnants of alkaline catalyst in crude glycerol will direct the reaction to produce glycidol. Although impurities might not be desirable, the non-catalytic supercritical dimethyl carbonate could be an alternative method for conversion of glycerol from biodiesel production to value-added glycerol carbonate.Graphical abstractPlausible reaction scheme for conversion of glycerol to glycerol carbonate in non-catalytic supercritical dimethyl carbonate. PMID:27386367

  9. Mathematical modeling of glycerol biotransformation

    NASA Astrophysics Data System (ADS)

    Popova-Krumova, Petya; Yankova, Sofia; Ilieva, Biliana

    2013-12-01

    A method for mathematical modeling of glycerol biotransformation by Klebsiella oxytoca is presented. Glycerol is a renewable resource for it is formed as a by-product during biodiesel production. Because of its large volume production, it seems to be a good idea to develop a technology that converts this waste into products of high value (1, 3-Propanediol; 2, 3-Butanediol). The kinetic model of this process consists of many equations and parameters. The minimization of the least square function will be used for model parameters identification. In cases of parameters identification in multiparameter models the minimization of the least square function is very difficult because it is multiextremal. This is the main problem in the multiextremal function minimization which will be solved on the base a hierarchical approach, using a polynomial approximation of the experimental data.

  10. Experimental investigation of charged liquid jet efflux from a capillary

    NASA Astrophysics Data System (ADS)

    Zhakin, A. I.; Belov, P. A.; Kuz'ko, A. E.

    2013-03-01

    The shapes and electrical characteristics of charged liquid (water, ethanol, glycerol, castor oil) jets emitted from a metal capillary have been experimentally studied depending on the applied high voltage. A map of efflux regimes in the flow velocity-applied voltage coordinates is constructed for water. The effects of medium viscosity, surface tension, and charge relaxation time on the laws of jet efflux are analyzed.

  11. Selective glycerol oxidation by electrocatalytic dehydrogenation.

    PubMed

    Kim, Hyung Ju; Lee, Jechan; Green, Sara K; Huber, George W; Kim, Won Bae

    2014-04-01

    This study demonstrates that an electrochemical dehydrogenation process can be used to oxidize glycerol to glyceraldehyde and glyceric acid even without using stoichiometric chemical oxidants. A glyceric acid selectivity of 87.0 % at 91.8 % glycerol conversion was obtained in an electrocatalytic batch reactor. A continuous-flow electrocatalytic reactor had over an 80 % high glyceric acid selectivity at 10 % glycerol conversion, as well as greater reaction rates than either an electrocatalytic or a conventional catalytic batch reactor. PMID:24664518

  12. Glycerol-3-phosphatase of Corynebacterium glutamicum.

    PubMed

    Lindner, Steffen N; Meiswinkel, Tobias M; Panhorst, Maren; Youn, Jung-Won; Wiefel, Lars; Wendisch, Volker F

    2012-06-15

    Formation of glycerol as by-product of amino acid production by Corynebacterium glutamicum has been observed under certain conditions, but the enzyme(s) involved in its synthesis from glycerol-3-phosphate were not known. It was shown here that cg1700 encodes an enzyme active as a glycerol-3-phosphatase (GPP) hydrolyzing glycerol-3-phosphate to inorganic phosphate and glycerol. GPP was found to be active as a homodimer. The enzyme preferred conditions of neutral pH and requires Mg²⁺ or Mn²⁺ for its activity. GPP dephosphorylated both L- and D-glycerol-3-phosphate with a preference for the D-enantiomer. The maximal activity of GPP was estimated to be 31.1 and 1.7 U mg⁻¹ with K(M) values of 3.8 and 2.9 mM for DL- and L-glycerol-3-phosphate, respectively. For physiological analysis a gpp deletion mutant was constructed and shown to lack the ability to produce detectable glycerol concentrations. Vice versa, gpp overexpression increased glycerol accumulation during growth in fructose minimal medium. It has been demonstrated previously that intracellular accumulation of glycerol-3-phosphate is growth inhibitory as shown for a recombinant C. glutamicum strain overproducing glycerokinase and glycerol facilitator genes from E. coli in media containing glycerol. In this strain, overexpression of gpp restored growth in the presence of glycerol as intracellular glycerol-3-phosphate concentrations were reduced to wild-type levels. In C. glutamicum wild type, GPP was shown to be involved in utilization of DL-glycerol-3-phosphate as source of phosphorus, since growth with DL-glycerol-3-phosphate as sole phosphorus source was reduced in the gpp deletion strain whereas it was accelerated upon gpp overexpression. As GPP homologues were found to be encoded in the genomes of many other bacteria, the gpp homologues of Escherichia coli (b2293) and Bacillus subtilis (BSU09240, BSU34970) as well as gpp1 from the plant Arabidosis thaliana were overexpressed in E. coli MG1655 and

  13. Glycerol inhibition of ruminal lipolysis in vitro.

    PubMed

    Edwards, H D; Anderson, R C; Miller, R K; Taylor, T M; Hardin, M D; Smith, S B; Krueger, N A; Nisbet, D J

    2012-09-01

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of supplemental glycerol on rumen lipolysis, mixed populations of ruminal bacteria were incubated with 6 or 20% glycerol (vol/vol). After 48-h anaerobic incubation of mixed culture rumen fluid, rates of free fatty acid production (nmol/mL per h) for the 6 and 20% glycerol-supplemented samples were decreased by 80 and 86%, respectively, compared with rates from nonsupplemented control cultures (12.4±1.0; mean ± SE). Conversely, assay of the prominent ruminal lipase-producing bacteria Anaerovibrio lipolyticus 5S, Butyrivibrio fibrisolvens 49, and Propionibacterium species avidum and acnes revealed no effect of 2 or 10% (vol/vol) added glycerol on lipolytic activity by these organisms. Supplementing glycerol at 6% on a vol/vol basis, equivalent to supplementing glycerol at approximately 8 to 15% of diet dry matter, effectively reduced lipolysis. However, the mechanism of glycerol inhibition of ruminal lipolysis remains to be demonstrated. PMID:22916923

  14. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions.

    PubMed

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-14

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on. PMID:27421414

  15. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-01

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on.

  16. Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

    NASA Astrophysics Data System (ADS)

    Blyth, Alison J.; Schouten, Stefan

    2013-05-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples from 16 different sites around the globe, and test whether proxies based on isoprenoid tetraethers (TEX86) or branched tetraethers (MBT/CBT) are correlated with measured surface and cave mean annual air temperature (MAT). The results show that the TEX86 has a strong relationship with measured temperature (r2 = 0.78, standard error of the estimate 2.3 °C, when calibrated with surface MAT). Furthermore, the MBT/CBT also showed a significant relationship with temperature (r2 = 0.73, standard error of the estimate 2.7 °C, when calibrated with surface MAT). Some issues remain requiring future work, in particular the development of a larger calibration sample set with measured cave temperature data, and the investigation of controls other than temperature on GDGT distribution, but overall the results indicate that GDGT based proxies derived from speleothems may be highly viable new methods for reconstructing continental palaeotemperatures.

  17. On the Role of the Blood Vessel Endothelial Microvilli in the Blood Flow in Small Capillaries

    PubMed Central

    Makarov, Vladimir; Zueva, Lidia; Sanabria, Priscila; Wessinger, William Dave; Golubeva, Tatiana; Khmelinskii, Igor; Inyushin, Mikhail

    2015-01-01

    Endothelial microvilli that protrude into the capillary lumen, although invisible in the optical microscopy, may play an important role in the blood flow control in the capillaries. Because of the plug effects, the width of the gap between the capillary wall and the blood cell is especially critical for the blood flow dynamics in capillaries, while microvilli located on the capillary wall can easily control the velocity of the blood flow. We report that microvilli in the capillaries of different vertebrate species have similar characteristics and density, suggesting similarities between the respective regulation mechanisms. A simplified physical model of the capillary effective diameter control by the microvilli is presented. PMID:26604921

  18. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1995-01-01

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibres to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands.

  19. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1995-08-08

    A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

  20. Sterility Testing by Capillary Electrophoresis: A Comparison of On-line Preconcentration Approaches in Capillaries with Greater Internal Diameters

    PubMed Central

    Petr, Jan; Jiang, Chunxia; Sevcik, Juraj; Tesarova, Eva; Armstrong, Daniel W.

    2015-01-01

    Detection of microbial contamination is of critical importance in the medical and the food industry. Rapid tests for the absence or presence of viable microorganisms are in urgent demand. Capillary electrophoresis is a modern analytical technique that can be adapted for rapid screening of microbial contamination. However, the small dimensions of capillaries allow introduction of only a small fraction of the sample, which can be problematic when examining large samples. In this article, we examine the possibilities of introducing larger sample volumes using capillaries with greater internal diameters (i.d.) together with different stacking techniques. The use of 0.32 mm i.d. capillary and the injection of 60 % of the capillary volume led to approximately 120-fold improvement of the injected sample volume over the classical injection 5% of a 0.10 mm i.d. capillary. The setup we described opens new possibilities in sterility testing using capillary electrophoresis. PMID:19847804

  1. RUMINAL FERMENTATION OF PROPYLENE GLYCOL AND GLYCEROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in dec...

  2. Glycerol citrate polyesters produced through microwave heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of various heating methods without catalysis to prepare copolyesters from citric acid:glycerol blends were studied. In the presence of short term microwave treatments, i.e., 60 sec at 1200 W, blends of glycerol and citric acid invariably formed solid amorphous copolyesters. Fourier tra...

  3. Thermal and physical characterization of glycerol polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol polyesters were prepared by the condensation of glycerol and adipic acid, azelaic acid, sebacic acid, or suberic acids. After 48 hours at 125 deg C the polymers were clear and flexible. Samples of the reaction mixtures were analyzed by modulated differential scanning calorimetry to identi...

  4. Correlation spectroscopy applied to glycerol polyester spectra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent development of glycerol polyesters for use as controlled release matrix materials in the nutraceuticals and pharmaceuticals industries presented a unique opportunity to apply correlation spectroscopy. In a typical formulation the glycerol is reacted with a polyfunctional acid such as citr...

  5. Formulation and Applications of Glycerol Polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased production of biodiesel in the U.S. and Europe during the past several years has created an oversupply of glycerol, creating lower domestic profitability. In addition, increased petroleum prices have driven up the cost of synthetic polymers made from petrochemicals. Glycerol can be polym...

  6. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  7. Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

    PubMed

    Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

    2010-11-01

    Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate. PMID:20502921

  8. Capillary Flow Limitations of Nanowicks

    NASA Astrophysics Data System (ADS)

    Zhang, Conan; Hidrovo, Carlos

    2009-11-01

    Thermal management is an important issue in microelectronic systems. The inaccessibility and diminishing size of these systems, however, requires that the heat management components be reliable and compact, such as is the case with heat pipes. In most intermediate temperature heat pipes typically found in microelectronics, the critical heat flux is governed by the capillary limit. Given the projected increases in computer chip heat fluxes, it is important to investigate the use of nanowicks as a means of raising this capillary limit. A theoretical model was developed to simulate flow through a vertical nanopillar array by balancing the capillary driving forces and the viscous losses in a quasi-steady state dynamic formulation. Based on this model, the maximum mass flow and its critical heat flux can be found for a wick given its microstructure geometry. These values were also found experimentally for commercially available wicks and nanowicks. We found that nanowicks provide lower mass flow rates than conventional wicks, mainly due to a reduced cross section. However, nanowicks achieved higher velocities and show promise over some conventional heat pipe wicks.

  9. Capillary-scale polarimetry for flowing streams.

    PubMed

    Swinney, K; Nodorft, J; Bornhop, D J

    2001-05-01

    A micro-polarimeter with a 40 nL probe volume was configured so that it is compatible with capillary-scale flowing stream analysis. The optical configuration consists of two polarizing optics, a capillary, a laser source and a photodetector which is very simple to configure with low cost components. This unique polarimeter is based upon the interaction of a linearly polarized laser beam and a capillary tube, in this case one with an inner diameter of 250 microns. Side illumination of the tube results in a 360 degrees fan of scattered light, which contains a set of interference fringes that change in response to optically active solutes. Solutes that exhibit optical activity are quantifiable and are detected by analyzing the polarization state of the backscattered light. The ability of the instrument to make extremely sensitive optical activity measurements in flowing streams is shown by the determination of (R)-mandelic acid, with a detection limit of 66 x 10(-6) M (507 x 10(-12) g), and the non-optically active control, glycerol. Additionally, the detector was configured to minimize refractive index perturbations. PMID:11394312

  10. Characterising Microstructured Materials Using a Capillary Rheometer

    NASA Astrophysics Data System (ADS)

    Hicks, Christopher I.; See, Howard; Arabo, Emad Y. M.

    2008-07-01

    A parallel plate and capillary rheometer have been used to rheologically characterize an Australian hard wheat flour-water dough over an extensive range of shear rates (10-3-104 s-1). Torsional measurements showed that the shear viscosity of dough increased with strain to a maximum value then decreased, suggesting a breakdown of the dough structure. This was consistent with other published data on doughs. Capillary experiments revealed the shear thinning behavior of dough, which was described by a power-law model. The wall slip behavior of dough was examined, revealing a critical shear stress at which slip occurs for a 1 mm diameter capillary. The capillary data was best linked to the torsional data at low strain values (˜0.1) as expected given the nature of sampling in the two rheometers.

  11. Aquaporin-10 Represents an Alternative Pathway for Glycerol Efflux from Human Adipocytes

    PubMed Central

    Laforenza, Umberto; Scaffino, Manuela F.; Gastaldi, Giulia

    2013-01-01

    Background Glycerol outflow from adipocytes has been considered for a decade to be mediated by aquaporin-7, an aquaglyceroporin highly expressed in the adipose tissue. Its involvement in glycerol metabolism has been widely studied also in humans. Recent studies in different aquaporin-7 KO mice models pose two different questions 1) the exact localization of aquaporin-7 in human white adipose tissue; 2) the existence of other aquaglyceroporins that work with aquaporin-7 to guarantee glycerol efflux and thus a normal adiposity in humans. To this purpose we investigated the expression, the localization and the functioning of aquaglyceroporin-10 in subcutaneous white adipose tissue, in isolated and cultured differentiated adipocytes. Methodology/Principal Findings Aquaporin-7 and -10 were expressed in the white adipose tissue both at mRNA and at protein level. Immunofluorescence revealed aquaporin-7 and -10 labelling in the human adipose tissue both to the plasma membrane and to a thin rim of cytoplasm of adipocytes. Aquaporin-7, but not aquaporin-10, colocalized with the endothelial marker CD34. Human cultured differentiated adipocytes showed an aquaporin-7 and -10 labelling mainly in the cytoplasm and in the lipid droplets with insulin reinforcing the lipid droplets staining and isoproterenol inducing its translocation to the plasma membrane compartment. Water and glycerol permeability measurements using adipocytes and adipose membrane vesicles confirmed the presence of functioning aquaglyceroporins. Aquaporin-10 silencing in human differentiated adipocytes resulted in a 50% decrease of glycerol and osmotic water permeability. Conclusions/Significance The results indicate that aquaporin-7, differently from mice, is present in both adipocyte and capillary plasma membranes of human adipose tissue. Aquaporin-10, on the contrary, is expressed exclusively in the adipocytes. The expression of two aquaglyceroporins in human adipose tissue is particularly important for the

  12. TEACHING PHYSICS: Capillary effects

    NASA Astrophysics Data System (ADS)

    Ivanov, Dragia; Petrova, Hristina

    2000-07-01

    We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

  13. The role of chemisorbed hydroxyl species in alkaline electrocatalysis of glycerol on gold.

    PubMed

    Shi, X; Simpson, D E; Roy, D

    2015-05-01

    The mechanism of energy conversion in a direct glycerol fuel cell (DGFC) is governed by the anode supported heterogeneous steps of glycerol electro-oxidation. In aerated alkaline electrolytes, glycerol also participates in a base catalyzed process, which can release certain species mixing with the anode catalyzed surface products. As a result, selective probing of the surface catalytic reactions involving such systems can be difficult. The present work addresses this issue for a gold anode by using the analytical capability of cyclic voltammetry (CV). In addition, surface plasmon resonance measurements are used to optically probe the adsorption characteristics of the electrolyte species. The net exchange current of the oxidation process and the transfer coefficient of the rate determining step are evaluated by analyzing the CV data. The interfacial reactions and their products on Au are identified by measuring the number of electrons released during the electro-oxidation of glycerol. The results indicate that these reactions are facilitated by the surface bound hydroxyl species on Au (chemisorbed OH(-) and faradaically formed Au-OH). By comparing the findings for stationary and rotating electrodes, it is shown that, convective mass transport is critical to maintaining efficient progression of the consecutive oxidation steps of glycerol. In the absence of hydrodynamic support, the main surface products of glycerol oxidation appear to be glyceraldehyde, glycerate and malonate, formed through a net six-electron route. In the presence of controlled convection, a ten-electron process is activated, where mesaxolate is the likely additional product. PMID:25855265

  14. Production of biohydrogen from crude glycerol in an upflow column bioreactor.

    PubMed

    Dounavis, Athanasios S; Ntaikou, Ioanna; Lyberatos, Gerasimos

    2015-12-01

    A continuous attached growth process for the production of biohydrogen from crude glycerol was developed. The process consisted of an anaerobic up-flow column bioreactor (UFCB), packed with cylindrical ceramic beads, which constituted the support matrix for the attachment of bacterial cells. The effect of crude glycerol concentration, pH and hydraulic retention time on glycerol conversion, hydrogen yield and metabolite distribution was investigated. It was shown that the most critical parameter for the efficient bioconversion was the pH of the influent, whereas the hydrogen yield increased with an increase in feed glycerol concentration and a decrease in the hydraulic retention time. The main soluble metabolite detected was 1,3-propanediol in all cases, followed by butyric and hexanoic acids. The latter is reported to be produced from glycerol for the first time. Acidification of the waste reached 38.5%, and the maximum H2 productivity was 107.3 ± 0.7 L/kg waste glycerol at optimal conditions. PMID:26441027

  15. Capillary rheometry for thermosets

    NASA Technical Reports Server (NTRS)

    Malguarnera, S. C.; Carroll, D. R.

    1982-01-01

    Capillary rheometry is effectively used with thermosets. Most important is providing a uniform temperature in the barrel. This was successfully accomplished by using a circulating hot oil system. Standard capillary rheometry methods provide the dependence of thermoset apparent viscosity on shear rate, temperature and time. Such information is very useful in evaluating resin processability and in setting preliminary fabrication conditions.

  16. Ethanolysis of rapeseed oil - distribution of ethyl esters, glycerides and glycerol between ester and glycerol phases.

    PubMed

    Cernoch, Michal; Hájek, Martin; Skopal, Frantisek

    2010-04-01

    The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides, and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters, and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined. PMID:20005094

  17. Efficient green methanol synthesis from glycerol

    NASA Astrophysics Data System (ADS)

    Haider, Muhammad H.; Dummer, Nicholas F.; Knight, David W.; Jenkins, Robert L.; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H.; Hutchings, Graham J.

    2015-12-01

    The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.

  18. Production of 3-Hydroxypropionaldehyde from Glycerol

    PubMed Central

    Slininger, Patricia J.; Bothast, Rodney J.; Smiley, Karl L.

    1983-01-01

    3-Hydroxypropionaldehyde is a precursor to acrolein, which can be used as an intermediate for making acrylic acid and a variety of other useful industrial chemicals. Conversion of glycerol, a renewable resource, to 3-hydroxypropionaldehyde was attempted via action of glycerol dehydrase isolated from Lactobacillus sp. strain NRRL B-1720. This method, however, was unsatisfactory because enzyme activity was lost within 60 to 90 min after the reaction initiation. Fermentation of glycerol by whole cells of Klebsiella pneumoniae NRRL B-199 in the presence of optimal semicarbazide hydrochloride proved more effective. Using this technique, glycerol solutions of 30 g/liter yielded 3-hydroxypropionaldehyde solutions of 13.1 g/liter. Thus, a conversion efficiency equal to 55% of the theoretical maximum was realized. PMID:16346353

  19. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1998-04-21

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

  20. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1996-12-10

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

  1. 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.

  2. 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.

  3. Glycerol monooleate-blood interactions.

    PubMed

    Ericsson, Emma M; Faxälv, Lars; Weissenrieder, Anna; Askendal, Agneta; Lindahl, Tomas L; Tengvall, Pentti

    2009-01-01

    In the present study the initial blood compatibility of glycerol monooleate (GMO)-coated surfaces was evaluated after deposition to surfaces and in bulk. The model surface was silica onto which multiple layers of fibrinogen or human serum albumin (HSA) was immobilized. The protein-coated surfaces were subsequently dip-coated in GMO in ethanol and used for blood plasma and whole blood experiments. The characterization methods included null ellipsometry, scanning electron microscopy, imaging of coagulation, hemolysis test and whole blood coagulation time by free oscillation rheometry. The results showed a GMO film thickness of approximately 350 A (approximately 4 microg/cm(2)) upon dip-coating in ethanolic solution. A major part of the deposited layer detached in aqueous solutions, especially during shear conditions. The coagulation time on GMO was significantly prolonged compared to that on HSA coated silica. Whole blood tests showed that GMO is a very weak hemolytic agent. Deposited GMO detached easily from surfaces upon rinsing or shearing, although a stable layer with undefined phase structure and a thickness of 50-70 A remained on HSA and fibrinogen precoated surfaces. This indicates that GMO has stronger adhesive forces to its substrate compared to the cohesive forces acting within the bulk GMO. The ability of GMO to detach from itself and tentatively form micelles or lipid bilayers when subjected to flowing blood may be of use in extravascular applications. It is concluded that GMO results in weak blood activation, and the material may in spite of this be suitable in selected biomaterial applications, especially as a biosealant and in colloidal dispersions. PMID:18996684

  4. Synthesis of Glycerol Carbonate by Transesterification of Glycerol with Urea Over Zn/Al Mixed Oxide.

    PubMed

    Ryu, Young Bok; Baek, Jae Ho; Kim, Yangdo; Lee, Man Sig

    2015-01-01

    Reactions of glycerol carbonate using glycerol and urea have been carried out previously using ZnSO4 and ZnO catalysts, and high yields have been reported using ZnSO4 as catalyst. However, this salt is soluble in glycerol, and recycling of catalyst is difficult after the reaction. In this study, we prepared a mixed metal oxide catalyst using Zn and Al, and this catalyst consisted of a mixture of ZnO and ZnAl2O4. We confirmed the conversion of glycerol and the yield of glycerol carbonate of the amount of Al. As a result, we obtained a yield of 82.3% and a conversion of 82.7%. In addition we obtained high yield in recycling of catalyst. The yield of the glycerol carbonate increases with an increase of acid and base site of catalysts and the highest catalytic activity was obtained when acid/base ratio was approx. 1. From this result, we may conclude that the acid and base site density and ratio of catalysts were very important parameters in the synthesis of glycerol carbonate from urea and glycerol. PMID:26328352

  5. Radiometric assays for glycerol, glucose, and glycogen.

    PubMed

    Bradley, D C; Kaslow, H R

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus (1971, J. Biol. Chem. 246, 3885-3894) for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays. PMID:2817333

  6. Radiometric assays for glycerol, glucose, and glycogen

    SciTech Connect

    Bradley, D.C.; Kaslow, H.R. )

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.

  7. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1984-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  8. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    1982-01-01

    An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

  9. Capillary saturation and desaturation

    NASA Astrophysics Data System (ADS)

    Hilfer, R.; Armstrong, R. T.; Berg, S.; Georgiadis, A.; Ott, H.

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment.

  10. Catalytic glycerol steam reforming for hydrogen production

    NASA Astrophysics Data System (ADS)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  11. Catalytic glycerol steam reforming for hydrogen production

    SciTech Connect

    Dan, Monica Mihet, Maria Lazar, Mihaela D.

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  12. Facilitating protein crystal cryoprotection in thick-walled plastic capillaries by high-pressure cryocooling

    PubMed Central

    Chen, Yi-Fan; Tate, Mark W.; Gruner, Sol M.

    2009-01-01

    Many steps in the X-ray crystallographic solution of protein structures have been automated. However, the harvesting and cryocooling of crystals still rely primarily on manual handling, frequently with consequent mechanical damage. An attractive alternative is to grow crystals directly inside robust plastic capillaries that may be cryocooled and mounted on the beamline goniometer. In this case, it is still desirable to devise a way to cryoprotect the crystals, which is difficult owing to the poor thermal conductivity of thick plastic capillary walls and the large thermal mass of the capillary and internal mother liquor. A method is described to circumvent these difficulties. It is shown that high-pressure cryocooling substantially reduced the minimal concentrations of cryoprotectants required to cryocool water inside capillaries without formation of ice crystals. The minimal concentrations of PEG 200, PEG 400 and glycerol necessary for complete vitrification under pressure cryocooling were determined. PMID:19529790

  13. L-lactate production from biodiesel-derived crude glycerol by metabolically engineered Enterococcus faecalis: cytotoxic evaluation of biodiesel waste and development of a glycerol-inducible gene expression system.

    PubMed

    Doi, Yuki

    2015-03-01

    Biodiesel waste is a by-product of the biodiesel production process that contains a large amount of crude glycerol. To reuse the crude glycerol, a novel bioconversion process using Enterococcus faecalis was developed through physiological studies. The E. faecalis strain W11 could use biodiesel waste as a carbon source, although cell growth was significantly inhibited by the oil component in the biodiesel waste, which decreased the cellular NADH/NAD(+) ratio and then induced oxidative stress to cells. When W11 was cultured with glycerol, the maximum culture density (optical density at 600 nm [OD600]) under anaerobic conditions was decreased 8-fold by the oil component compared with that under aerobic conditions. Furthermore, W11 cultured with dihydroxyacetone (DHA) could show slight or no growth in the presence of the oil component with or without oxygen. These results indicated that the DHA kinase reaction in the glycerol metabolic pathway was sensitive to the oil component as an oxidant. The lactate dehydrogenase (Ldh) activity of W11 during anaerobic glycerol metabolism was 4.1-fold lower than that during aerobic glycerol metabolism, which was one of the causes of low l-lactate productivity. The E. faecalis pflB gene disruptant (Δpfl mutant) expressing the ldhL1LP gene produced 300 mM l-lactate from glycerol/crude glycerol with a yield of >99% within 48 h and reached a maximum productivity of 18 mM h(-1) (1.6 g liter(-1) h(-1)). Thus, our study demonstrates that metabolically engineered E. faecalis can convert crude glycerol to l-lactate at high conversion efficiency and provides critical information on the recycling process for biodiesel waste. PMID:25576618

  14. l-Lactate Production from Biodiesel-Derived Crude Glycerol by Metabolically Engineered Enterococcus faecalis: Cytotoxic Evaluation of Biodiesel Waste and Development of a Glycerol-Inducible Gene Expression System

    PubMed Central

    2015-01-01

    Biodiesel waste is a by-product of the biodiesel production process that contains a large amount of crude glycerol. To reuse the crude glycerol, a novel bioconversion process using Enterococcus faecalis was developed through physiological studies. The E. faecalis strain W11 could use biodiesel waste as a carbon source, although cell growth was significantly inhibited by the oil component in the biodiesel waste, which decreased the cellular NADH/NAD+ ratio and then induced oxidative stress to cells. When W11 was cultured with glycerol, the maximum culture density (optical density at 600 nm [OD600]) under anaerobic conditions was decreased 8-fold by the oil component compared with that under aerobic conditions. Furthermore, W11 cultured with dihydroxyacetone (DHA) could show slight or no growth in the presence of the oil component with or without oxygen. These results indicated that the DHA kinase reaction in the glycerol metabolic pathway was sensitive to the oil component as an oxidant. The lactate dehydrogenase (Ldh) activity of W11 during anaerobic glycerol metabolism was 4.1-fold lower than that during aerobic glycerol metabolism, which was one of the causes of low l-lactate productivity. The E. faecalis pflB gene disruptant (Δpfl mutant) expressing the ldhL1LP gene produced 300 mM l-lactate from glycerol/crude glycerol with a yield of >99% within 48 h and reached a maximum productivity of 18 mM h−1 (1.6 g liter−1 h−1). Thus, our study demonstrates that metabolically engineered E. faecalis can convert crude glycerol to l-lactate at high conversion efficiency and provides critical information on the recycling process for biodiesel waste. PMID:25576618

  15. Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes

    PubMed Central

    2012-01-01

    The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC. In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production. PMID:22455837

  16. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

    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

  17. Biorefinery for Glycerol Rich Biodiesel Industry Waste.

    PubMed

    Kalia, Vipin Chandra; Prakash, Jyotsana; Koul, Shikha

    2016-06-01

    The biodiesel industry has the potential to meet the fuel requirements in the future. A few inherent lacunae of this bioprocess are the effluent, which is 10 % of the actual product, and the fact that it is 85 % glycerol along with a few impurities. Biological treatments of wastes have been known as a dependable and economical direction of overseeing them and bring some value added products as well. A novel eco-biotechnological strategy employs metabolically diverse bacteria, which ensures higher reproducibility and economics. In this article, we have opined, which organisms and what bioproducts should be the focus, while exploiting glycerol as feed. PMID:27570302

  18. Tandem transformation of glycerol to esters.

    PubMed

    Sotenko, Maria V; Rebroš, Martin; Sans, Victor S; Loponov, Konstantin N; Davidson, Matthew G; Stephens, Gill; Lapkin, Alexei A

    2012-12-31

    Tandem transformation of glycerol via microbial fermentation and enzymatic esterification is presented. The reaction can be performed with purified waste glycerol from biodiesel production in a continuous mode, combining continuous fermentation with membrane-supported enzymatic esterification. Continuous anaerobic fermentation was optimized resulting in the productivity of 2.4 g L⁻¹ h⁻¹ of 1,3-propanediol. Biphasic esterification of 1,3-propanediol was optimized to achieve ester yield of up to 75%. A hollow fibre membrane contactor with immobilized Rhizomucor miehei lipase was demonstrated for the continuous tandem fermentation-esterification process. PMID:22796408

  19. Brain capillaries in Alzheimer's disease.

    PubMed

    Baloyannis, Stavros J

    2015-01-01

    Alzheimer's disease is the most common cause of irreversible dementia, affecting mostly the presenile and senile age, shaping a tragic profile in the epilogue of the life of the suffering people. Due to the severity and the social impact of the disease an ongoing research activity is in climax nowadays, associated with many legal, social, ethical, humanitarian, philosophical and economic considerations. From the neuropathological point of view the disease is characterized by dendritic pathology, loss of synapses and dendritic spines, affecting mostly selective neuronal networks of critical importance for memory and cognition, such as the basal forebrain cholinergic system, the medial temporal regions, the hippocampus and many neocortical association areas. Tau pathology consisted of intracellular accumulation of neurofibrillary tangles of hyperphosphorilated tau protein and accumulation of Aβ-peptide's deposits, defined as neuritic plaques, are the principal neuropathological diagnostic criteria of the disease. The neurotoxic properties of the oligomerics of the Aβ-peptide and tau mediated neurodegeneration are among the main causative factors of impaired synaptic plasticity, neuronal loss, dendritic alterations and tremendous synaptic loss. The gradual degeneration of the organelles, particularly mitochondria, smooth endoplasmic reticulum and Golgi apparatus, visualized clearly by electron microscopy (EM), emphasize the importance of the oxidative stress and amyloid toxicity in the pathogenetic cascade of the disease. The vascular factor may be an important component of the whole spectrum of the pathogenesis of AD. It is of substantial importance the concept that the structural alterations of the brain capillaries, may contribute in the pathology of AD, given that the disruption of the BBB may induce exacerbation of AD pathology, by promoting inflammation around the blood capillaries and in the neuropile space diffusely. From the morphological point of view

  20. The role of aldehyde/alcohol dehydrogenase (AdhE) in ethanol production from glycerol by Klebsiella pneumoniae.

    PubMed

    Oh, Baek-Rock; Hong, Won-Kyung; Heo, Sun-Yeon; Joe, Min-ho; Seo, Jeong-Woo; Kim, Chul Ho

    2013-02-01

    Transcriptome analysis of a K. pneumoniae GEM167 mutant strain derived by irradiation with gamma rays, which exhibited high-level production of ethanol from glycerol, showed that the mutant expressed AdhE at a high level. Ethanol production decreased significantly, from 8.8 to 0.5 g l(-1), when an adhE-deficient derivative of that strain was grown on glycerol. Bacterial growth was also reduced under such conditions, showing that AdhE plays a critical role in maintenance of redox balance by catalyzing ethanol production. Overexpression of AdhE enhanced ethanol production, from pure or crude glycerol, to a maximal level of 31.9 g l(-1) under fed-batch fermentation conditions; this is the highest level of ethanol production from glycerol reported to date. PMID:23296976

  1. Effects of intravenous infusion of glycerol on blood parameters and urinary glycerol concentrations.

    PubMed

    Okano, Masato; Nishitani, Yasunori; Dohi, Michiko; Kageyama, Shinji

    2016-05-01

    In sports, the oral intake and intravenous administration of glycerol as a potential masking agent have been prohibited. The effect of glycerol on blood parameters was investigated by comparing the intravenous administration of glycerol (20g/200mL) with that of an electrolyte (8g glucose/200mL) as a comparator (n=7, fixed-dose-rate i.v. infusion, 200mL in 1h). This study was also designed to evaluate whether the urinary concentrations reached the positivity threshold after the intravenous infusion of glycerol. Significant decreases of the haemoglobin (HGB, g/dL), haematocrit (HCT, %) and OFF-h Score (OFF-score) values were observed after the infusion of glycerol (P<0.05 at 1-6h). The differences in the HGB, HCT and OFF-score between pre- and post-administration were -0.49±0.23g/dL (2h), -1.54±0.73% (2h) and -3.89±3.66 (2h), respectively. Glycerol infusion significantly increased the plasma volume by 12.1% (1h), 6.3% (2h) and 5.7% (3h) compared with the initial values. The infusion of the comparator also increased the plasma volume by 9.6% (1h), 5.8% (2h) and 4.9% (3h) compared with the values before infusion. There were no significant differences in the change of the plasma volume between the intravenous infusions of glycerol and the glucose-based electrolyte (as the comparator) (P≥0.05). This finding might indicate that glycerol itself only exhibited limited effects on the expansion of plasma. After administration of glycerol, the urinary glycerol concentrations increased from 0.0013±0.0004mg/mL to 6.86±2.86mg/mL at 1h and 6.45±3.08mg/mL at 2h. The intravenous infusion of glycerol can most likely be detected using the current urine analysis; however, the dependence of the concentration of urinary glycerol on the urine volume should be considered. PMID:26986972

  2. A macrothermodynamic approach to the limit of reversible capillary condensation.

    PubMed

    Trens, Philippe; Tanchoux, Nathalie; Galarneau, Anne; Brunel, Daniel; Fubini, Bice; Garrone, Edoardo; Fajula, François; Di Renzo, Francesco

    2005-08-30

    The threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The nonhysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butyl alcohol in MCM-41 silica confirm a 20% increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justifies the disappearing of the hysteresis loop. PMID:16114972

  3. Genetic construction of recombinant Pseudomonas chlororaphis for improved glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study is to improve by genetic engineering the glycerol metabolic capability of Pseudomonas chlororaphis which is capable of producing commercially valuable biodegradable poly(hydroxyalkanoate) (PHA) and biosurfactant rhamnolipids (RLs). In the study, glycerol uptake facilitat...

  4. Sorption behavior of mixtures of glycerol and starch.

    PubMed

    Enrione, Javier I; Hill, Sandra E; Mitchell, John R

    2007-04-18

    Glycerol is often added to starches to plasticize the product, but the presence of glycerol may also affect the water content of the samples. To evaluate the effect of glycerol on the sorption properties of starches, waxy maize, rice, and wheat starch were thermomechanically extruded in the presence of glycerol. Sorption isotherms of these extruded samples were ascertained using dynamic vapor sorption (DVS). BET and GAB modeling showed a monolayer (mo) significantly higher for waxy maize than for rice and wheat. Glycerol inclusion changed the model values, indicating reduction in sorption energy at the monolayer and restructuring of the multilayer. An interaction factor (xi) based on weight fraction models was calculated. Differences in xi were obtained when glycerol was added, varying from approximately 0.9 for 5% glycerol to approximately 0.8 for 20% glycerol, supporting the hypothesis of interactions between starch and this polyol. PMID:17362027

  5. Effect of surfactant on kinetics of thinning of capillary bridges

    NASA Astrophysics Data System (ADS)

    Nowak, Emilia; Kovalchuk, Nina; Simmons, Mark

    2015-11-01

    Kinetics of thinning of capillary bridges is of great scientific and industrial interest being of vital importance for example in various emulsification and microfluidic processes. It is well known that the rate of bridge thinning is proportional to the interfacial tension. Therefore it is expected that the process should slow down by addition of surfactant. The kinetics of capillary bridges in the presence of surfactant was studied by the dripping of liquid from a capillary tip under conditions of nearly zero flow rate (We << 1). The tested liquids were aqueous solutions of sodium lauryl ether sulphate (SLES), which is broadly used in personal care products. The viscosity, surfactant activity and adsorption kinetics have been controlled by addition of glycerol and sodium chloride. The study has shown that the kinetics of capillary bridges are determined by dynamic surface tension rather than by its equilibrium value. In particular, the kinetics of the bridge thinning for the 0.1 g L-1 aqueous SLES solution is practically the same as that of pure water despite twice lower equilibrium surface tension. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  6. Capillary condenser/evaporator

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A. (Inventor)

    2010-01-01

    A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

  7. Determining Atmospheric Pressure with a Eudiometer and Glycerol

    ERIC Educational Resources Information Center

    Brody, Jed; Rohald, Kate; Sutton, Atasha

    2010-01-01

    We consider a volume of air trapped over a glycerol column in a eudiometer. We demonstrate that there is an approximately linear relationship between the volume of trapped air and the height of the glycerol column. Simply by moving the eudiometer up and down, we cause the glycerol-column height and trapped-air volume to vary. The plot of volume…

  8. Digestable and Metabolizable Energy of Crude Glycerol in Growing Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent DE and ME value of crude glycerol for growing pigs was determined in a series of 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility with soybean oil used as the initial feedstock (AG Processing Inc., Sergeant Bluff, IA). Dietary treatments were 0, ...

  9. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  10. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  11. 1,2-Isopropylidene glycerol carbonate: preparation, characterization, and hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonate compounds based on glycerol, such as...

  12. Conversion of glycerol to hydrogen rich gas.

    PubMed

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas. PMID:24043264

  13. Glycerol oxidation using gold-containing catalysts.

    PubMed

    Villa, Alberto; Dimitratos, Nikolaos; Chan-Thaw, Carine E; Hammond, Ceri; Prati, Laura; Hutchings, Graham J

    2015-05-19

    Glycerol is an important byproduct of biodiesel production, and it is produced in significant amounts by transesterification of triglycerides with methanol. Due to the highly functionalized nature of glycerol, it is an important biochemical that can be utilized as a platform chemical for the production of high-added-value products. At present, research groups in academia and industry are exploring potential direct processes for the synthesis of useful potential chemicals using catalytic processes. Over the last 10 years, there has been huge development of potential catalytic processes using glycerol as the platform chemical. One of the most common processes investigated so far is the catalytic oxidation of glycerol at mild conditions for the formation of valuable oxygenated compounds used in the chemical and pharmaceutical industry. The major challenges associated with the selective oxidation of glycerol are (i) the control of selectivity to the desired products, (ii) high activity and resistance to poisoning, and (iii) minimizing the usage of alkaline conditions. To address these challenges, the most common catalysts used for the oxidation of glycerol are based on supported metal nanoparticles. The first significant breakthrough was the successful utilization of supported gold nanoparticles for improving the selectivity to specific products, and the second was the utilization of supported bimetallic nanoparticles based on gold, palladium, and platinum for improving activity and controlling the selectivity to the desired products. Moreover, the utilization of base-free reaction conditions for the catalytic oxidation of glycerol has unlocked new pathways for the production of free-base products, which facilitates potential industrial application. The advantages of using gold-based catalysts are the improvement of the catalyst lifetime, stability, and reusability, which are key factors for potential commercialization. In this Account, we discuss the advantages of the

  14. Synthesis of glycerol carbonate from glycerol and urea with gold-based catalysts.

    PubMed

    Hammond, Ceri; Lopez-Sanchez, Jose A; Ab Rahim, Mohd Hasbi; Dimitratos, Nikolaos; Jenkins, Robert L; Carley, Albert F; He, Qian; Kiely, Christopher J; Knight, David W; Hutchings, Graham J

    2011-04-21

    The reaction of glycerol with urea to form glycerol carbonate is mostly reported in the patent literature and to date there have been very few fundamental studies of the reaction mechanism. Furthermore, most previous studies have involved homogeneous catalysts whereas the identification of heterogeneous catalysts for this reaction would be highly beneficial. This is a very attractive reaction that utilises two inexpensive and readily available raw materials in a chemical cycle that overall, results in the chemical fixation of CO(2). This reaction also provides a route to up-grade waste glycerol produced in large quantities during the production of biodiesel. Previous reports are largely based on the utilisation of high concentrations of metal sulfates or oxides, which suffer from low intrinsic activity and selectivity. We have identified heterogeneous catalysts based on gallium, zinc, and gold supported on a range of oxides and the zeolite ZSM-5, which facilitate this reaction. The addition of each component to ZSM-5 leads to an increase in the reaction yield towards glycerol carbonate, but supported gold catalysts display the highest activity. For gold-based catalysts, MgO is the support of choice. Catalysts have been characterised by XRD, TEM, STEM and XPS, and the reaction has been studied with time-on-line analysis of products via a combination of FT-IR spectroscopy, HPLC, (13)C NMR and GC-MS analysis to evaluate the reaction pathway. Our proposed mechanism suggests that glycerol carbonate forms via the cyclization of a 2,3-dihydroxypropyl carbamate and that a subsequent reaction of glycerol carbonate with urea yields the carbamate of glycerol carbonate. Stability and reactivity studies indicate that consecutive reactions of glycerol carbonate can limit the selectivity achieved and reaction conditions can be selected to avoid this. The effect of the catalyst in the proposed mechanism is discussed. PMID:21258674

  15. The Capillary Fluidics of Espresso

    NASA Astrophysics Data System (ADS)

    Ott, Nathan; Wollman, Drew; Graf, John; Weislogel, Mark

    2014-11-01

    Espresso is enjoyed by tens of millions of people daily. The coffee is distinguished by a complex low density colloid of emulsified oils. Due to gravity, these oils rise to the surface forming a foam lid called the crema. In this work we present a variety of large length scale capillary fluidic effects for espresso in a gravity-free environment. Drop tower tests are performed to establish brief microgravity conditions under which spontaneous capillarity-driven behavior is observed. Because the variety of espresso drinks is extensive, specific property measurements are made to assess the effects of wetting and surface tension for `Italian' espresso, caffe latte, and caffe Americano. To some, the texture and aromatics of the crema play a critical role in the overall espresso experience. We show how in the low-g environment this may not be possible. We also suggest alternate methods for enjoying espresso aboard spacecraft. NASA NNX09AP66A, Glenn Research Center.

  16. Antioxidant behavior of 1-feruloyl-sn-glycerol and 1,3-diferuloyl-sn-glycerol in phospholipid liposomes 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1-Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (DFG) are two natural plant compounds that may be useful in cosmeceutical, food, and skin care applications because of excellent antioxidant properties. FG and DFG enzymatically synthesized through esterification of glycerol and soybean oil...

  17. Yeast Fps1 glycerol facilitator functions as a homotetramer.

    PubMed

    Beese-Sims, Sara E; Lee, Jongmin; Levin, David E

    2011-12-01

    The Saccharomyces cerevisiae Fps1 glycerol channel is a member of the major intrinsic protein (MIP) family of plasma membrane channel proteins that functions in osmoregulatory pathways to transport glycerol passively out of the cell. The MIP family is subdivided into members that are selectively permeable to water (aquaporins) and those permeated by glycerol (aquaglyceroporins or glycerol facilitators). Although aquaporins function as homo-tetramers with each monomer possessing its own channel, previous studies have suggested that aquaglyceroporins may function as monomers. Here we provide both genetic and biochemical evidence that Fps1 functions as a homotetramer to regulate glycerol transport in yeast. PMID:22030956

  18. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

  19. Capillary Isoelectric Focusing

    NASA Astrophysics Data System (ADS)

    Markuszewski, Michał J.; Bujak, Renata; Daghir, Emilia

    Capillary isoelectric focusing (CIEF) is a widespread technique for the analysis of peptides and proteins in biological samples. CIEF is used to separate mixtures of compounds on the basis of differences in their isoelectric point. Aspects of sample preparation, capillary selection, zone mobilization procedures as well as various detection modes used have been described and discussed. Moreover CIEF, coupled to various types of detection techniques (MALDI or LIF), has increasingly been applied to the analysis of variety different high-molecular compounds. CIEF is considered as a highly specific analytical method which may be routinely used in the separation of rare hemoglobin variants. In addition, the application of CIEF in proteomic field have been discussed on the examples of analyses of glycoproteins and immunoglobins due to the meaning in clinical diagnostic.

  20. Semipreparative capillary electrochromatography.

    PubMed

    Chen, J R; Zare, R N; Peters, E C; Svec, F; Frechét, J J

    2001-05-01

    Capillaries with inner diameters of 550 microm have successfully been packed with 1.5-microm octadecyl silica particles using frits made of macroporous polymers by the UV photopolymerization of a solution of glycidyl methacrylate and trimethylolpropane trimethacrylate. This type of frit is found superior to one made of low-melting point poly(styrene-co-divinylbenzene) beads. Bubble formation is not observed to occur within these capillary columns under our experimental conditions. Separations can be achieved with sample injection volumes as high as 1 microL. To demonstrate its semipreparative use, a mixture of 500 nL of taxol (20 mM) and its precursor, baccatin III (30 mM), is separated using such a column with a Tris buffer. PMID:11354480

  1. Ultrasound assisted enzyme catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate.

    PubMed

    Waghmare, Govind V; Vetal, Mangesh D; Rathod, Virendra K

    2015-01-01

    The present work illustrates the transesterification of glycerol to glycerol carbonate (GlyC) from dimethyl carbonate (DMC) using commercial immobilized lipase (Novozym 435) under ultrasonic irradiation. The experiments were performed in a batch reactor placed in an ultrasonic water bath using a sequence of experimental protocol to evaluate the effects of temperature, molar ratios of substrates, enzyme loading, duty cycle and ultrasound power on the conversion of glycerol to GlyC. It has been found that ultrasound-assisted lipase-catalyzed transesterification of glycerol would be a potential alternative to conventional alkali-catalyzed method, as high conversion (99.75%) was obtained at mild operating conditions: molar ratio of DMC to glycerol 3:1, catalyst amount of 13% (w/w), lower power input (100W), duty cycle 50% and temperature (60°C) in a relatively short reaction time (4h) using Novozym 435 as catalyst. Ultrasound reduces the reaction time up to 4h as compared to conventional stirring method (14h) catalyzed by Novozym 435. The repeated use of the catalyst under the optimum experimental condition resulted in decay in both enzyme activity and product conversion. PMID:25069889

  2. Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

    NASA Astrophysics Data System (ADS)

    Nwachukwu, Raymond E. S.

    In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

  3. Automated Parallel Capillary Electrophoretic System

    DOEpatents

    Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

    2000-02-22

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  4. Carbon nanotube patterning with capillary micromolding of catalyst.

    PubMed

    Lee, Jaewon; Ryu, Choonghan; Lee, Sungwoo; Jung, Donggeun; Kim, Hyoungsub; Chae, Heeyeop

    2007-11-01

    Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700 approximately 800 degrees C by PECVD process using CH4 and Ar gas in a scale of approximately 10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy. PMID:18047145

  5. Transversally periodic solitary gravity-capillary waves.

    PubMed

    Milewski, Paul A; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922

  6. Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Scoffield, Jessica; Silo-Suh, Laura

    2016-08-01

    Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation. PMID:27392247

  7. Measuring glycerol turnover, gluconeogenesis from glycerol, and total gluconeogenesis with [2-13C] glycerol: role of the infusion-sampling mode.

    PubMed

    Peroni, O; Large, V; Odeon, M; Beylot, M

    1996-07-01

    Mass isotopomer distribution analysis (MIDA) of glucose during infusion of [2-13C]glycerol is a new method for measuring total gluconeogenesis (GNG). Since this method relies on calculation of the isotopic enrichment (IE) of hepatic triose phosphates (TP), the results should be independent of the sites of tracer infusion and blood sampling. Postabsorptive and starved rats were infused with [2-13C]glycerol and sampled either in the arterial-venous (A-V) or venous-arterial (V-A) modes. Blood was also sampled from the portal vein. In both postabsorptive and starved rats, glycerol turnover rate (Rt) and the percent contribution of glycerol to total glucose production were higher in the A-V mode than in the V-A mode (P < .05). Glycerol IE in portal venous blood was intermediate between IE values observed in peripheral arterial and venous blood. Its use for calculating the contribution of glycerol to glucose production reconciled the results obtained with the two infusion-sampling modes in both postabsorptive and starved rats; this contribution was increased by starvation (P < .01). In postabsorptive rats, total GNG calculated from MIDA of glucose accounted for approximately 50% of glucose production whatever the infusion-sampling mode (A-V, 48.8% +/- 4.7%; V-A, 52.2% +/- 3.9%). This contribution increased to 90% in starved rats, again, with no difference between A-V (95.2% +/- 1.8%) and V-A (89.2% +/- 1.3%) modes. In conclusion, during infusion of [2-13C]glycerol, total GNG measured from MIDA of glucose is independent of the infusion-sampling mode, contrary to calculations of Rt and GNG from glycerol. Measurement of glycerol IE in portal venous blood reconciles the results obtained with the two modes with respect to the contribution of glycerol to GNG. PMID:8692028

  8. Capillary reference half-cell

    DOEpatents

    Hall, S.H.

    1996-02-13

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods. 11 figs.

  9. Capillary reference half-cell

    DOEpatents

    Hall, Stephen H.

    1996-01-01

    The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods.

  10. Coaxial capillary and conductive capillary interfaces for collection of fractions isolated by capillary electrophoresis

    SciTech Connect

    Chiu, R.W.; Walker, K.L.; Hagen, J.J.; Monning, C.A.; Wilkins, C.L.

    1995-11-15

    An instrument is described that allows the automated collection of fractions isolated by capillary electrophoresis. This instrument allows the electrical connection to be established with the separation capillary by using a coaxial capillary flow cell or by treating the outer surface of the capillary with a gold-filled epoxy to allow electrophoresis. The coaxial interface is most useful when the electroosmotic flow in the capillary is small, and the conductive capillary interface is favored when dilution and contamination of the sample must be minimized. Both geometries permit closely spaced fractions to be acquired with minimal cross-contamination and dilution. Sample recoveries were better than 80% and virtually independent of the chemical characteristics of the sample. Fractions isolated with this instrument were successfully analyzed by high-pressure liquid chromatography and electrospray mass spectrometry. 25 refs., 4 figs.

  11. Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism

    SciTech Connect

    Yeh, Joanne I.; Chinte, Unmesh; Du, Shoucheng

    2008-04-02

    Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 {angstrom} resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerol uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes.

  12. Borrelia burgdorferi Requires Glycerol for Maximum Fitness During The Tick Phase of the Enzootic Cycle

    PubMed Central

    Pappas, Christopher J.; Iyer, Radha; Petzke, Mary M.; Caimano, Melissa J.; Radolf, Justin D.; Schwartz, Ira

    2011-01-01

    Borrelia burgdorferi, the spirochetal agent of Lyme disease, is a vector-borne pathogen that cycles between a mammalian host and tick vector. This complex life cycle requires that the spirochete modulate its gene expression program to facilitate growth and maintenance in these diverse milieus. B. burgdorferi contains an operon that is predicted to encode proteins that would mediate the uptake and conversion of glycerol to dihydroxyacetone phosphate. Previous studies indicated that expression of the operon is elevated at 23°C and is repressed in the presence of the alternative sigma factor RpoS, suggesting that glycerol utilization may play an important role during the tick phase. This possibility was further explored in the current study by expression analysis and mutagenesis of glpD, a gene predicted to encode glycerol 3-phosphate dehydrogenase. Transcript levels for glpD were significantly lower in mouse joints relative to their levels in ticks. Expression of GlpD protein was repressed in an RpoS-dependent manner during growth of spirochetes within dialysis membrane chambers implanted in rat peritoneal cavities. In medium supplemented with glycerol as the principal carbohydrate, wild-type B. burgdorferi grew to a significantly higher cell density than glpD mutant spirochetes during growth in vitro at 25°C. glpD mutant spirochetes were fully infectious in mice by either needle or tick inoculation. In contrast, glpD mutants grew to significantly lower densities than wild-type B. burgdorferi in nymphal ticks and displayed a replication defect in feeding nymphs. The findings suggest that B. burgdorferi undergoes a switch in carbohydrate utilization during the mammal to tick transition. Further, the results demonstrate that the ability to utilize glycerol as a carbohydrate source for glycolysis during the tick phase of the infectious cycle is critical for maximal B. burgdorferi fitness. PMID:21750672

  13. Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism

    PubMed Central

    Yeh, Joanne I.; Chinte, Unmesh; Du, Shoucheng

    2008-01-01

    Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 Å resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerol uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes. PMID:18296637

  14. Alveolar Capillary Dysplasia

    PubMed Central

    Stankiewicz, Pawel; Steinhorn, Robin H.

    2011-01-01

    Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder. PMID:21471096

  15. Rotation of ultrasonically levitated glycerol drops

    NASA Technical Reports Server (NTRS)

    Biswas, A.; Leung, E. W.; Trinh, E. H.

    1991-01-01

    Ultrasonic levitation is used to suspend single millimeter-size glycerol drops in a rectangular chamber. Audio-frequency laterally standing waves set up in the chamber are used to torque the suspended drops. The shape evolution of the drop under the combined effect of centrifugal forces and the acoustic radiation stress, along with its angular velocity are monitored, using video imaging and light scattering techniques. The results show good qualitative agreement with the theoretically predicted shape evolution as a function of angular velocity.

  16. Capillary suspensions: Particle networks formed through the capillary force

    PubMed Central

    Koos, Erin

    2014-01-01

    The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review. PMID:25729316

  17. Tapered capillary optics

    DOEpatents

    Hirsch, Gregory

    1998-01-01

    A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

  18. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

    A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

  19. Current role of capillary electrophoretic/electrokinetic techniques in forensic toxicology.

    PubMed

    Tagliaro, Franco; Bortolotti, Federica; Pascali, Jennifer P

    2007-08-01

    The current application of capillary electrophoresis in forensic toxicology has been critically reviewed with special focus on the areas where this technique has shown real advantages over chromatographic methods. For example, capillary electrophoresis has been most successfully applied to the chiral analysis of some drugs of forensic interest, including amphetamines and their congeners. Another typical application field of capillary electrophoresis is represented by protein analysis. Recently, special interest has been paid to carbohydrate deficient transferrin (CDT), the most important biological marker of chronic alcohol abuse. Other specific applications of capillary electrophoresis of potential forensic toxicological concern are also discussed. The review includes 62 references. PMID:17572886

  20. Ruminal fermentation of propylene glycol and glycerol.

    PubMed

    Trabue, Steven; Scoggin, Kenwood; Tjandrakusuma, Siska; Rasmussen, Mark A; Reilly, Peter J

    2007-08-22

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h, all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in decreasing order, all increased with incubation time. Addition of any of the three substrates somewhat decreased acetate formation, while addition of either propylene glycol increased propionate formation but decreased that of butyrate. R- and S-propylene glycol did not differ significantly in either their rates of disappearance or the products formed when they were added to the fermentation medium. Fermentations of rumen fluid containing propylene glycol emitted the sulfur-containing gases 1-propanethiol, 1-(methylthio)propane, methylthiirane, 2,4-dimethylthiophene, 1-(methylthio)-1-propanethiol, dipropyl disulfide, 1-(propylthio)-1-propanethiol, dipropyl trisulfide, 3,5-diethyl-1,2,4-trithiolane, 2-ethyl-1,3-dithiane, and 2,4,6-triethyl-1,3,5-trithiane. Metabolic pathways that yield each of these gases are proposed. The sulfur-containing gases produced during propylene glycol fermentation in the rumen may contribute to the toxic effects seen in cattle when high doses are administered for therapeutic purposes. PMID:17655323

  1. Isolation of the human Xp21 glycerol kinase gene by positional cloning.

    PubMed

    Walker, A P; Muscatelli, F; Monaco, A P

    1993-02-01

    The gene for human glycerol kinase deficiency (GK) maps in Xp21.3 in a critical region of about 50-250 kb located distal to the Duchenne muscular dystrophy gene (DMD) by analysis of patient deletions and YAC contigs. We have used a genomic exon amplification strategy to isolate potential exons from two cosmids which mapped to this interval. The genomic exons were used to isolate six overlapping cDNA clones from human fetal liver which encode the X-linked glycerol kinase gene. The cDNA clones map to cosmids, YAC clones and deletions in patients which define the GK critical region and also hybridize to several autosomal fragments and one Xq fragment in genomic DNA. The GK gene is expressed most in human liver with three transcript sizes of 1.85, 2.7, and 3.7 kb. Sequence analysis of 1.5 kb of several overlapping liver cDNA clones predicted a protein with approximately 63% similarity to the E. coli and B. subtilis glycerol kinase genes. The liver cDNA clones have sequence identity with four genomic exons and the 3' untranslated region from an Xp21.3 cosmid thus indicating that this is the expressed GK gene which when deleted in patients gives rises to GK deficiency. PMID:8499898

  2. The order of condensation in capillary grooves.

    PubMed

    Rascón, Carlos; Parry, Andrew O; Nürnberg, Robert; Pozzato, Alessandro; Tormen, Massimo; Bruschi, Lorenzo; Mistura, Giampaolo

    2013-05-15

    We consider capillary condensation in a deep groove of width L. The transition occurs at a pressure p(co)(L) described, for large widths, by the Kelvin equation p(sat) - p(co)(L) = 2σ cosθ/L, where θ is the contact angle at the side walls and σ is the surface tension. The order of the transition is determined by the contact angle of the capped end θcap; it is continuous if the liquid completely wets the cap, and first-order otherwise. When the transition is first-order, corner menisci at the bottom of the capillary lead to a pronounced metastability, determined by a complementary Kelvin equation Δp(L) = 2σ sinθcap/L. On approaching the wetting temperature of the capillary cap, the corner menisci merge and a single meniscus unbinds from the bottom of the groove. Finite-size scaling shifts, crossover behaviour and critical singularities are determined at mean-field level and beyond. Numerical and experimental results showing the continuous nature of condensation for θcap = 0 and the influence of corner menisci on adsorption isotherms are presented. PMID:23611878

  3. Noise suppressing capillary separation system

    DOEpatents

    Yeung, E.S.; Xue, Y.

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans. 13 figs.

  4. Capillary optics for radiation focusing

    SciTech Connect

    Peurrung, A.J.; Reeder, P.L.; Bliss, M.; Craig, R.A.; Lepel, E.A.; Stromswold, D.C.; Stoffels, J.; Sunberg, D.S.; Tenny, H.

    1996-11-01

    Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using {sup 58}Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics.

  5. Biomedical applications of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  6. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    PubMed Central

    Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Árpád

    2013-01-01

    Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis. PMID:24312804

  7. Urea, glycolic acid, and glycerol in an organic residue produced by ultraviolet irradiation of interstellar/pre-cometary ice analogs.

    PubMed

    Nuevo, Michel; Bredehöft, Jan Hendrik; Meierhenrich, Uwe J; d'Hendecourt, Louis; Thiemann, Wolfram H-P

    2010-03-01

    More than 50 stable organic molecules have been detected in the interstellar medium (ISM), from ground-based and onboard-satellite astronomical observations, in the gas and solid phases. Some of these organics may be prebiotic compounds that were delivered to early Earth by comets and meteorites and may have triggered the first chemical reactions involved in the origin of life. Ultraviolet irradiation of ices simulating photoprocesses of cold solid matter in astrophysical environments have shown that photochemistry can lead to the formation of amino acids and related compounds. In this work, we experimentally searched for other organic molecules of prebiotic interest, namely, oxidized acid labile compounds. In a setup that simulates conditions relevant to the ISM and Solar System icy bodies such as comets, a condensed CH(3)OH:NH(3) = 1:1 ice mixture was UV irradiated at approximately 80 K. The molecular constituents of the nonvolatile organic residue that remained at room temperature were separated by capillary gas chromatography and identified by mass spectrometry. Urea, glycolic acid, and glycerol were detected in this residue, as well as hydroxyacetamide, glycerolic acid, and glycerol amide. These organics are interesting target molecules to be searched for in space. Finally, tentative mechanisms of formation for these compounds under interstellar/pre-cometary conditions are proposed. PMID:20402585

  8. Functional characterization of Yersinia pestis aerobic glycerol metabolism.

    PubMed

    Willias, Stephan P; Chauhan, Sadhana; Motin, Vladimir L

    2014-11-01

    Yersinia pestis biovar Orientalis isolates have lost the capacity to ferment glycerol. Herein we provide experimental validation that a 93 bp in-frame deletion within the glpD gene encoding the glycerol-3-phosphate dehydrogenase present in all biovar Orientalis strains is sufficient to disrupt aerobic glycerol fermentation. Furthermore, the inability to ferment glycerol is often insured by a variety of additional mutations within the glpFKX operon which prevents glycerol internalization and conversion to glycerol-3-phosphate. The physiological impact of functional glpFKX in the presence of dysfunctional glpD was assessed. Results demonstrate no change in growth kinetics at 26 °C and 37 °C. Mutants deficient in glpD displayed decreased intracellular accumulation of glycerol-3-phosphate, a characterized inhibitor of cAMP receptor protein (CRP) activation. Since CRP is rigorously involved in global regulation Y. pestis virulence, we tested a possible influence of a single glpD mutation on virulence. Nonetheless, subcutaneous and intranasal murine challenge was not impacted by glycerol metabolism. As quantified by crystal violet assay, biofilm formation of the glpD-deficient KIM6+ mutant was mildly repressed; whereas, chromosomal restoration of glpD in CO92 resulted in a significant increase in biofilm formation. PMID:25220241

  9. Synthesis and applications of {sup 13}C glycerol

    SciTech Connect

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  10. Degradation rates of glycerol polyesters at acidic and basic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

  11. The Acrylation of Glycerol: a Precursor to Functionalized Lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K2O as catalyst. This reaction was carried out in hexane in a closed stainless steel reactor at 200°C for 5h. The reactants were added in a 1:3:4 glycerol:decanoic acid:acrylic acid molar ratio. The resu...

  12. Biodegradation of Glycerol Trinitrate and Pentaerythritol Tetranitrate by Agrobacterium radiobacter

    PubMed Central

    White, G. F.; Snape, J. R.; Nicklin, S.

    1996-01-01

    Bacteria capable of metabolizing highly explosive and vasodilatory glycerol trinitrate (GTN) were isolated under aerobic and nitrogen-limiting conditions from soil, river water, and activated sewage sludge. One of these strains (from sewage sludge) chosen for further study was identified as Agrobacterium radiobacter subgroup B. A combination of high-pressure liquid chromatography and nuclear magnetic resonance analyses of the culture medium during the growth of A. radiobacter on basal salts-glycerol-GTN medium showed the sequential conversion of GTN to glycerol dinitrates and glycerol mononitrates. Isomeric glycerol 1,2-dinitrate and glycerol 1,3-dinitrate were produced simultaneously and concomitantly with the disappearance of GTN, with significant regioselectivity for the production of the 1,3-dinitrate. Dinitrates were further degraded to glycerol 1- and 2-mononitrates, but mononitrates were not biodegraded. Cells were also capable of metabolizing pentaerythritol tetranitrate, probably to its trinitrate and dinitrate analogs. Extracts of broth-grown cells contained an enzyme which in the presence of added NADH converted GTN stoichiometrically to nitrite and the mixture of glycerol dinitrates. The specific activity of this enzyme was increased 160-fold by growth on GTN as the sole source of nitrogen. PMID:16535244

  13. Fabrication of a glycerol from CO2 reaction system, supplement

    NASA Technical Reports Server (NTRS)

    Weiss, A. H.

    1973-01-01

    The fabrication, installation, and testing of a glycerol hydrogenation and a CO2 hydrogenation - CH4 partial oxidation units are reported. The glycerol system proved to be operational while the CO2 system was installed but not bought on operational steam.

  14. Transketolase activity modulates glycerol-3-phosphate levels in Escherichia coli.

    PubMed

    Vimala, A; Harinarayanan, R

    2016-04-01

    Transketolase activity provides an important link between the metabolic pathways of glycolysis and pentose phosphate shunt and catalyzes inter-conversions between pentose phosphates and glycolytic intermediates. It is widely conserved in life forms. A genetic screen for suppression of the growth defect of Escherichia coli tktA tktB mutant in LB medium revealed two mutations, one that rendered the glpK expression constitutive and another that inactivated deoB. Characterizing these mutations aided in uncovering the role of ribose-5-P (a transketolase substrate) as an inhibitor of glycerol assimilation and de novo glycerol-3-P synthesis. Using lacZ fusions, we show that ribose-5-P enhances GlpR-mediated repression of the glpFKX operon and inhibits glycerol assimilation. Electrophoretic Mobility Shift Assay (EMSA) showed ribose-5-P made the DNA-GlpR complex less sensitive to the inducer glycerol-3-P. In addition to inhibition of glycerol assimilation, obstruction of ribose-5-P metabolism retards growth from glycerol-3-P limitation. Glucose helps to overcome this limitation through a mechanism involving catabolite repression. To our knowledge, this report is the first to show ribose-5-P can modulate glycerol-3-P concentration in the cell by regulation of glycerol assimilation as well as its de novo synthesis. This regulation could be prevalent in other organisms. PMID:26691989

  15. THERMOPLASTIC STARCH-KRAFT LIGNIN-GLYCEROL BLENDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-kraft lignin-glycerol blends were extruded in a twin-screw extruder to produce non-brittle films. One week after extrusion, films with a mid-range composition of 52% starch, 20% lignin, and 28% glycerol showed a tensile strength at break of 2.8 MPa, Young's modulus of 48 MPa, and elongation ...

  16. PREPARATION AND CHARACTERIZATION OF 4-METHOXY CINNAMOYL GLYCEROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol was combined with cinnamic acid to prepare the corresponding ester, glycerol cinnamate. Conversions of 81% were achieved after 16 hr in toluene at reflux conditions. The product was recovered by extraction with distilled water and diethyl ether. The isolated product displayed strong abso...

  17. A capillary Archimedes' screw

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Dorbolo, Stephane

    2014-11-01

    As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a drop pending on a rotating spiral which is tilted toward the horizontal. The ascent of the drop to the top of the spiral is considered and a theoretical model based on geometrical considerations is proposed. The climb of the drop is limited by the fluid deposition on the screw at high capillary number and by a centrifugation phenomenon. We find out the range of fluid proprities and spiral characteristics for which an ascending motion of the drop is possible. Finally we discuss the efficiency of such system to extract a fluid from a bath at a centrimetric scale.

  18. Steady Capillary Driven Flow

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M.

    1996-01-01

    A steady capillary driven flow is developed for a liquid index in a circular tube which is partially coated with a surface modifier to produce a discontinuous wetting condition from one side of the tube to the other. The bulk flow is novel in that it is truly steady, and controlled solely by the physics associated with dynamic wetting. The influence of gravity on the flow is minimized through the use of small diameter tubes approximately O(1 mm) tested horizontally in a laboratory and larger tubes approximately O(10 mm) tested in the low gravity environment of a drop tower. Average steady velocities are predicted and compared against a large experimental data set which includes the effects of tube dimensions and fluid properties. The sensitivity of the velocity to surface cleanliness is dramatic and the advantages of experimentation in a microgravity environment are discussed.

  19. Capillary interconnect device

    DOEpatents

    Renzi, Ronald F.

    2007-12-25

    A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) means for applying an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

  20. Glycerol, an underestimated flavor precursor in the Maillard reaction.

    PubMed

    Smarrito-Menozzi, Candice; Matthey-Doret, Walter; Devaud-Goumoens, Stéphanie; Viton, Florian

    2013-10-30

    The objective of the present work was to investigate in depth the role of glycerol in Maillard reactions and its potential to act as an active flavor precursor. Reactions using isotopically labeled compounds (various reducing sugars, proline, and glycerol) unambiguously demonstrated that, in addition to its role of solvent, glycerol actively contributes to the formation of proline-specific compounds in Maillard model systems. Additionally, rhamnose and fucose/proline/glycerol systems generated the 2-propionyl-1(3),4,5,6-tetrahydropyridines, known for their roasty, popcorn aroma. Their formation from such systems is unprecedented. The results presented here have direct implications for flavor generation during thermal processing of foods containing glycerol, which is a ubiquitous food ingredient and an underestimated flavor precursor. PMID:23373461

  1. Microbial conversion of glycerol to 1,3-propanediol

    SciTech Connect

    Zeng, A.P.; Biebl, H.; Deckwer, W.D.

    1996-10-01

    Glycerol is a byproduct from the soap and detergent industry and possibly from future biodiesel plants. The conversion of glycerol to 1,3-propanediol (PD) is of industrial interest due to the potential use of PD for the synthesis of polyesters. We have been studying the microbial conversion of glycerol to PD with work ranging from strain isolation, medium optimization, pathway analysis, product formation kinetics and growth modeling, downstream processing and reactor scale-up (up to 2000 1). PD yields of nearly 100% of the theoretical maximum (0.72 mol/mol glycerol) and final product concentrations of about 65 g/l were achieved with both Klebsiella pneumoniae and Clostridium butyricum. In addition to summarizing our experimental results the advances of bioconversion of glycerol will be reviewed in this presentation, with emphasis on discussing further research and development needs in this area. Results of process engineering and cost analysis will also be presented.

  2. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, E.S.; Chang, H.T.; Fung, E.N.

    1997-12-09

    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.

  3. Capillaries for use in a multiplexed capillary electrophoresis system

    SciTech Connect

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.

    1997-12-09

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

  4. Toxic and osmotic effects of glycerol on human granulocytes

    SciTech Connect

    Armitage, W.J.; Mazur, P.

    1984-11-01

    Human granulocytes are damaged by exposure to concentrations of glycerol as low as 0.5 M. We therefore investigated the addition of glycerol to granulocytes and its subsequent dilution under various conditions to try to distinguish between toxic and harmful osmotic effects of glycerol. The lesion caused by glycerol at 0/sup 0/C was expressed as a loss of plasma membrane integrity (as visualized by fluorescein diacetate) only after incubation (greater than or equal to1 h) at 37/sup 0/C. This damage was not ameliorated when osmotic stress was lessened by reducing the rates of addition and dilution of glycerol to keep the computed cell volume within 80-170% of isotonic cell volume. However, when osmotic stress was reduced further by increasing the temperature of addition and dilution of glycerol from 0/sup 0/ to 22/sup 0/C, the tolerance of the cells to 1 M glycerol increased somewhat. Reducing exposure to glycerol to 3 min or less at 0/sup 0/C greatly increased survival, but this time was too short to allow glycerol to equilibrate intracellularly. Finally, the presence of extra impermeant solute (NaCl or sucrose) in the medium to reduce the equilibrium cell volume to 60% of isotonic cell volume enabled granulocytes to survive 30-min exposure to 1 M glycerol at 0/sup 0/C, but cells had to remain shrunken during the 37/sup 0/C incubation to prevent the loss of membrane integrity. Suspensions that contained damaged granulocytes formed aggregates when incubated at 37/sup 0/C, and these aggregates were responsible for a major fraction of the observed loss in viability.

  5. On singularities of capillary surfaces in the absence of gravity

    DOE PAGESBeta

    Roytburd, V.

    1983-01-01

    We smore » tudy numerical solutions to the equation of capillary surfaces in trapezoidal domains in the absence of gravity when the boundary contact angle declines from 90 ° to some critical value. We also discuss a result on the behavior of solutions in more general domains that confirms numerical calculations.« less

  6. Applications of capillary optical fibers

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard

    2006-10-01

    The paper updates and summarizes contemporary applications of capillary optical fibers. Some of these applications are straight consequence of the classical capillary properties and capillary devices like: rheometry, electrophoresis, column chromatography (gas and liquid). Some new applications are tightly connected with co-propagation (or counter-propagation) of micro-mass together with optical wave - evanescent or of considerable intensity. In the first case, the optical wave is propagated in a narrow (more and more frequently single-mode) optical ring core adjacent to the capillary hole. The optical propagation is purely refractive. In the second case, the intensity maximum of optical wave is on the capillary long axis, i.e. in the center of the hole. The optical propagation is purely photonic, i.e. in a Bragg waveguide (one dimensional photonic band-gap). The capillary hole is filled with vacuum or with propagated matter (gas, liquid, single atoms, continuous particle arrangement). Optical capillaries, filamentary and embedded, are turning to a fundamental component of nano- and micro-MOEMS.

  7. Instability of the capillary bridge

    NASA Astrophysics Data System (ADS)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  8. Feruloyl glycerol and 1,3-diferuloyl glycerol antioxidant behavior in phospholipid vesicles.

    PubMed

    Evans, Kervin O; Compton, David L; Laszlo, Joseph A; Appell, Michael

    2016-02-01

    Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (F2G), the by-product of biocatalytic transesterification soybean oil and ethyl ferulate, were examined for their behavior in phospholipid vesicles. Based on absorbance and fluorescence methods, FG and F2G both were found to partition into vesicles and incorporate well into 1,2-dioleoylphosphocholine (DOPC) vesicles. FG and F2G incorporation resulted in vesicles that were as or slightly more stable than the unloaded vesicles. FG and F2G both demonstrated the ability to maintain antioxidant properties within the lipid bilayer. Bilayer depth analysis was conducted using the parallax method and molecular modeling. PMID:26561732

  9. Renewable chemicals: dehydroxylation of glycerol and polyols.

    PubMed

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-08-22

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  10. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols

    PubMed Central

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-01-01

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  11. Integrated multiplexed capillary electrophoresis system

    SciTech Connect

    Yeung, Edward S.; Tan, Hongdong

    2002-05-14

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

  12. Design and analysis of biorefineries based on raw glycerol: addressing the glycerol problem.

    PubMed

    Posada, John A; Rincón, Luis E; Cardona, Carlos A

    2012-05-01

    Glycerol as a low-cost by-product of the biodiesel industry can be considered a renewable building block for biorefineries. In this work, the conversion of raw glycerol to nine added-value products obtained by chemical (syn-gas, acrolein, and 1,2-propanediol) or bio-chemical (ethanol, 1,3-propanediol, d-lactic acid, succinic acid, propionic acid, and poly-3-hydroxybutyrate) routes were considered. The technological schemes for these synthesis routes were designed, simulated, and economically assessed using Aspen Plus and Aspen Icarus Process Evaluator, respectively. The techno-economic potential of a glycerol-based biorefinery system for the production of fuels, chemicals, and plastics was analyzed using the commercial Commercial Sale Price/Production Cost ratio criteria, under different production scenarios. More income can be earned from 1,3-propanediol and 1,2-propanediol production, while less income would be obtained from hydrogen and succinic acid. This analysis may be useful mainly for biodiesel producers since several profitable alternatives are presented and discussed. PMID:22349197

  13. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    NASA Astrophysics Data System (ADS)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  14. Glycerol dynamics in weight-losing cancer patients.

    PubMed

    Edén, E; Edström, S; Bennegárd, K; Lindmark, L; Lundholm, K

    1985-02-01

    This study was designed to show whether weight-losing cancer patients have an elevated glycerol turnover. Four groups of patients were examined: weight-losing cancer patients, weight-losing patients without cancer, cancer patients without weight loss, and weight-stable and well-nourished hospitalized control patients. Glycerol was infused intravenously at three different rates (200, 400, and 800 mumol/hr/kg body weight) after an overnight fast. This allowed measurement of clearance and plasma glycerol turnover. Weight-losing cancer patients (group 1) had an almost threefold higher glycerol turnover per kilogram of body weight compared with malnourished and well-nourished noncancer patients. However, both malnourished cancer and noncancer patients had an elevated glycerol turnover compared with well-nourished patients when glycerol turnover was related to whole body lipids. The results how that progressive clinical cancer is associated with an elevated plasma glycerol turnover, probably indicating an increased whole body lipolysis. This may explain the loss of body fat during the development of cancer cachexia. PMID:4038560

  15. Capillary and microchip electrophoretic analysis of polycyclic aromatic hydrocarbons.

    PubMed

    Ferey, Ludivine; Delaunay, Nathalie

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants which can reach the environment and food in different ways. Because of their high toxicity, two international regulatory institutions, the US Environmental Protection Agency and the European Food Safety Authority, have classified PAHs as priority pollutants, generating an important demand for the detection and identification of PAHs. Thus, sensitive, fast, and cheap methods for the analysis of PAHs in environmental and food samples are urgently needed. Within this context, electrophoresis, in capillary or microchip format, displays attractive features. This review presents and critically discusses the published literature on the different approaches to capillary and microchip electrophoresis analysis of PAHs. PMID:25542576

  16. Surface Tension and Capillary Rise

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1972-01-01

    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  17. 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.

  18. Capillary electrophoresis electrospray ionization mass spectrometry interface

    SciTech Connect

    Smith, R.D.; Severs, J.C.

    1999-11-30

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

  19. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

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

  20. Optimization of medium composition for erythritol production from glycerol by Yarrowia lipolytica using response surface methodology.

    PubMed

    Rywińska, Anita; Marcinkiewicz, Marta; Cibis, Edmund; Rymowicz, Waldemar

    2015-08-18

    Several factors affecting erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 strain were examined in batch fermentations. Ammonium sulfate, monopotassium phosphate, and sodium chloride were identified as critical medium components that determine the ratio of polyols produced. The central composite rotatable experimental design was used to optimize medium composition for erythritol production. The concentrations of ammonium sulfate, monopotassium phosphate, and sodium chloride in the optimized medium were 2.25, 0.22, and 26.4 g L(-1), respectively. The C:N ratio was found as 81:1. In the optimized medium with 100 g L(-1) of glycerol the Wratislavia K1 strain produced 46.9 g L(-1) of erythritol, which corresponded to a 0.47 g g(-1) yield and a productivity of 0.85 g L(-1) hr(-1). In the fed-batch mode and medium with the total concentration of glycerol at 300 g L(-1) and C:N ratio at 81:1, 132 g L(-1) of erythritol was produced with 0.44 g g(-1) yield and a productivity of 1.01 g L(-1) hr(-1.) PMID:25387364

  1. Glycerol uptake is by passive diffusion in the heart but by facilitated transport in RBCs at high glycerol levels in cold acclimated rainbow smelt (Osmerus mordax).

    PubMed

    Clow, Kathy A; Driedzic, William R

    2012-04-15

    Rainbow smelt (Osmerus mordax) is a small fish that accumulates glycerol at low winter seawater temperatures. In laboratory-held fish, glycerol concentration typically reaches 225 mM in plasma and in all cells. Glycerol uptake by the heart and red blood cells (RBCs) was assessed by tracking [(14)C(U)]glycerol into the acid-soluble pool. In fish acclimated to 9-10°C a decrease in perfusion/incubation temperature from 8 to 1°C resulted in a decrease in glycerol uptake with a Q(10) of 3.2 in heart and 2.4 in RBCs. Acclimation to ∼1.5°C did not result in an adaptive enhancement of glycerol uptake as rates were unchanged in heart and RBCs. Glycerol uptake at 1°C was by passive diffusion in heart as evidenced by a linear relationship between glycerol uptake and extracellular glycerol concentration and a lack of inhibition by phloretin. In contrast, in RBCs, glycerol uptake with respect to glycerol concentration showed two linear relationships with a transition point around 50 mM extracellular glycerol. The slope of the second phase was much steeper and eliminated with the inclusion of phloretin. In RBCs from Atlantic salmon (Salmo salar), a related species that does not accumulate glycerol, glycerol uptake showed only a single linear curve and was not inhibited by phloretin. The data imply a strong facilitated component to glycerol uptake in rainbow smelt RBCs at high glycerol concentrations. We propose this is related to cyclic changes in RBC glycerol content involving a loss of glycerol at the gill and a reaccumulation during passage through the liver. PMID:22319051

  2. Gravity-Capillary Lumps

    NASA Astrophysics Data System (ADS)

    Akylas, Triantaphyllos R.; Kim, Boguk

    2004-11-01

    In dispersive wave systems, it is known that 1-D plane solitary waves can bifurcate from linear sinusoidal wavetrains at particular wave numbers k = k0 where the phase speed c(k) happens to be an extremum (dc/dk| _0=0) and equals the group speed c_g(k_0). Two distinct possibilities thus arise: either the extremum occurs in the long-wave limit (k_0=0) and, as in shallow water, the bifurcating solitary waves are of the KdV type; or k0 ne 0 and the solitary waves are in the form of packets, described by the NLS equation to leading order, as for gravity-capillary waves in deep water. Here it is pointed out that an entirely analogous scenario is valid for the genesis of 2-D solitary waves or `lumps'. Lumps also may bifurcate at extrema of the phase speed and do so when 1-D solitary waves happen to be unstable to transverse perturbations; moreover, they have algebraically decaying tails and are either of the KPI type (e.g. in shallow water in the presence of strong surface tension) or of the wave packet type (e.g. in deep water) and are described by an elliptic-elliptic Davey-Stewartson equation system to leading order. Examples of steady lump profiles are presented and their dynamics is discussed.

  3. Flow rate limitation in open capillary channel flows.

    PubMed

    Haake, Dennis; Rosendahl, Uwe; Ohlhoff, Antje; Dreyer, Michael E

    2006-09-01

    This paper reports the experimental and theoretical investigations of forced liquid flows through open capillary channels under reduced gravity conditions. An open capillary channel is a structure that establishes a liquid flow path at low Bond numbers, when the capillary pressure caused by the surface tension force dominates in comparison to the hydrostatic pressure induced by gravitational or residual accelerations. In case of steady flow through the channel, the capillary pressure of the free surface balances the pressure difference between the liquid and the surrounding constant-pressure gas phase. Because of convective and viscous momentum transport, the pressure along the flow path decreases and causes the free surface to bend inward. The maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the geometry of the channel and the properties of the liquid. In this paper we present a comparison of the theoretical and experimental critical flow rates and surface profiles for convective dominated flows. For the prediction of the critical flow rate a one-dimensional theoretical model taking into account the entrance pressure loss and the frictional pressure loss in the channel is developed. PMID:17124140

  4. Filling of charged cylindrical capillaries.

    PubMed

    Das, Siddhartha; Chanda, Sourayon; Eijkel, J C T; Tas, N R; Chakraborty, Suman; Mitra, Sushanta K

    2014-10-01

    We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because of decreased velocity gradients at the wall. Both these effects essentially stem from the spontaneous formation of an electric double layer (EDL) and the resulting streaming potential caused by the net capillary-flow-driven advection of ionic species within the EDL. Our results demonstrate that filling of charged capillaries also exhibits the well-known linear and Washburn regimes witnessed for uncharged capillaries, although the filling rate is always lower than that of the uncharged capillary. We attribute this to a competitive success of the lowering of the driving forces (because of electroviscous effects), in comparison to the effect of weaker drag forces. We further reveal that the time at which the transition between the linear and the Washburn regime occurs may become significantly altered with the introduction of surface charges, thereby altering the resultant capillary dynamics in a rather intricate manner. PMID:25375597

  5. Production of rapamycin in Streptomyces hygroscopicus from glycerol-based media optimized by systemic methodology.

    PubMed

    Kim, Yong Hyun; Park, Bu Soo; Bhatia, Shashi Kant; Seo, Hyung-Min; Jeon, Jong-Min; Kim, Hyun-Joong; Yi, Da-Hye; Lee, Ju-Hee; Choi, Kwon-Young; Park, Hyung-Yeon; Kim, Yun-Gon; Yang, Yung-Hun

    2014-10-01

    Rapamycin, produced by the soil bacterium Streptomyces hygroscopicus, has the ability to suppress the immune system and is used as an antifungal, anti-inflammatory, antitumor, and immunosuppressive agent. In an attempt to increase the productivity of rapamycin, mutagenesis of wild-type Streptomyces hygroscopicus was performed using ultraviolet radiation, and the medium composition was optimized using glycerol (which is one of the cheapest starting substrates) by applying Plackett-Burman design and response surface methodology. Plackett-Burman design was used to analyze 14 medium constituents: M100 (maltodextrin), glycerol, soybean meal, soytone, yeast extract, (NH4)2SO4, L-lysine, KH2PO4, K2HPO4, NaCl, FeSO4·7H2O, CaCO3, 2-(N-morpholino) ethanesulfonic acid, and the initial pH level. Glycerol, soytone, yeast extract, and CaCO3 were analyzed to evaluate their effect on rapamycin production. The individual and interaction effects of the four selected variables were determined by Box-Behnken design, suggesting CaCO3, soytone, and yeast extract have negative effects, but glycerol was a positive factor to determine rapamycin productivity. Medium optimization using statistical design resulted in a 45% (220.7 ± 5.7 mg/l) increase in rapamycin production for the Streptomyces hygroscopicus mutant, compared with the unoptimized production medium (151.9 ± 22.6 mg/l), and nearly 588% compared with wildtype Streptomyces hygroscopicus (37.5 ± 2.8 mg/l). The change in pH showed that CaCO3 is a critical and negative factor for rapamycin production. PMID:25001557

  6. Capillary force in high aspect-ratio micropillar arrays

    NASA Astrophysics Data System (ADS)

    Chandra, Dinesh

    High aspect-ratio (HAR) micropillar arrays are important for many applications including, mechanical sensors and actuators, tunable wetting surfaces and substrates for living cell studies. However, due to their mechanical compliance and large surface area, the micropillars are susceptible to deformation due to surface forces, such as adhesive force and capillary force. In this thesis we have explored the capillary force driven mechanical instability of HAR micropillar arrays. We have shown that when a liquid is evaporated off the micropillar arrays, the pillars bend and cluster together due to a much smaller capillary meniscus interaction force while still surrounded by a continuous liquid body, rather than due to often reported Laplace pressure difference because of isolated capillary bridges. We have studied both theoretically and experimentally, the capillary force induced clustering behavior of micropillar arrays as a function of their elastic modulus. To this end, we have developed a modified replica molding process to fabricate a wide range of hydrogel micropillar arrays, whose elastic modulus in the wet state could be tuned by simply varying the hydrogel monomer composition. By minimizing the sum of capillary meniscus interaction energy and bending energy of the pillars in a cluster, we have derived a critical micropillar cluster size, which is inversely proportional to elastic modulus of micropillars. The estimated cluster size as a function of elastic modulus agrees well with our experimental observation. We have also explored the utility of the clustered micropillar arrays as ultrathin whitening layers mimicking the structural whitening mechanism found in some insects in nature. Finally, we have theoretically studied the capillary force induced imbibition of a liquid droplet on a model rough surface consisting of micropillar arrays. Our theoretical model suggests that due to shrinking liquid droplet, the imbibition dynamics does not follow the diffusive

  7. Capillary Flow Experiments Began on the International Space Station

    NASA Technical Reports Server (NTRS)

    J. Mark Hickman; Green, Robert D.

    2005-01-01

    The Capillary Flow Experiments (CFEs) are a suite of fluid physics flight experiments designed to investigate capillary flows and phenomena in low gravity. Data obtained from the CFEs will be crucial to NASA s Space Exploration Initiative, particularly pertaining to fluids management systems such as fuels and cryogen storage systems, thermal control systems (e.g., water recycling), and materials processing in the liquid state. NASA s current plans for exploration missions assume the use of larger liquid propellant masses than have ever flown on interplanetary missions. Under low-gravity conditions, capillary forces can be exploited to control fluid orientation so that such large mission-critical systems perform predictably. The first of the CFE experiments has been conducted on the International Space Station, and the data are being analyzed. The experiment suite is described briefly.

  8. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions

    PubMed Central

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source. PMID:25880041

  9. Glycerol administration before endurance exercise: metabolism, urinary glycerol excretion and effects on doping-relevant blood parameters.

    PubMed

    Koehler, Karsten; Braun, Hans; de Marees, Markus; Geyer, Hans; Thevis, Mario; Mester, Joachim; Schaenzer, Wilhelm

    2014-03-01

    Glycerol is prohibited as a masking agent by the World Anti-Doping Agency and a urinary threshold has recently been recommended. However, little is known about urinary glycerol excretion after exercise, when (1) exogenous glycerol is metabolized increasingly and (2) endogenous glycerol levels are elevated. The purpose of the placebo-controlled cross-over study was to determine the effects of pre-exercise glycerol administration on glycerol metabolism, urinary excretion, and selected blood parameters. After administration of glycerol (G; 1.0 g/kg body weight (BW) + 25 ml fluid/kg BW) or placebo (P; 25 ml fluid/kg), 14 cyclists exercised 90 min at 60% VO2max . Samples were taken at 0 h (before administration), 2.5 h (before exercise), 4 h (after exercise) and 6.5 h and additional urine samples were collected until 24 h. Exercise increased endogenous plasma glycerol (0.51 ± 0.21 mmol/l) but peak concentrations were much higher in G (2.5 h: 15.6 ± 7.8 mmol/l). Urinary glycerol increased rapidly (58,428 ± 71,084 µg/ml after 2.5 h) and was significantly higher than in P until 13.6 ± 0.9 h (p < 0.01). In comparison with placebo administration, G caused significantly greater changes in plasma volume and haemoglobin concentrations after 2.5 h. BW and urine production were significantly different between P and G after 2.5 h and post-exercise. Despite exercise-induced increases in endogenous glycerol in the control group, urinary excretion remained well below the previously recommended threshold. In addition, exercise-related glycerol degradation did not appear to negatively affect the detection of exogenously administered glycerol. PMID:23359436

  10. Capillary viscometer with a pressure sensor: a subject for student projects

    NASA Astrophysics Data System (ADS)

    Massalha, Taha; Digilov, Rafael M.

    2015-11-01

    We describe a vacuum-based pressure-detecting capillary viscometer for the viscosity determination of Newtonian fluids without known density. The viscometer operates on the principle that the variation in air pressure of the vacuum vessel p≤ft(t\\right) replaces the flow rate and pressure drop measurements which are usually required for the operation of a capillary tube viscometer. The mathematical expression for p≤ft(t\\right), found in the terms of the Lambert-W function, is used to fit the experimental data for viscosity determination. The results for viscosities of distilled water and 50 wt.% glycerol aqueous solution obtained under ambient temperature condition were compared to reference data and a good agreement was observed. The viscometer is suitable for undergraduate laboratories due to its low cost and simplicity in experimental setup. Moreover, the experimental with the vacuum vessel setup provides an in-depth understanding of fluid flow.

  11. Recent Advances in Glycerol Polymers: Chemistry and Biomedical Applications

    PubMed Central

    Zhang, Heng

    2015-01-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, we describe the underlying chemistry of glycerol, which provides access to a range of monomers for subsequent polymerizations. We then review the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth. Next, we describe several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity. Fourth, we describe the growing market opportunity for the use of polymers in medicine. Finally we conclude and summarize the findings, as well as discuss potential opportunities for continued research efforts. PMID:25308354

  12. Diffusion-viscosity decoupling in supercooled glycerol aqueous solutions.

    PubMed

    Trejo González, José A; Longinotti, M Paula; Corti, Horacio R

    2015-01-01

    The diffusion of ferrocene methanol in supercooled glycerol-water mixtures has been measured over a wide viscosity range, which allowed analyzing the composition dependence of the Stokes-Einstein breakdown (diffusion-viscosity decoupling). The observed decoupling exhibits a common behavior for all studied compositions (glycerol mass fractions between 0.7 and 0.9), determined by the reduced temperature (T/Tg) of the mixtures. This result differs from that reported previously for the diffusion of glycerol in its aqueous solutions, where the reduced temperature for the decoupling decreases with increasing water content. We conclude that the contradictory results are only apparent, and they can be explained by the use of inconsistent extrapolated values of the viscosity of the glycerol-water mixtures in the supercooled region. PMID:25478790

  13. Dehydration of glycerol over niobia-supported silicotungstic acid catalysts.

    PubMed

    Lee, Young Yi; Ok, Hye Jeong; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2013-01-01

    Liquid-phase dehydration of glycerol to acrolein over nanosized niobia-supported silicotungstic acid catalysts was performed to investigate the effect of the silicotungstic acid loading on the catalytic performance of the catalysts. The catalysts were prepared by following an impregnation method with different HSiW loadings in the range of 10-50 wt%. The prepared catalysts were characterized by N2 physisorption, XRD, FT-IR, TPD of ammonia, and TGA. Dehydration of glycerol was conducted in an autoclave reactor under the conditions of controlled reaction temperatures under corresponding pressure. Increasing HSiW loading rapidly increased the acidity of HSiW/Nb205 catalyst and rate of glycerol conversion, but acrolein selectivity decreased due to enhanced deactivation of the catalyst by carbon deposit. Consequently, it was confirmed that catalytic activity for the dehydration of glycerol to acrolein was dependant on the acidity of catalyst and can be controlled by HSiW loading. PMID:23646735

  14. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol

    PubMed Central

    Wu, Chunfei; Wang, Zichun; Williams, Paul T.; Huang, Jun

    2013-01-01

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm3 H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry. PMID:24067754

  15. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol.

    PubMed

    Wu, Chunfei; Wang, Zichun; Williams, Paul T; Huang, Jun

    2013-01-01

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm(3) H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry. PMID:24067754

  16. Plasma reforming of glycerol for synthesis gas production.

    PubMed

    Zhu, Xinli; Hoang, Trung; Lobban, Lance L; Mallinson, Richard G

    2009-05-28

    Glycerol can be effectively converted to synthesis gas (selectivity higher than 80%) with small amounts of water or no water using plasmas at low temperature and atmospheric pressure, without external heating. PMID:19436906

  17. Physicochemical characterization of oil palm mesocarp fibre treated with glycerol

    NASA Astrophysics Data System (ADS)

    Nor Hamizah M., A.; Roila, A.; Rahimi M., Y.

    2015-09-01

    Lignocellulose has been identified as another source for conversion into value added products. In the present work, physicochemical features from the oil palm mesocarp fibre treated by using pure glycerol with 2% (w/w) NaOH catalyst and crude glycerol have been studied. Treatment was conducted at temperatures 150 °C for 60 min. Fibre treated by crude glycerol resulted in high percentages of holocellulose and lower content of insoluble lignin. These results suggest that crude glycerol can be used as an alternative solvent for pretreatment process. The characterization treated fibre by means of FTIR and TGA has shown significant differences compared to untreated fibre. It was revealed that treated fibre successful eliminated hemicellulose and reduce of lignin content.

  18. A comparison of absorption of glycerol tristearate and glycerol trioleate by rat small intestine

    SciTech Connect

    Bergstedt, S.E.; Hayashi, H.; Kritchevsky, D.; Tso, P. )

    1990-09-01

    Generally, fats rich in saturated fatty acids raise serum cholesterol, whereas fats rich in polyunsaturated fatty acids lower it. There appear to be exceptions; e.g., stearic acid (18:0)-rich fats have little or no effect on serum cholesterol concentrations. This apparent lack of cholesterolemic effect of stearic acid-rich fat could be because intestinal absorption of fat is poor or subsequent plasma and/or tissue metabolism of fat is different. To investigate mechanisms involved, we compared intestinal digestion, uptake, and lymphatic transport of glycerol tristearate (TS) and glycerol trioleate (TO, 18:1). Two groups of rats bearing intestinal lymph fistulas were used. TO rats were fed intraduodenally for 8 h at a constant rate a lipid emulsion of 25 mumols/h of TO (labeled with glycerol tri(9,10 (n)-3H)oleate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline. TS rats were fed the same lipid emulsion except that TS replaced TO and the emulsion was labeled with glyceryl (1,3-14C)tristearate. The lymph triglyceride and radioactivity were determined. After infusion, the luminal and mucosal radioactive lipid content was analyzed. The results showed that there was significantly less lipid transported in the lymph of TS rats compared with TO rats. The results also showed a significant decrease in the absorption of TS as compared with TO. This was due in part to poor lipolysis. In addition, the lipid absorbed by the intestine of the TS rats was transported into lymph less efficiently than in TO rats.

  19. Quantitative NMR Analysis of Partially Substituted Biodiesel Glycerols

    SciTech Connect

    Nagy, M.; Alleman, T. L.; Dyer, T.; Ragauskas, A. J.

    2009-01-01

    Phosphitylation of hydroxyl groups in biodiesel samples with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane followed by 31P-NMR analysis provides a rapid quantitative analytical technique for the determination of substitution patterns on partially esterified glycerols. The unique 31P-NMR chemical shift data was established with a series mono and di-substituted fatty acid esters of glycerol and then utilized to characterize an industrial sample of partially processed biodiesel.

  20. Processes and systems for the production of propylene glycol from glycerol

    DOEpatents

    Frye, John G; Oberg, Aaron A; Zacher, Alan H

    2015-01-20

    Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.

  1. Value-added uses for crude glycerol--a byproduct of biodiesel production

    PubMed Central

    2012-01-01

    Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds. PMID:22413907

  2. Efficient synthetic protocols in glycerol under heterogeneous catalysis.

    PubMed

    Cravotto, Giancarlo; Orio, Laura; Gaudino, Emanuela Calcio; Martina, Katia; Tavor, Dorith; Wolfson, Adi

    2011-08-22

    The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents. PMID:21853535

  3. Key enzymes catalyzing glycerol to 1,3-propanediol.

    PubMed

    Jiang, Wei; Wang, Shizhen; Wang, Yuanpeng; Fang, Baishan

    2016-01-01

    Biodiesel can replace petroleum diesel as it is produced from animal fats and vegetable oils, and it produces about 10 % (w/w) glycerol, which is a promising new industrial microbial carbon, as a major by-product. One of the most potential applications of glycerol is its biotransformation to high value chemicals such as 1,3-propanediol (1,3-PD), dihydroxyacetone (DHA), succinic acid, etc., through microbial fermentation. Glycerol dehydratase, 1,3-propanediol dehydrogenase (1,3-propanediol-oxydoreductase), and glycerol dehydrogenase, which were encoded, respectively, by dhaB, dhaT, and dhaD and with DHA kinase are encompassed by the dha regulon, are the three key enzymes in glycerol bioconversion into 1,3-PD and DHA, and these are discussed in this review article. The summary of the main research direction of these three key enzyme and methods of glycerol bioconversion into 1,3-PD and DHA indicates their potential application in future enzymatic research and industrial production, especially in biodiesel industry. PMID:26966462

  4. Occurrence of glycerol uptake in Dunaliella tertiolecta under hyperosmotic stress.

    PubMed

    Lin, Huixin; Fang, Lei; Low, Chin Seng; Chow, Yvonne; Lee, Yuan Kun

    2013-02-01

    The unicellular halotolerant green alga species Dunaliella are able to proliferate in extremely varied salinities by synthesizing intracellular glycerol and adjusting the cell shape and volume. However, some marine Dunaliella species such as Dunaliella tertiolecta are not able to regulate cell volume as an immediate response to counter external osmotic shock. Here we report that a rapid shock-response mechanism is present in Dunaliella tertiolecta, involving uptake of exogenous glycerol in response to hyperosmotic shock without changing cell volume, and this glycerol uptake activity is associated with the Dunaliella tertiolecta glycerol uptake protein 1 (DtGUP1) gene, which belongs to the membrane-bound O-acyltransferase. The mutant DtGUP1-E, in which the DtGUP1 gene is silenced, displayed an inability to take up glycerol from the medium and showed cell death under hyperosmotic shock. To our knowledge, this is the first time a gene product has been reported in Dunaliella tertiolecta that is involved in glycerol uptake activity under hyperosmotic stress. PMID:23279806

  5. Microaerobic Conversion of Glycerol to Ethanol in Escherichia coli

    PubMed Central

    Wong, Matthew S.; Li, Mai; Black, Ryan W.; Le, Thao Q.; Puthli, Sharon; Campbell, Paul

    2014-01-01

    Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process. PMID:24584248

  6. Hydration and endocrine responses to intravenous fluid and oral glycerol.

    PubMed

    van Rosendal, S P; Strobel, N A; Osborne, M A; Fassett, R G; Coombes, J S

    2015-06-01

    Athletes use intravenous (IV) saline in an attempt to maximize rehydration. The diuresis from IV rehydration may be circumvented through the concomitant use of oral glycerol. We examined the effects of rehydrating with differing regimes of oral and IV fluid, with or without oral glycerol, on hydration, urine, and endocrine indices. Nine endurance-trained men were dehydrated by 4% bodyweight, then rehydrated with 150% of the fluid lost via four protocols: (a) oral = oral fluid only; (b) oral glycerol = oral fluid with added glycerol (1.5 g/kg); (c) IV = 50% IV fluid, 50% oral fluid; and (d) IV with oral glycerol = 50% IV fluid, 50% oral fluid with added glycerol (1.5 g/kg), using a randomized, crossover design. They then completed a cycling performance test. Plasma volume restoration was highest in IV with oral glycerol > IV > oral glycerol  > oral. Urine volume was reduced in both IV trials compared with oral. IV and IV with oral glycerol resulted in lower aldosterone levels during rehydration and performance, and lower cortisol levels during rehydration. IV with oral glycerol resulted in the greatest fluid retention. In summary, the IV conditions resulted in greater fluid retention compared with oral and lower levels of fluid regulatory and stress hormones compared with both oral conditions. PMID:25943662

  7. Importance of capillary perfusion.

    PubMed

    Hardaway, R M

    1979-11-01

    Perfusion is more critical than oxygen in the maintenance of cell viability. A high hematocrit or high fibrinogen level increases blood viscosity and predisposes to disseminated intravascular coagulation. It is recommended that a hematocrit of about 30 be maintained in periods of circulatory stress such as shock or extracorporeal circulation. PMID:495856

  8. Glycerol supplementation of the growth medium enhances in situ detoxification of furfural by Clostridium beijerinckii during butanol fermentation.

    PubMed

    Ujor, Victor; Agu, Chidozie Victor; Gopalan, Venkat; Ezeji, Thaddeus Chukwuemeka

    2014-01-01

    Lignocellulose-derived microbial inhibitors such as furfural and 5-hydroxymethyl furfural adversely affect fermentation of lignocellulosic biomass hydrolysates to fuels and chemicals due to their toxicity on fermenting microbes. To harness the potential of lignocellulose as a cheap source of fermentable sugars, in situ detoxification of furfural and other lignocellulose-derived microbial inhibitors is essential. To enhance in situ detoxification and tolerance of furfural by Clostridium beijerinckii NCIMB 8052 during acetone-butanol-ethanol (ABE) fermentation, the effect of glycerol on NADH/NADPH generation and ABE production by furfural (4, 5, and 6 g/L)-challenged cultures was investigated in this study. In all instances, beneficial outcomes were observed. For example, the fermentation medium supplemented with glycerol and subjected to 5 g/L furfural elicited up to 1.8- and 3-fold increases, respectively, in NADH and NADPH levels in C. beijerinckii 8052 relative to the control culture. These critical changes are the likely underpinnings for the glycerol-mediated 2.3-fold increase in the rate of detoxification of 5 g/L furfural, substrate consumption, and ABE production compared to the unsupplemented medium. Collectively, these results demonstrate that increased intracellular NADH/NADPH in C. beijerinckii 8052 due to glycerol utilization engenders favorable effects on many aspects of cellular metabolism, including enhanced furfural reduction and increased ABE production. PMID:24839212

  9. Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent.

    PubMed

    Seligra, Paula González; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-03-15

    Biodegradable and non-retrogradable starch-glycerol based films were obtained using citric acid (CA) as crosslinking agent at 75°C. This material allowed decreasing water vapor permeability (WVP) more than 35%, remained amorphous for at least 45 days as a result of the network formed by the CA that avoided starch retrogradation and maintained the degradability in compost, occurring only six days after the films without citric acid. A simulation of the gelatinization process of starch-glycerol with and without CA, using a differential thermal analysis device, showed that the system with CA completed the gelatinization 5°C before than the other and, CA first reacted with glycerol and then starch-glycerol-CA reaction occurred. The temperature at which the gelatinization process was carried out was critical to obtain the best results. An increase of gelatinization process temperature at 85°C in system with CA, led to a worsening on WVP and its integrity after a swelling process with dimethylsulphoxide (DMSO), compared to the films processed at 75°C. PMID:26794739

  10. Capillary Pressure of a Liquid Between Uniform Spheres Arranged in a Square-Packed Layer

    NASA Technical Reports Server (NTRS)

    Alexader, J. Iwan D.; Slobozhanin, Lev A.; Collicott, Steven H.

    2004-01-01

    The capillary pressure in the pores defined by equidimensional close-packed spheres is analyzed numerically. In the absence of gravity the menisci shapes are constructed using Surface Evolver code. This permits calculation the free surface mean curvature and hence the capillary pressure. The dependences of capillary pressure on the liquid volume constructed here for a set of contact angles allow one to determine the evolution of basic capillary characteristics under quasi-static infiltration and drainage. The maximum pressure difference between liquid and gas required for a meniscus passing through a pore is calculated and compared with that for hexagonal packing and with approximate solution given by Mason and Morrow [l]. The lower and upper critical liquid volumes that determine the stability limits for the equilibrium capillary liquid in contact with square packed array of spheres are tabulated for a set of contact angles.

  11. The Effect of Ion Motion on Laser-Driven Plasma Wake in Capillary

    NASA Astrophysics Data System (ADS)

    Zhou, Suyun; Chen, Hui; Li, Yanfang

    2016-01-01

    The effect of ion motion in capillary-guided laser-driven plasma wake is investigated through rebuilding a two-dimensional analytical model. It is shown that laser pulse with the same power can excite more intense wakefield in the capillary of a smaller radius. When laser intensity exceeds a critical value, the effect of ion motion reducing the wakefield rises, which becomes significant with a decrease of capillary radius. This phenomenon can be attributed to plasma ions in smaller capillary obtaining more energy from the plasma wake. The dependence of the difference value between maximal scalar potential of wake for two cases of ion rest and ion motion on the radius of the capillary is discussed. supported by National Natural Science Foundation of China (No. 11247016), the Natural Science Foundation of Jiangxi Province, China (Nos. 2014ZBAB202001 and 20151BAB212010), and the Science Foundation for Youths of the Jiangxi Education Committee of China (No. GJJ14224)

  12. Paramecium swimming in capillary tube

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

    2012-04-01

    Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

  13. Non-Aqueous Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Szumski, Michał; Buszewski, Bogusław

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

  14. Sounding rocket experiment on capillary channel flow

    NASA Astrophysics Data System (ADS)

    Rosendahl, U.; Fechtmann, C.; Dreyer, M. E.

    2005-08-01

    This paper is concerned with flow rate limitations in open capillary channels under low-gravity conditions. The channels consist of two parallel plates bounded by free liquid surfaces along the open sides. In the case of steady flow the capillary pressure of the free surface balances the differential pressure between the liquid and the surrounding constant-pressure gas phase. A maximum flow rate is achieved when the adjusted volumetric flow rate exceeds a certain limit leading to a collapse of the free surfaces. In order to investigate this type of flow an experiment aboard the sounding rocket TEXUS-41 was performed. The aim of the investigation was to achieve the profiles of the free liquid surfaces and to determine the maximum flow rate of the steady flow. For this purpose a new approach to the critical flow condition by enlarging the channel length was applied. The paper gives a review of the experimental set-up and the preparation of the flight procedures. Furthermore the experiment performance is described and the typical appearance of the flow indicated by its surface profiles is presented.

  15. Capillary interactions in Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Guzowski, J.; Tasinkevych, M.; Dietrich, S.

    2011-09-01

    The effective capillary interaction potentials for small colloidal particles trapped at the surface of liquid droplets are calculated analytically. Pair potentials between capillary monopoles and dipoles, corresponding to particles floating on a droplet with a fixed center of mass and subjected to external forces and torques, respectively, exhibit a repulsion at large angular separations and an attraction at smaller separations, with the latter resembling the typical behavior for flat interfaces. This change of character is not observed for quadrupoles, corresponding to free particles on a mechanically isolated droplet. The analytical results are compared with the numerical minimization of the surface free energy of the droplet in the presence of spherical or ellipsoidal particles.

  16. Nonsteady Flow in Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Hara, Ayako

    2000-03-01

    Surface phenomena in the field of electron devices and the problem of how long. It takes plants to absorb water during their growth in hydroponic cultivation is attraching the attention of riseachers. However, the related study of non-steady flow in capillary tubes has a number of issues that require investigation. In response to this situation, we made attempted to assess nonsteady fiow in capillary tubes, the liquid rise time and other issues, using a motion equation that takes factors including the friction force of the tube and the surface tension into consideration.

  17. Thermal-solutal capillary-buoyancy flow of a low Prandtl number binary mixture with a -1 capillary ratio in an annular pool

    NASA Astrophysics Data System (ADS)

    Yu, Jia-Jia; Wu, Chun-Mei; Li, You-Rong; Chen, Jie-Chao

    2016-08-01

    A series of three-dimensional numerical simulations on thermal-solutal capillary-buoyancy flow in an annular pool were carried out. The pool was filled with silicon-germanium melt with an initial silicon mass fraction of 1.99%. The Prandtl number and the Lewis number of the working fluid are 6.37 × 10-3 and 2197.8, respectively. Both the radial temperature gradient and the solute concentration gradient were applied to the annular pool. The capillary ratio was assumed to be -1, which means that the solutal and thermal capillary effects were equal and opposite. Results show that the thermal-solutal capillary-buoyancy flow always occurs at this special case with the capillary ratio of -1, and even in a shallow annular pool with an aspect ratio of 0.05. With the increase of the thermal Marangoni number, four kinds of flow patterns appear orderly, including concentric rolls, petal-like, spoke, and rosebud-like patterns. These flow patterns are strongly influenced by the local interaction between the solutal and thermal capillary effects and the vertical solute concentration gradient near the outer cylinder. A small vortex driven by the dominant solutal capillary effect emerges near the inner cylinder, which is different from the flow pattern in a pure fluid. In addition, the critical thermal Marangoni number of the initial three-dimensional flow decreases with the increase of the aspect ratio of the annular pool.

  18. Crude glycerol-based production of amino acids and putrescine by Corynebacterium glutamicum.

    PubMed

    Meiswinkel, Tobias M; Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2013-10-01

    Corynebacterium glutamicum possesses genes for glycerol kinase and glycerol-3-phosphate dehydrogenase that were shown to support slow growth with glycerol only when overexpressed from a plasmid. Pure glycerol and crude glycerol from biodiesel factories were tested for growth of recombinant strains expressing glpF, glpK and glpD from Escherichia coli. Some, but not all crude glycerol lots served as good carbon sources. Although the inhibitory compound(s) present in these crude glycerol lots remained unknown, the addition of substoichiometric glucose concentrations (below 10% by weight) enabled the utilization of some of the inhibitory crude glycerol lots. Besides growth, production of the amino acids L-glutamate, L-lysine, L-ornithine and L-arginine as well as of the diamine putrescine based on crude glycerol qualities from biodiesel factories was demonstrated. PMID:23562176

  19. Engineering of a glycerol utilization pathway for amino acid production by Corynebacterium glutamicum.

    PubMed

    Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2008-10-01

    The amino acid-producing organism Corynebacterium glutamicum cannot utilize glycerol, a stoichiometric by-product of biodiesel production. By heterologous expression of Escherichia coli glycerol utilization genes, C. glutamicum was engineered to grow on glycerol. While expression of the E. coli genes for glycerol kinase (glpK) and glycerol 3-phosphate dehydrogenase (glpD) was sufficient for growth on glycerol as the sole carbon and energy source, additional expression of the aquaglyceroporin gene glpF from E. coli increased growth rate and biomass formation. Glutamate production from glycerol was enabled by plasmid-borne expression of E. coli glpF, glpK, and glpD in C. glutamicum wild type. In addition, a lysine-producing C. glutamicum strain expressing E. coli glpF, glpK, and glpD was able to produce lysine from glycerol as the sole carbon substrate as well as from glycerol-glucose mixtures. PMID:18757581

  20. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1994-06-28

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

  1. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John A.

    1996-03-12

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

  2. 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.

  3. 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.

  4. Critical care in Nicaragua.

    PubMed

    Simko, L C

    1997-08-01

    Critical care nursing in Nicaragua is vastly different than critical care practiced in the United States. The current status of critical care nursing in Nicaragua is challenging at best. Medical personnel do not have access to arterial blood gases, blood cultures, and capillary blood glucose monitoring. The strengths and challenges present in Nicaraguan critical care has made the nursing staff rely on keen and astute nursing assessment of their patients. Due to the lack of technology in Nicaragua, creativity and improvising are a must in caring for a critically ill patient. However, the concerns and issues facing the nurses in Nicaragua are very similar to those experienced by critical care nurses in the United States. Critical care nursing in Nicaragua is indeed true nursing at its finest. PMID:9313419

  5. Percolation and Burgers' dynamics in a model of capillary formation

    NASA Astrophysics Data System (ADS)

    Coniglio, A.; de Candia, A.; di Talia, S.; Gamba, A.

    2004-05-01

    Capillary networks are essential in vertebrates to supply tissues with nutrients. Experiments of in vitro capillary formation show that cells randomly spread on a gel matrix autonomously organize to form vascular networks. Cells form disconnected networks at low densities and connected ones above a critical density. Above the critical density the network is characterized by a typical mesh size ˜200 μm , which is approximately constant on a wide range of density values. In this paper we present a full characterization of a recently proposed model which reproduces the main features of the biological system, focusing on its dynamical properties, on the fractal properties of patterns, and on the percolative phase transition. We discuss the relevance of the model in relation with some experiments in living beings and proposed diagnostic methods based on the measurement of the fractal dimension of vascular networks.

  6. Droplet motion driven by electro-elasto-capillary effects

    NASA Astrophysics Data System (ADS)

    Shah, Jaymeen; Yang, Xin; Sun, Ying

    2013-11-01

    The motion of droplets on natural and synthetic fibers underlines many technological applications including flexible displays, insulation, and smart filters. However, there is a lack of fundamental understanding of the coupled electrical, elastic, and capillary forces on droplets in fiber networks. In the present study, the motion of a water droplet suspended between two electrically insulated fibers of different Young's modulus, lengths and diameters are examined under electric fields. The results on rigid fibers reveal a critical voltage, under which the droplet remain stationary. Above this critical voltage, droplet self-propulsion is observed as a result of the interplay of electro, elasto and capillary forces on the droplet. The effects of the inter-fiber distance and Young's modulus on droplet motion are also discussed. The controllable motion of droplets can be used to manipulate or transport liquid at small scales.

  7. Glycerol dehydrates oedematous as well as normal brain in dogs.

    PubMed

    Wang, J Y; Chen, J L

    1994-04-01

    1. Although the effect of glycerol on reducing intracranial pressure has been widely investigated, only a few studies have reported its dehydrating effect on brain oedema caused by infarction, ischaemia, microembolism and cold injury, but none on traumatic oedema. In this study the effects of glycerol (1 g/kg, i.v. bolus infusion at a rate of 0.04 g/kg per min) on traumatic and cryogenic cerebral oedema and on normal brain were compared in the anaesthetized dog. The tissue water content was measured with the gravimetric method. 2. Oedema resulting from mechanical trauma was initiated 4 h prior to treatment with glycerol (8 dogs) or vehicle (5 dogs) by closed head contusion with fixed force under general anaesthesia. Tissue samples underneath the region of contusion were taken, before and 1 h after infusion of glycerol or vehicle, for the measurement of water content. 3. Glycerol infusion decreased the water content in white matter of the traumatic brain model from 76.54 +/- 1.70% to 70.73 +/- 1.54% (P < 0.001). In normal brain the reduction was from 68.42 +/- 0.48% to 65.36 +/- 0.39% (P < 0.001). Neither vehicle nor glycerol infusion resulted in significant changes in specific gravity of the gray matter. 4. Cryogenic oedema was initiated 3 h prior to the infusion of glycerol or vehicle by applying unilaterally a brass conical cup (bottom diameter 1 cm) filled with dry ice-acetone (-65 degrees C) to the exposed dura for 1 min. The contralateral hemisphere, which was not subjected to cold injury, was used for determination of water content of normal gray and white matter. 5. Glycerol infusion decreased the water content in the white matter of the cold-injured region from 75.38 +/- 0.69% to 72.57 +/- 0.58% (P < 0.001). In the normal white matter the reduction was from 68.63 +/- 0.34% to 65.48 +/- 0.49% (P < 0.001). 6. Our data indicate that glycerol decreases water content of the white matter in traumatic and cold-injured oedematous brain as well as in normal brain

  8. Capillary electrophoresis for drug analysis

    NASA Astrophysics Data System (ADS)

    Lurie, Ira S.

    1999-02-01

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

  9. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  10. Dysferlin and Myoferlin Regulate Transverse Tubule Formation and Glycerol Sensitivity

    PubMed Central

    Demonbreun, Alexis R.; Rossi, Ann E.; Alvarez, Manuel G.; Swanson, Kaitlin E.; Deveaux, H. Kieran; Earley, Judy U.; Hadhazy, Michele; Vohra, Ravneet; Walter, Glenn A.; Pytel, Peter; McNally, Elizabeth M.

    2015-01-01

    Dysferlin is a membrane-associated protein implicated in muscular dystrophy and vesicle movement and function in muscles. The precise role of dysferlin has been debated, partly because of the mild phenotype in dysferlin-null mice (Dysf). We bred Dysf mice to mice lacking myoferlin (MKO) to generate mice lacking both myoferlin and dysferlin (FER). FER animals displayed progressive muscle damage with myofiber necrosis, internalized nuclei, and, at older ages, chronic remodeling and increasing creatine kinase levels. These changes were most prominent in proximal limb and trunk muscles and were more severe than in Dysf mice. Consistently, FER animals had reduced ad libitum activity. Ultrastructural studies uncovered progressive dilation of the sarcoplasmic reticulum and ectopic and misaligned transverse tubules in FER skeletal muscle. FER muscle, and Dysf- and MKO-null muscle, exuded lipid, and serum glycerol levels were elevated in FER and Dysf mice. Glycerol injection into muscle is known to induce myopathy, and glycerol exposure promotes detachment of transverse tubules from the sarcoplasmic reticulum. Dysf, MKO, and FER muscles were highly susceptible to glycerol exposure in vitro, demonstrating a dysfunctional sarcotubule system, and in vivo glycerol exposure induced severe muscular dystrophy, especially in FER muscle. Together, these findings demonstrate the importance of dysferlin and myoferlin for transverse tubule function and in the genesis of muscular dystrophy. PMID:24177035

  11. Glycerol use in hyperhydration and rehydration: scientific update.

    PubMed

    van Rosendal, S P; Coombes, J S

    2012-01-01

    Glycerol ingestion creates an osmotic drive that enhances fluid retention. The major practical applications for athletes are to either (i) hyperhydrate before exercise so that they have more fluid to be lost as sweat during subsequent performance, thereby delaying the progression of dehydration from becoming physiologically significant, or (ii) improve both the rate of rehydration and total fluid retention following exercise. Recently we showed that rehydration may be improved further by combining glycerol with intravenous fluids. Improvements in endurance time, time trial performance and total power and work output have been seen during exercise following glycerol-induced hyperhydration or rehydration. Another recent trial showed that the increased body weight associated with the extra fluid does not inadvertently affect running economy. Concerns that the haemodilution associated with the fluid retention in the vascular space may be sufficient to mask illegal doping practices by athletes led the World Anti-Doping Agency (WADA) to add glycerol to its list of prohibited substances in 2010. Recent evidence suggests that doses of > 0.032 ± 0.010 g/kg lean body mass (much lower than those required for rehydration) will result in urinary excretion that may be detectable, so athletes under the WADA jurisdiction should be cautious to limit their inadvertent glycerol intake. PMID:23075560

  12. Treatment of glycerol phase formed by biodiesel production.

    PubMed

    Hájek, Martin; Skopal, Frantisek

    2010-05-01

    Glycerol is a by-product of biodiesel produced by transesterification and is contained in the glycerol phase together with many other materials such as soaps, remaining catalyst, water, and esters formed during the process. The content of glycerol is approximately 30-60 wt.%. In this paper, treatments of the glycerol phase to obtain glycerol with a purity of 86 wt.% (without distillation) and a mixture of fatty acids with esters (1:1) or only a mixture of fatty acids with a purity of 99 wt.% are presented. The treatment was carried out by removing of alkaline substances and esters. Fatty acids were produced by saponification of the remaining esters and subsequent neutralization of alkaline substances by phosphoric, sulfuric, hydrochloric, or acetic acids. Salts are by-products and, in the case of phosphoric acid can be used as potash-phosphate fertilizer. The process of treatment is easy and environmentally friendly, because no special chemicals or equipment are required and all products are utilizable. PMID:20074939

  13. Thermodynamics of interdigitated phases of phosphatidylcholine in glycerol.

    PubMed Central

    Swamy, M J; Marsh, D

    1995-01-01

    Comparison of the electron spin resonance spectra of phosphatidylcholines spin-labeled in the sn-2 chain at a position close to the polar region and close to the methyl terminus indicate that symmetrical saturated diacyl phosphatidylcholines with odd and even chain lengths from 13 to 20 C-atoms (and probably also 12 C-atoms) have gel phases in which the chains are interdigitated when dispersed in glycerol. The chain-length dependences of the chain-melting transition enthalpies and entropies are similar for phosphatidylcholines dispersed in glycerol and in water, but the negative end contributions are smaller for phosphatidylcholines dispersed in glycerol than for those dispersed in water: d delta Ht/dCH2 = 1.48 (1.43) kcal.mol-1, d delta St/dCH2 = 3.9 (4.0) cal.mol-1K-1, and delta H o = -12.9 (-15.0) kcal.mol-1, delta S o = -29 (-40) cal.mol-1K-1, respectively, for dispersions in glycerol (water). These differences reflect the interfacial energetics in glycerol and in water, and the different structure of the interdigitated gel phase. PMID:8534810

  14. Determination of optimal glycerol concentration for optical tissue clearing

    NASA Astrophysics Data System (ADS)

    Youn, Eungjun; Son, Taeyoon; Kim, Han-Sung; Jung, Byungjo

    2012-02-01

    The laser scattering in tissue is significant in diagnostic and therapeutic purposes of laser. Many studies have been conducted to minimize laser scattering in tissue and therefore, to maximize the clinical efficacy by enhancing photon density. Optical clearing agents (OCAs) have been employed for optical tissue clearing (OTC). This study was aimed to investigate the optimal concentration of an OCA, glycerol, in topical application,, so that it can be utilized for clinical diagnosis and therapy in dermatology. Glycerol was topically applied to avoid possible edema caused by dermal injection. The effect of OTC was quantitatively evaluated as a function of the concentration of glycerol with various methods. Optical methods such as optical coherence tomography (OCT) and an integrating sphere were used to assess the enhancement of light penetration depth and refractive index matching. In addition, a non-optical method, ultrasound scanner, was utilized to evaluate quantitatively collagen dissociation. The results revealed that 70 % glycerol was the optimal concentration of OTC for topical application. This study may provide a guideline regarding to the use of glycerol for optimal diagnostic and therapeutic effects in dermatology.

  15. The structure of GlpF, a glycerol conducting channel.

    PubMed

    Fu, Dax; Libson, Andrew; Stroud, Robert

    2002-01-01

    The passage of water or small neutral solutes across the cell membrane in animals, plants and bacteria is facilitated by a family of homologous membrane channels, variously known as aquaporins though perhaps more correctly as aquaglyceroporins. The glycerol facilitator (GlpF) is a 28 kDa aquaglyceroporin that catalyses transmembrane diffusion of glycerol and certain linear polyhydric alcohols in Escherichia coli. X-ray crystallographic analysis of GlpF to 2.2 A resolution revealed an alpha-barrel structure, surrounded by six full-length transmembrane helices and two half-spanning helices that are joined head-to-head in the middle of the membrane. These helices are arranged to a quasi twofold manner relative to the central membrane plane, where highly conserved residues make helix-to-helix contacts that stabilize the relative position and orientation of the helices in the structure. This sequence-structure correlation suggests that the evolutionary divergence of aquaporins and aquaglyceroporins is constrained by a conserved structural framework within which specialized function may be developed. Three glycerol molecules were resolved in the central channel through the GlpF monomer, thereby defining a transmembrane channel for glycerol permeation. The structure of glycerol GlpF complex provides insight into the chemical basis for transmembrane selective permeability. PMID:12027015

  16. Synthesis of monophytanyl ether analogues of lysophosphatidic and lysophosphatidyl glycerol.

    PubMed

    Kates, M; Hancock, A J

    1976-10-01

    The chemical synthesis of 3-O-phytanyl-sn-glycero-1-phosphoric acid (monophytanyl ether analogue of lysophosphatidic acid) was effected by condensation of 1-iodo-2-O-benzyl-3-O-phytanyl-sn-glycerol with silver di-p-nitrobenzyl phosphate in anhydrous toluene followed by catalytic hydrogenolysis of the resulting phosphotriester to remove the benzyl and p-nitrobenzyl groups. Synthesis of 3-O-phytanyl-sn-glycero-1-phosphoryl-1'-sn-glycerol (monophytanyl ether analogue of lysophosphatidyl glycerol) was carried out by conversion of the above phosphotriester to the monosilver salt of the suitably blocked lysophosphatidic acid which was condensed with 1-iodo-2-O-t-butyl-3-O-benzyl-sn-glycerol. Removal of the protecting aromatic and t-butyl groups from the resulting blocked triester intermediate gave the desired phytanyl ether analogue of lysophosphatidyl glycerol. Both lyso analogues were isolated as analytically and chromatographically pure potassium salts. Their physical properties and behavior towards acid hydrolysis are described. PMID:991376

  17. Callibration of capillaries for density measurement of supercooled water

    NASA Astrophysics Data System (ADS)

    Peukert, Pavel; Duška, Michal; Hykl, Jiří; Sladký, Petr; Nikl, Zbyněk; Hrubý, Jan

    2015-05-01

    Density of supercooled water at elevated pressure is interesting because of the strong anomalies which can be explained by existence of a liquid-liquid critical point in the region of supercooled water. In order to provide accurate data for density at these conditions a procedure was developed to calibrate the course of the inner cross section of a capillary along its length. Further, the image analysis for the sub-pixel evaluation of meniscus postion is described.

  18. Effect of NaCl on the accumulation of glycerol by three Aspergillus species.

    PubMed

    Zidan, M A; Abdel-Mallek, A Y

    1987-01-01

    The accumulation of glycerol was investigated in three Aspergillus species, A. niger, A. ochraceus and A. tamarii after being grown in media containing different NaCl concentrations. Intra-extracellular as well as total glycerol were markedly accumulated by the three organisms in response to increased salinity. However, at salinity levels of 10-14% NaCl, extracellular glycerol was somewhat lowered. In addition, it was found that the maximum accumulation of glycerol in A. niger and A. tamarii was reached within the first 10 hours after salinization. However, after desalinization, the extracellular glycerol was continuously increased within the first 6 hours at the expense of intracellular glycerol. PMID:3449615

  19. Gradient elution in capillary electrochromatography

    SciTech Connect

    Anex, D.; Rakestraw, D.J.; Yan, Chao; Dadoo, R.; Zare, R.N.

    1997-08-01

    In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

  20. Water availability determines branched glycerol dialkyl glycerol tetraether distributions in soils of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Menges, J.; Huguet, C.; Alcañiz, J. M.; Fietz, S.; Sachse, D.; Rosell-Melé, A.

    2013-06-01

    The MBT/CBT has recently gained significant attention as a novel paleotemperature proxy. It is based on the distribution of branched glycerol dialkyl glycerol tetraethers (GDGTs) in soils. The CBT quantifies the degree of cyclisation and relates to soil pH. The MBT' quantifies the degree of methylation and relates to mean annual temperature and soil pH. Combining these two indices allows estimation of mean annual temperature (MAT). However other factors such as soil water availability or moisture conditions have been suggested to influence the MBT'. To assess the effect of moisture conditions on the MBT'/CBT a set of 23 Iberian Peninsula soil samples covering a temperature range from 10-18 °C and a wide range of soil moisture regimes (405 mm to 1455 mm mean annual precipitation per year), was analyzed. We find that CBT is significantly correlated to soil pH confirming it as a robust proxy. In contrast the MBT' index was not correlated to MAT and was weakly correlated to annual mean precipitation (MAP). Instead we found a significant correlation between MBT' and the Aridity Index (AI), a parameter related to water availability in soils. The AI can explain 70% of the residuals of MAT estimation and 50% of the actual variation of the MBT'. This suggests that in dry environments or under moisture shortage the degree of methylation of branched GDGTs is not controlled by temperature but rather by the degree of water available. Our results suggest that the MBT/CBT index is not applicable as a paleotemperature proxy in dry subhumid to hyperarid environments.

  1. In situ production of branched glycerol dialkyl glycerol tetraethers in a great basin hot spring (USA)

    PubMed Central

    Zhang, Chuanlun L.; Wang, Jinxiang; Dodsworth, Jeremy A.; Williams, Amanda J.; Zhu, Chun; Hinrichs, Kai-Uwe; Zheng, Fengfeng; Hedlund, Brian P.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are predominantly found in soils and peat bogs. In this study, we analyzed core (C)-bGDGTs after hydrolysis of polar fractions using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry and analyzed intact P-bGDGTs using total lipid extract (TLE) without hydrolysis by liquid chromatography-electrospray ionization-multiple stage mass spectrometry. Our results show multiple lines of evidence for the production of bGDGTs in sediments and cellulolytic enrichments in a hot spring (62–86°C) in the Great Basin (USA). First, in situ cellulolytic enrichment led to an increase in the relative abundance of hydrolysis-derived P-bGDGTs over their C-bGDGT counterparts. Second, the hydrolysis-derived P- and C-bGDGT profiles in the hot spring were different from those of the surrounding soil samples; in particular, a monoglycosidic bGDGT Ib containing 13,16-dimethyloctacosane and one cyclopentane moiety was detected in the TLE but it was undetectable in surrounding soil samples even after sample enrichments. Third, previously published 16S rRNA gene pyrotag analysis from the same lignocellulose samples demonstrated the enrichment of thermophiles, rather than mesophiles, and total bGDGT abundance in cellulolytic enrichments correlated with the relative abundance of 16S rRNA gene pyrotags from thermophilic bacteria in the phyla Bacteroidetes, Dictyoglomi, EM3, and OP9 (“Atribacteria”). These observations conclusively demonstrate the production of bGDGTs in this hot spring; however, the identity of organisms that produce bGDGTs in the geothermal environment remains unclear. PMID:23847605

  2. Accelerated dynamics of supercooled glycerol in soft confinement

    NASA Astrophysics Data System (ADS)

    Blochowicz, T.; Gouirand, E.; Fricke, A.; Spehr, T.; Stühn, B.; Frick, B.

    2009-06-01

    We investigate the dynamics of supercooled glycerol in a soft confinement within microemulsion droplets. The structure of the system is characterized by small-angle neutron scattering. We show that temperature-stable droplets establish a confinement, which may be varied in size from about 1 to 10 nm. Subsequently we focus on the dynamics of glass-forming glycerol confined within nanodroplets of different sizes. By combining neutron backscattering and time-of-flight for a broad dynamic range we obtain the incoherent intermediate scattering function S(q,t), which reveals increasingly accelerated dynamics as glycerol is confined to smaller droplets and for the relaxation times a crossover from Vogel-Fulcher behavior in the bulk to an Arrhenius law in confinement.

  3. Ru/FTO: Heterogeneous catalyst for glycerol hydrogenolysis

    NASA Astrophysics Data System (ADS)

    Samad, Wan Zurina; Isahak, Wan Nor Roslam Wan; Liew, Kin Hong; Nordin, Norazzizi; Yarmo, Mohd Ambar; Yusop, Muhammad Rahimi

    2014-09-01

    An introduction of Fluorine-doped tin oxide (FTO) as new catalyst support with Ru metal had enhanced the conversion and selectivity for glycerol hydrogenolysis. A small cluster of Ru were highly dispersed and intercalated over FTO via simple chemical mixture and reduction method. In comparison with various metal (Pd, Os, Cu), Ru/FTO catalyst showed the highest conversion (100%) and highly selectivity of 1,2-propanediol (94%) in the hydrogenolysis of glycerol. The reaction was optimally conducted at 150 °C, 20 bar of H2 pressure and at 8 hours. Ru/FTO catalyst was ascribed as active catalyst due to the amphoteric sites of FTO and small size of Ru metal. This provides high surface concentration of reduction process that involves the chemical bond dissociation in the glycerol hydrogenolysis.

  4. Enhanced production of 3-hydroxypropionic acid from glycerol by modulation of glycerol metabolism in recombinant Escherichia coli.

    PubMed

    Kim, Kwangwook; Kim, Sun-Ki; Park, Yong-Cheol; Seo, Jin-Ho

    2014-03-01

    3-Hydroxypropionic acid (3-HP) is a valuable biochemical with high potential for bioplastic manufacturing. The endogenous glycerol metabolism and by-product formation pathway in Escherichia coli were modulated to enhance 3-HP production from glycerol. Double deletion of glpK and yqhD directed the glycerol flux to 3-HP biosynthesis and reduced the formation of 1,3-propanediol. Since 3-hydroxypropionaldehyde (3-HPA), a precursor of 3-HP, is toxic to cell growth, the gene encoding Pseudomonas aeruginosa semialdehyde dehydrogenase (PSALDH) highly active on 3-HPA was expressed in E. coli. Finally, fed-batch culture of recombinant E. coli BL21star(DE3) without glpK and yqhD, and expressing Lactobacillus brevis DhaB-DhaR, and P. aeruginosa PSALDH resulted in 57.3g/L 3-HP concentration, 1.59g/L-h productivity and 0.88g/g yield. In conclusion, modulation of the glycerol metabolism in combination with enhanced activity of 3-HPA dehydrogenation improved the production of 3-HP from glycerol. PMID:24502915

  5. A study of heat flux induced dryout in capillary grooves

    NASA Astrophysics Data System (ADS)

    Murphy, Timothy J.

    1992-12-01

    This is an experimental study of ethanol flowing in the narrow grooves of a copper plate which is subjected to heat fluxes sufficient to evaporate more liquid than can be replaced by capillary pumping. Three groove geometries are used: square, rectangle, and trapezoid. The objective is to simulate aspects of liquid flow in heat pipes with axial grooves. In order to validate analytical models of capillary flow in grooves, the capillary limit, dryout front location, and dryout front movement in response to power draw downs are documented. The results show the rewet performance of the groove is dependent on geometry. Grooves of higher heat transfer capacity can be poor for recovering from dryout, like the trapezoidal groove. Comparisons of the theoretical maximum heat transfer with the data are good for the square and rectangle, but overestimate the value for the trapezoid. No theory sufficiently predicted the location of the dryout front for the three geometries. For both a quiescent dryout front and a boiling dryout front, the theory does not utilize an accurate description of the geometry of the liquid front which is critical for determining the capillary pressure difference.

  6. Capillary Flow in Containers of Polygonal Section: Theory and Experiment

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M.; Rame, Enrique (Technical Monitor)

    2001-01-01

    An improved understanding of the large-length-scale capillary flows arising in a low-gravity environment is critical to that engineering community concerned with the design and analysis of spacecraft fluids management systems. Because a significant portion of liquid behavior in spacecraft is capillary dominated it is natural to consider designs that best exploit the spontaneous character of such flows. In the present work, a recently verified asymptotic analysis is extended to approximate spontaneous capillary flows in a large class of cylindrical containers of irregular polygonal section experiencing a step reduction in gravitational acceleration. Drop tower tests are conducted using partially-filled irregular triangular containers for comparison with the theoretical predictions. The degree to which the experimental data agree with the theory is a testament to the robustness of the basic analytical assumption of predominantly parallel flow. As a result, the closed form analytical expressions presented serve as simple, accurate tools for predicting bulk flow characteristics essential to practical low-g system design and analysis. Equations for predicting corner wetting rates, total container flow rates, and transient surfaces shapes are provided that are relevant also to terrestrial applications such as capillary flow in porous media.

  7. Effect of biodiesel-derived raw glycerol on 1,3-propanediol production by different microorganisms.

    PubMed

    Moon, Chuloo; Ahn, Jae-Hyeong; Kim, Seung W; Sang, Byoung-In; Um, Youngsoon

    2010-05-01

    The microbial production of 1,3-propanediol (1,3-PD) from raw glycerol, a byproduct of biodiesel production, is economically and environmentally advantageous. Although direct use of raw glycerol without any pretreatment is desirable, previous studies have reported that this could cause inhibition of microbial growth. In this study, we investigated the effects of raw glycerol type, different microorganisms, and pretreatment of raw glycerol on the production of 1,3-PD. Raw glycerol from waste vegetable-oil-based biodiesel production generally caused more inhibition of 1,3-PD production and microbial growth compared to raw glycerol from soybean-oil-based biodiesel production. In addition, two raw glycerol types produced from two biodiesel manufacturers using waste vegetable oil exhibited different 1,3-PD production behavior, partially due to different amounts of methanol included in the raw glycerol from the two biodiesel manufacturers. Klebsiella strains were generally resistant to all types of raw glycerol while the growth of Clostridium strains was variably inhibited depending on the type of raw glycerol. The 1,3-PD production of the Clostridium strains using acid-pretreated raw glycerol was significantly enhanced compared to that with raw glycerol, demonstrating the feasibility of using raw glycerol for 1,3-PD production by various microorganisms. PMID:19937397

  8. Pulse loading of glycerol by electric explosion of wire

    NASA Astrophysics Data System (ADS)

    Uvarov, S. V.; Bannikova, I. A.; Naimark, O. B.

    2015-11-01

    A series of experiments was carried out to investigate the relaxation properties of glycerol under shock-wave loading. The strain rates at the compression wave front were in the range of 105-107 s-1. A modified version of the wire explosion set-up was used. Free surface velocity profiles were recorded by VISAR with fiber-optic sensor. We found that the glycerol exhibits the non-Newtonian liquid behavior: viscosity is higher at the high strain rate. Strain rate at the compressive wave front is found to be dependent on the wave amplitude in power of 1.3.

  9. Propylene from renewable resources: catalytic conversion of glycerol into propylene.

    PubMed

    Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

    2014-03-01

    Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene. PMID:24578188

  10. Cryoprotective effect of different glycerol concentrations on domestic cat spermatozoa.

    PubMed

    Villaverde, Ana Izabel S Balbin; Fioratti, Eduardo G; Penitenti, Marcimara; Ikoma, Maura R V; Tsunemi, Miriam H; Papa, Frederico O; Lopes, Maria D

    2013-10-15

    Cryopreservation of spermatozoa is a pivotal tool in assisted reproduction, and studies aiming to establish optimal freezing/thawing protocols are essential to enhance sperm survival. The objectives of the present study were to (1) compare the cryoprotective efficiency of three different glycerol concentrations (3%, 5%, and 7%) on the basis of post-thaw sperm quality and (2) investigate whether the incidence of morphologically abnormal sperm in fresh samples is related to cryodamage sensitivity. Semen was collected from six tomcats using an artificial vagina (total 18 ejaculates). Each ejaculate was diluted using Tris-egg yolk-based extender (TEY), evaluated, equally divided into three aliquots, and rediluted using TEY with and without glycerol to achieve final concentrations of 3%, 5%, and 7%. Samples were loaded into 0.25 mL straws, equilibrated for 60 minutes at 5 °C, frozen, and then thawed at 46 °C for 12 seconds. Fresh and frozen-thawed samples were evaluated for sperm motion parameters (computer-assisted sperm analysis), plasma membrane integrity (PMI; propidium iodide and carboxyfluorescein diacetate), and DNA integrity (acridine orange). Plasma and acrosomal membrane integrity were assessed by flow cytometry (propidium iodide and fluorescein isothiocyanate-conjugated pea (Pisum sativum) agglutinin) immediately after thawing. Sperm motion parameters were also evaluated at 30 and 60 minutes of postincubation. For all treatment groups, cryopreservation significantly impaired the PMI and sperm motion parameters, except for straightness and amplitude of lateral head displacement. DNA integrity showed a slight reduction (P < 0.05) when 3% glycerol was used. The percentage of total motility, progressive motility, and rapid spermatozoa were significantly lower immediately after thawing and up to 60 minutes of incubation for the 3% glycerol group when compared with 5% and 7%. No difference (P > 0.05) was found for PMI, acrosome integrity, and DNA integrity among

  11. Dielectric and specific heat relaxations in vapor deposited glycerol.

    PubMed

    Kasina, A; Putzeys, T; Wübbenhorst, M

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs

  12. Pore-scale study of capillary trapping mechanism during CO2 injection in geological formations

    SciTech Connect

    Bandara, Uditha C.; Tartakovsky, Alexandre M.; Palmer, Bruce J.

    2011-11-01

    Geological sequestration of CO{sub 2} gas emerged as a promising solution for reducing amount of green house gases in atmosphere. A number of continuum scale models are available to describe the transport phenomena of CO{sub 2} sequestration. These models rely heavily on a phenomenological description of subsurface transport phenomena and the predictions can be highly uncertain. Pore-scale models provide a better understanding of fluid displacement processes, nonetheless such models are rare. In this work we use a Smoothed Particle Hydrodynamics (SPH) model to study pore-scale displacement and capillary trapping mechanisms of super-critical CO{sub 2} in the subsurface. Simulations are carried out to investigate the effects of gravitational, viscous, and capillary forces in terms of Gravity, Capillary, and Bond numbers. Contrary to the other published continuum scale investigations, we found that not only Gravity number but also Capillary number plays an important role on the fate of injected CO{sub 2}. For large Gravity numbers (on the order of 10), most of the injected CO{sub 2} reaches the cap-rock due to gravity segregation. A significant portion of CO{sub 2} gets trapped by capillary forces when Gravity number is small (on the order of 0.1). When Gravity number is moderately high (on the order of 1), trapping patterns are heavily dependent on Capillary number. If Capillary number is very small (less than 0.001), then capillary forces dominate the buoyancy forces and a significant fraction of injected CO{sub 2} is trapped by the capillary forces. Conversely, if Capillary number is high (higher than 0.001), capillary trapping is relatively small since buoyancy dominates the capillary forces. In addition, our simulations reveal different types of capillary trapping and flow displacement mechanisms during and after injection. In gravity dominated cases leave behind was the widespread trapping mechanism. Division was the primary trapping mechanism in viscous

  13. Toward Atomistic Resolution Structure of Phosphatidylcholine Headgroup and Glycerol Backbone at Different Ambient Conditions.

    PubMed

    Botan, Alexandru; Favela-Rosales, Fernando; Fuchs, Patrick F J; Javanainen, Matti; Kanduč, Matej; Kulig, Waldemar; Lamberg, Antti; Loison, Claire; Lyubartsev, Alexander; Miettinen, Markus S; Monticelli, Luca; Määttä, Jukka; Ollila, O H Samuli; Retegan, Marius; Róg, Tomasz; Santuz, Hubert; Tynkkynen, Joona

    2015-12-10

    Phospholipids are essential building blocks of biological membranes. Despite a vast amount of very accurate experimental data, the atomistic resolution structures sampled by the glycerol backbone and choline headgroup in phoshatidylcholine bilayers are not known. Atomistic resolution molecular dynamics simulations have the potential to resolve the structures, and to give an arrestingly intuitive interpretation of the experimental data, but only if the simulations reproduce the data within experimental accuracy. In the present work, we simulated phosphatidylcholine (PC) lipid bilayers with 13 different atomistic models, and compared simulations with NMR experiments in terms of the highly structurally sensitive C-H bond vector order parameters. Focusing on the glycerol backbone and choline headgroups, we showed that the order parameter comparison can be used to judge the atomistic resolution structural accuracy of the models. Accurate models, in turn, allow molecular dynamics simulations to be used as an interpretation tool that translates these NMR data into a dynamic three-dimensional representation of biomolecules in biologically relevant conditions. In addition to lipid bilayers in fully hydrated conditions, we reviewed previous experimental data for dehydrated bilayers and cholesterol-containing bilayers, and interpreted them with simulations. Although none of the existing models reached experimental accuracy, by critically comparing them we were able to distill relevant chemical information: (1) increase of choline order parameters indicates the P-N vector tilting more parallel to the membrane, and (2) cholesterol induces only minor changes to the PC (glycerol backbone) structure. This work has been done as a fully open collaboration, using nmrlipids.blogspot.fi as a communication platform; all the scientific contributions were made publicly on this blog. During the open research process, the repository holding our simulation trajectories and files ( https

  14. Toward Atomistic Resolution Structure of Phosphatidylcholine Headgroup and Glycerol Backbone at Different Ambient Conditions†

    PubMed Central

    2015-01-01

    Phospholipids are essential building blocks of biological membranes. Despite a vast amount of very accurate experimental data, the atomistic resolution structures sampled by the glycerol backbone and choline headgroup in phoshatidylcholine bilayers are not known. Atomistic resolution molecular dynamics simulations have the potential to resolve the structures, and to give an arrestingly intuitive interpretation of the experimental data, but only if the simulations reproduce the data within experimental accuracy. In the present work, we simulated phosphatidylcholine (PC) lipid bilayers with 13 different atomistic models, and compared simulations with NMR experiments in terms of the highly structurally sensitive C–H bond vector order parameters. Focusing on the glycerol backbone and choline headgroups, we showed that the order parameter comparison can be used to judge the atomistic resolution structural accuracy of the models. Accurate models, in turn, allow molecular dynamics simulations to be used as an interpretation tool that translates these NMR data into a dynamic three-dimensional representation of biomolecules in biologically relevant conditions. In addition to lipid bilayers in fully hydrated conditions, we reviewed previous experimental data for dehydrated bilayers and cholesterol-containing bilayers, and interpreted them with simulations. Although none of the existing models reached experimental accuracy, by critically comparing them we were able to distill relevant chemical information: (1) increase of choline order parameters indicates the P–N vector tilting more parallel to the membrane, and (2) cholesterol induces only minor changes to the PC (glycerol backbone) structure. This work has been done as a fully open collaboration, using nmrlipids.blogspot.fi as a communication platform; all the scientific contributions were made publicly on this blog. During the open research process, the repository holding our simulation trajectories and files (https

  15. Glomerular hemodynamics in established glycerol-induced acute renal failure in the rat.

    PubMed Central

    Wolfert, A I; Oken, D E

    1989-01-01

    The glomerular dynamic correlates of failed filtration were studied in volume replete rats with established glycerol-induced acute renal failure (ARF). Over one-half of all nephrons formed virtually no filtrate, while the single nephron glomerular filtration rate (SNGFR) of fluid-filled nephrons, measured at the glomerulotubular junction to preclude the possibility of covert tubular leakage, averaged one-sixth of control (P less than 0.001). Even that low mean value was elevated by a few nephrons with a near normal SNGFR. Renal failure thus reflected both total filtration failure in the majority of nephrons and massively reduced filtration in most of the remainder. Glomerular capillary pressure (Pg) averaged some 14 mmHg below control (P less than 0.001), whereas the arterial colloid osmotic and Bowman's space pressures were not significantly altered. Renocortical and whole kidney blood flow were also unchanged. Marked internephron functional heterogeneity precluded estimates of the ultrafiltration coefficient. However, the fall in SNGFR correlated well with the markedly depressed Pg and afferent net filtration pressure (delta PnetA, P less than 0.001), which in turn were caused by increased preglomerular resistance and a reciprocal fall in efferent arteriolar resistance. This complex change in intrarenal resistances was largely, if not entirely, responsible for failed filtration in this ARF model. PMID:2592568

  16. Freeze resistance in rainbow smelt (Osmerus mordax): seasonal pattern of glycerol and antifreeze protein levels and liver enzyme activity associated with glycerol production.

    PubMed

    Lewis, Johanne M; Ewart, K Vanya; Driedzic, William R

    2004-01-01

    Rainbow smelt (Osmerus mordax) inhabit inshore waters along the North American Atlantic coast. During the winter, these waters are frequently ice covered and can reach temperatures as low as -1.9 degrees C. To prevent freezing, smelt accumulate high levels of glycerol, which lower the freezing point via colligative means, and antifreeze proteins (AFP). The up-regulation of the antifreeze response (both glycerol and AFP) occurs in early fall, when water temperatures are 5 degrees -6 degrees C. The accumulation of glycerol appears to be the main mechanism of freeze resistance in smelt because it contributes more to the lowering of the body's freezing point than the activity of the AFP (0.5 degrees C vs. 0.25 degrees C for glycerol and AFP, respectively) at a water temperature of -1.5 degrees C. Moreover, AFP in smelt appears to be a safeguard mechanism to prevent freezing when glycerol levels are low. Significant increases in activities of the liver enzymes glycerol 3-phosphate dehydrogenase (GPDH), alanine aminotransferase (AlaAT), and phosphoenolpyruvate carboxykinase (PEPCK) during the initiation of glycerol production and significant correlations between enzyme activities and plasma glycerol levels suggest that these enzymes are closely associated with the synthesis and maintenance of elevated glycerol levels for use as an antifreeze. These findings add further support to the concept that carbon for glycerol is derived from amino acids. PMID:15286915

  17. A single amino acid change in Escherichia coli glycerol kinase abolishes glucose control of glycerol utilization in vivo.

    PubMed

    Pettigrew, D W; Liu, W Z; Holmes, C; Meadow, N D; Roseman, S

    1996-05-01

    Escherichia coli glycerol kinase (EC 2.7.1.30; ATP:glycerol 3-phosphotransferase) is a key element in glucose control of glycerol metabolism. Its catalytic activity is inhibited allosterically by the glycolytic intermediate, fructose 1,6-biphosphate, and by the phosphotransferase system phosphocarrier protein, IIIGlc (also known as IIAGlc). These inhibitors provide mechanisms by which glucose blocks glycerol utilization in vivo. We report here the cloning and sequencing of the glpK22 gene isolated from E. C. C. Lin strain 43, a strain that shows the loss of glucose control of glycerol utilization. DNA sequencing shows a single missense mutation that translates to the amino acid change Gly-304 to Ser (G-304-S) in glycerol kinase. The effects of this substitution on the functional and physical properties of the purified mutant enzyme were determined. Neither of the allosteric ligands inhibits it under conditions that produce strong inhibition of the wild-type enzyme, which is sufficient to explain the phenotype of strain 43. However, IIIGlc activates the mutant enzyme, which could not be predicted from the phenotype. In the wild-type enzyme, G-304 is located 1.3 nm from the active site and 2.5 nm from the IIIGlc binding site (M. Feese, D. W. Pettigrew, N. D. Meadow, S. Roseman, and S. J. Remington, Proc. Natl. Acad. Sci. USA 91:3544-3548, 1994). It is located in the same region as amino acid substitutions in the related protein DnaK which alter its catalytic and regulatory properties and which are postulated to interfere with a domain closure motion (A. S. Kamath-Loeb, C. Z. Lu, W.-C. Suh, M. A. Lonetto, and C. A. Gross, J. Biol. Chem. 270:30051-30059, 1995). The global effect of the G-304-S substitution on the conformation and catalytic and regulatory properties of glycerol kinase is consistent with a role for the domain closure motion in the molecular mechanism for glucose control of glycerol utilization. PMID:8631672

  18. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    SciTech Connect

    Gupta, S.; Arend, N.; Lunkenheimer, P.; Loidl, A.; Stingaciu, L.; Jalarvo, N.; Mamontov, E.; Ohl, M.

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, which directly couples to density fluctuations.

  19. Capillary electrophoresis systems and methods

    DOEpatents

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

    2011-08-02

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

  20. Synthesis of isotopically labeled R- or S-[.sup.13C, .sup.2H] glycerols

    DOEpatents

    Martinez, Rodolfo A.; Unkefer, Clifford J.; Alvarez, Marc A.

    2008-01-22

    The present invention is directed to asymmetric chiral labeled glycerols including at least one chiral atom, from one to two .sup.13C atoms and from zero to four deuterium atoms bonded directly to a carbon atom, e.g., (2S) [1,2-.sup.13C.sub.2]glycerol and (2R) [1,2-.sup.13C.sub.2]glycerol, and to the use of such chiral glycerols in the preparation of labeled amino acids.

  1. Treelike networks accelerating capillary flow

    NASA Astrophysics Data System (ADS)

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006), 10.1103/PhysRevE.73.066302; J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007), 10.1103/PhysRevE.75.056301]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube.

  2. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

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

  3. Treelike networks accelerating capillary flow.

    PubMed

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006); J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007)]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube. PMID:25353880

  4. Viscous peeling with capillary suction

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Lister, John

    2014-11-01

    If an elastic tape is stuck to a rigid substrate by a thin film of viscous fluid and then peeled off by pulling at a small angle to the horizontal, then both viscous and capillary forces affect the peeling speed (McEwan and Taylor, 1966). If there is no capillary meniscus (e.g. if the peeling is due to viscous fluid being injected under the tape), then the peeling speed is given by a Cox-Voinov-like law, and is an increasing function of the peeling angle. We show that, with a meniscus present, the effect of the capillary forces is to suck down the tape, reducing the effective peeling angle and hence the peeling speed. When surface tension dominates and the peeling speed tends to zero, the system transitions to a new state whose time-evolution can be described by a system of coupled ordinary differential equations. These asymptotic results are confirmed by numerical calculations. Similar results hold for the peeling-by-bending of elastic beams, with ``angle'' replaced by ``curvature'' (i.e. bending moment).

  5. Seasonal variability of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in a temperate lake system

    NASA Astrophysics Data System (ADS)

    Loomis, Shannon E.; Russell, James M.; Heureux, Ana M.; D'Andrea, William J.; Sinninghe Damsté, Jaap S.

    2014-11-01

    Quantitative climate reconstructions are crucial for understanding the magnitude of and mechanisms behind natural and anthropogenic climate change, yet there are few proxies that can reliably reconstruct terrestrial temperature. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are increasingly used to reconstruct paleotemperature from lake sediments, but despite their potential, we have a poor understanding of (1) autochthonous vs. allochthonous sources of brGDGTs in lakes and (2) the seasonality of and environmental controls on brGDGT production within lakes. To investigate these factors, we examined water column suspended particulate matter (SPM) and settling particles from a sediment trap collected on a biweekly to monthly basis over a period of three years at Lower King Pond, a small kettle lake in northern Vermont, USA. We also compared the concentration and fractional abundances of brGDGTs in SPM and settling particles with those of catchment soils, river sediments, and lake surface sediments to constrain the relative importance of brGDGTs derived from the landscape versus brGDGTs produced within the lake itself. We find significant differences in concentrations and fractional abundances of brGDGTs between soil and river sediment samples from the catchment and lake sediments, indicating a mostly autochthonous source for lacustrine brGDGTs. BrGDGT concentrations, fluxes, and fractional abundances in SPM vary over the annual cycle, indicating that brGDGTs are produced throughout the year and respond to changes within the water column. The total annual flux of brGDGTs settling through the water column is comparable to the brGDGT accumulation rates in surface sediments, indicating that in this lake brGDGTs are mostly produced within the water column, not in the sediment itself. While brGDGTs are produced in all seasons within the water column, the flux to the sediments is highest during periods of spring and fall

  6. Progression of Diabetic Capillary Occlusion: A Model

    PubMed Central

    Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

    2016-01-01

    An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

  7. Fluid Delivery System For Capillary Electrophoretic Applications.

    DOEpatents

    Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

    2002-04-23

    An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

  8. Synthesis, characterization and nanocomposite formation of poly(glycerol succinate-co-maleate) with cellulose nanowhiskers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel biodegradable polymer based on glycerol, succinic anhydride and maleic anhydride, poly(glycerol succinate-co-maleate), poly(GlySAMA), was synthesized by melt polycondensation and tested as a matrix for composites with cellulose nanowhiskers. This glycerol-based polymer is thermally stable as...

  9. Efficient utilization of crude glycerol as fermentation substrate in the synthesis of poly(3-hydroxybutyrate) biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One refined and 2 crude glycerol samples were utilized to produce poly(3-hydroxybutyrate) (PHB) by Pseudomonas oleovorans NRRL B-14682. Fermentation conditions were determined to efficiently utilize glycerol while maintaining PHB yields. A batch culture protocol including 1% glycerol and an aerati...

  10. Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice.

    PubMed

    Hara, Mariko; Verkman, A S

    2003-06-10

    Mice deficient in the epidermal water/glycerol transporter aquaporin-3 (AQP3) have reduced stratum corneum (SC) hydration and skin elasticity, and impaired barrier recovery after SC removal. SC glycerol content is reduced 3-fold in AQP3 null mice, whereas SC structure, protein/lipid composition, and ion/osmolyte content are not changed. We show here that glycerol replacement corrects each of the defects in AQP3 null mice. SC water content, measured by skin conductance and 3H2O accumulation, was 3-fold lower in AQP3 null vs. wild-type mice, but became similar after topical or systemic administration of glycerol in quantities that normalized SC glycerol content. SC water content was not corrected by glycerol-like osmolytes such as xylitol, erythritol, and propanediol. Orally administered glycerol fully corrected the reduced skin elasticity in AQP3 null mice as measured by the kinetics of skin displacement after suction, and the delayed barrier recovery as measured by transepidermal water loss after tape-stripping. Analysis of [14C]glycerol kinetics indicated reduced blood-to-SC transport of glycerol in AQP3 null mice, resulting in slowed lipid biosynthesis. These data provide functional evidence for a physiological role of glycerol transport by an aquaglyceroporin, and indicate that glycerol is a major determinant of SC water retention, and mechanical and biosynthetic functions. Our findings establish a scientific basis for the >200-yr-old empirical practice of including glycerol in cosmetic and medicinal skin formulations. PMID:12771381

  11. Production of arabitol from glycerol: strain screening and study of factors affecting production yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is a major byproduct from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotole...

  12. The Effect of Glycerol Ingestion on Performance during Simulated Multisport Activity

    ERIC Educational Resources Information Center

    Knight, Christopher; Braakhuis, Andrea; Paton, Carl

    2010-01-01

    Glycerol-induced hyperhydration has been applied to endurance sport with limited success as a performance enhancement strategy. Glycerol has been used as a hyperhydrating agent, because it has been shown to be rapidly absorbed and osmotically active; therefore, the fluid intake with glycerol is distributed throughout the body. Hyperhydration with…

  13. Nitrogen-Corrected Apparent Metabolizable Energy Value of Crude Glycerol for Laying Hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was conducted with laying hens to determine the AMEn value of crude glycerol, a co-product of biodiesel production. Crude glycerol (87% glycerol, 9% water, 0.03% methanol, 1.26% Na, and 3,625 kcal/kg gross energy) was obtained from a commercial biodiesel production facility (Ag Process...

  14. Thermal and mechanical properties of glycerol-based polymer films infused with plant cell wall polysaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(glutaric acid-co-glycerol) films were produced by first synthesizing polymer gels from uncatalyzed polyesterification of glutaric acid to glycerol in toluene. Residual amounts of starting materials in the gel matrices were determined by gas chromatography (GC) to contain 15 percent glycerol and...

  15. Modelling the effect of pore structure and wetting angles on capillary rise in soils having different wettabilities

    NASA Astrophysics Data System (ADS)

    Czachor, Henryk

    2006-09-01

    SummaryCapillary rise in axis symmetrical sinusoidal capillary (SC) has been modelled. Analytical formula for meniscus radius, capillary pressure and meniscus rate in SC have been found. Capillary shape described by wall waviness highly influences all of them. The limit between wettability and repellency in such capillary is described by critical value of contact angle θc which is related to the pore geometry by the equation ctg( θc) = πd2, where d2 - pore wall waviness. Kinetics of capillary rise in sinusoidal capillary has been determined by numerical integration of meniscus rate equation for a wide range of pore wall waviness and several values of contact angles. Application of Washburn theory to the data obtained from simulation gives the contact angle value much higher than the true one. In contrast, the obtained pore radius value is usually well correlated with capillary neck. However, in some cases a calculated radius can be even smaller. Above conclusions have been qualitatively confirmed by experiments performed on glass beads and soils. Contact angle measured on flat glass was 27.4°. The calculations concerning the data from capillary rise experiments on 90-1000 μm fraction of glass powder and Washburn theory gave values ca. 80°. The contact angle values for peat soils and loamy sand have close values, which supports the opinion that non-cylindrical shape of soil pores highly influences both the wettability/repellency and the water flux in soils.

  16. Toxicity of palmitoyl glycerol to mice: depression of thyroid function

    SciTech Connect

    Trumbo, P.R.; Meuten, D.J.; King, M.W.; Tove, S.B.

    1987-10-01

    Mice given propylthiouracil, a thyroid inhibitor, and fed a diet containing a nontoxic level of rac-1(3)-palmitoyl glycerol showed the hypothermia and mortality expected for a toxic dose, but did not show these signs when linoleate or oleate was added to the diet. Loss of radioiodine from the whole animal and thyroid gland was slower when mice were fed the toxic palmitoyl glycerol diet than when fed the same diet containing 4% safflower oil. However, mice fed the two diets did not differ in the extent of the incorporation of radioiodine, and essentially all was bound to protein in each case. Follicular thyroid cells from mice fed the potentially toxic diet that contained unsaturated fat were normal in appearance. Conversely, cells from mice fed the toxic diet were smaller and more densely stained, showing evidence of glycoprotein inside the cell. These findings show that the thyroid gland is affected by the palmitoyl glycerol diet. However, the thyroid is not the only organ affected, because giving either thyroxine or triiodothyronine had no effect on the toxicity of palmitoyl glycerol.

  17. Adaptation to physical training in rats orally supplemented with glycerol.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; de Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Vicente da Costa, Diego; de Oliveira Silva, Víviam; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Rosa, Priscila Vieira; Pereira, Luciano José

    2015-01-01

    We evaluated training adaptation and physical performance parameters in rats orally supplemented with glycerol, glucose, or saline, and submitted to moderate aerobic exercise. Thirty male rats were trained for 6 weeks and administered the supplements during the last 4 weeks of the experiment. Animals were distributed in a completely randomized factorial 2 × 3 design (with or without exercise and 3 substrates). Data were subjected to analysis of variance (ANOVA) and means were compared using the Student-Newmann-Keuls test at 5%. Among the trained animals, none of the substances caused differences in the percentages of protein, fat, or water content in the carcass. Compared with the sedentary animals, the trained animals supplemented with saline and glucose showed a higher protein percentage in the carcass. The relative mass of the heart and adrenal glands was higher in the trained animals. Glycerol improved the protein content in non-trained animals and increased the relative adrenal mass in both groups. Glycerol reduced the variation in levels of lactate and aspartate aminotransferase (AST) during the last exercise session. There was no difference between groups regarding the relative mass of the thymus and gastrocnemius or with the diameter of muscle fibers or the neutrophil-lymphocyte ratio. Supplementation with glycerol was efficient at attenuating variation in AST and lactate levels during exercise. PMID:25474597

  18. Crude glycerol combustion: particulate, acrolein, and other volatile organic emissions

    EPA Science Inventory

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and ...

  19. Conversion of Phosphatidylcholine to PPosphatidylglycerol with phospholipase D and Glycerol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphatidylglycerol (PtdGly) is a relatively rare phospholipid that is useful in lubricant applications. Recently glycerol has become available in large quantities as a byproduct of biodiesel production, allowing for the economical synthesis of PtdGly. The conversion of readily available phosphat...

  20. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives §...

  1. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...

  2. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives §...

  3. Biocomposites Prepared from Fiber Processing Wastes and Glycerol Polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biocomposites were prepared by the addition of flax fiber processing waste to glycerol and adipic acid mixtures. The processing waste consisted of fiber, cuticle, and shive fragments generated during the commercial cleaning of retted flax bast fibers. These waste materials were added at 1, 3, or 5 w...

  4. Dark fermentative bioconversion of glycerol to hydrogen by Bacillus thuringiensis.

    PubMed

    Kumar, Prasun; Sharma, Rishi; Ray, Subhasree; Mehariya, Sanjeet; Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2015-04-01

    Biodiesel manufacturing units discharge effluents rich in glycerol. The need is to convert crude glycerol (CG) into useful products such as hydrogen (H2). Under batch culture, Bacillusthuringiensis EGU45 adapted on pure glycerol (PG, 2% v/v) resulted in an H2 yield of 0.646 mol/mol glycerol consumed on minimal media (250 mL) supplemented with 1% ammonium nitrate at 37°C over 4 days. Here, H2 constituted 67% of the total biogas. Under continuous culture, at 2 days of hydraulic retention time, B. thuringiensis immobilized on ligno-cellulosic materials (banana leaves - BL, 10% v/v) resulted in a H2 yield of 0.386 mol/mol PG consumed. On CG, the maximal H2 yield of 0.393 mol/mol feed consumed was recorded. In brief, B. thuringiensis could transform CG, on limited resources - minimal medium with sodium nitrate, by immobilizing them on cheap and easily available biowaste, which makes it a suitable candidate for H2 production on a large scale. PMID:25686722

  5. Genetically engineered rhamnolipid-producing organism for glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhamnolipid (RL) is a microbial glycolipid currently developed for industrial use as a biobased surfactant. It also possesses antimicrobial activity that is attractive for applications in sanitizing washes. Glycerol byproduct stream from biodiesel production is a promising low-cost substrate for m...

  6. Optimization process of tribenzoine production as a glycerol derived product

    NASA Astrophysics Data System (ADS)

    Widayat, Abdurrakhman, Rifianto, Y.; Abdullah, Hadiyanto, Samsudin, Asep M.; Annisa, A. N.

    2015-12-01

    Tribenzoin is a derived product from glycerol that can produce from glycerol conversion via esterification process. The product can be used in the food industry, cosmetics industry, polymer industry and also can be used to improve the properties of adhesive materials and water resistance in the ink printer.In the other hand, it advantages is environmentally friendly andrenewable because it is not derived from petroleum. This paper discusses the effect of temperature and catalyst concentration for tribenzoin production. For the responses, yield and product composition were observed. Results showed that the highest yield achieved at optimal variable data processed using Central Composite Design (CCD) which is 63.64 temperature (°C), mole ratio of benzoic acidto glycerol is 3.644:1, and catalyst concentration 6.25% (wt% glycerol). Yield products produced 58.71%. FTIR analysis results showed that the samples contained the results of IR spectra wavelength 1761 cm-1 in the fingerprint region and 3165 cm-1 frequency region group. The existence of these two adjustments that fixed in the area is strong evidence that the compound is tribenzoin.

  7. Genetic determinants for enhanced glycerol growth of Saccharomyces cerevisiae.

    PubMed

    Swinnen, Steve; Ho, Ping-Wei; Klein, Mathias; Nevoigt, Elke

    2016-07-01

    The yeast Saccharomyces cerevisiae generally shows a low natural capability to utilize glycerol as the sole source of carbon, particularly when synthetic medium is used and complex supplements are omitted. Nevertheless, wild type isolates have been identified that show a moderate growth under these conditions. In the current study we made use of intraspecies diversity to identify targets suitable for reverse metabolic engineering of the non-growing laboratory strain CEN.PK113-1A. A genome-wide genetic mapping experiment using pooled-segregant whole-genome sequence analysis was conducted, and one major and several minor genetic loci were identified responsible for the superior glycerol growth phenotype of the previously selected S. cerevisiae strain CBS 6412-13A. Downscaling of the major locus by fine-mapping and reciprocal hemizygosity analysis allowed the parallel identification of two superior alleles (UBR2CBS 6412-13A and SSK1CBS 6412-13A). These alleles together with the previously identified GUT1CBS 6412-13A allele were used to replace the corresponding alleles in the strain CEN.PK113-1A. In this way, glycerol growth could be established reaching a maximum specific growth rate of 0.08h(-1). Further improvement to a maximum specific growth rate of 0.11h(-1) could be achieved by heterologous expression of the glycerol facilitator FPS1 from Cyberlindnera jadinii. PMID:26971668

  8. Performance and carcass characteristics of growing pigs fed crude glycerol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Performance and carcass characteristics of growing pigs fed crude glycerol, a co-product of biodiesel production, were determined in a 138-d feeding trial conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. Pigs were weaned at 21d of age and were fed a commercial starter-...

  9. Apparent digestible energy value of crude glycerol fed to pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent digestible energy of crude glycerol, a co-product of biodiesel production, was determined in two studies conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. In the first study, 24 barrows with an average body weight of 11.0 kg were fed 376 g/d of a basal corn...

  10. Synthesis of High-Molecular-Weight Multifunctional Glycerol Polyhydroxyurethanes PHUs.

    PubMed

    Nohra, Bassam; Candy, Laure; Blanco, Jean-François; Raoul, Yann; Mouloungui, Zéphirin

    2016-01-01

    Glycerol carbonate acrylate is a 5-membered cyclic carbonate synthesized from glycerol that is used as a chemical coupling agent and has proven highly suitable for use in the synthesis of multifunctional polyhydroxyurethanes (PHUs). The multifunctionality of the structure of PHUs is determined by the density of the carbon-amine groups generated by the Aza-Michael reaction and that of the urethane groups and adjacent primary and secondary hydroxyl groups generated by aminolysis. Glycerol carbonate acrylate is polymerized with polyfunctional mono-, di-, tri, and tetra-amines, by type-AB polyaddition, either in bulk or in solution, through stepwise or one-pot reaction strategies in the absence of added catalysts. These approaches result in the generation of linear, interchain, and crosslinked structures, through the polyaddition of linear and branched amines to the ethylene and cyclic carbonate sites of glycerol carbonate acrylate. The resulting collection of organic molecules gives rise to polyethylene amino ester PHUs with a high molar mass, exceeding 20,000 g·mol(-1), with uniform dispersity. PMID:27626401

  11. Açai berry extract attenuates glycerol-induced acute renal failure in rats.

    PubMed

    Unis, Amina

    2015-03-01

    Acute renal failure (ARF) is one of the most common problems encountered in hospitalized critically ill patients. In recent years great effort has been focused on the introduction of herbal medicine as a novel therapeutic agent for prevention of ARF. Hence, the current study was designed to investigate the effect of Açai berry extract (ABE) on glycerol-induced ARF in rats. Results of the present study showed that rat groups that received oral ABE in a dose of 100 and 200 mg/kg/day for 7 days before or 7 days after induction of ARF by a single intramuscular glycerol injection reported a significant improvement in kidney functions tests [decrease in serum urea, serum creatinine, and blood urea nitrogen (BUN)] when compared to the ARF model groups. Moreover, there was significant amelioration in renal oxidative stress markers [renal catalase (CAT), renal reduced glutathione (GSH)] and renal histopathological changes in the ABE-treated groups when compared to ARF model groups. The most significant improvement was reported in the groups where ABE was administered in a dose 200 mg/kg/day. These results indicate that ABE has a potential role in ameliorating renal damage involved in ARF. PMID:25524621

  12. Structure and Evolution of the Archaeal Lipid Synthesis Enzyme sn-Glycerol-1-phosphate Dehydrogenase*

    PubMed Central

    Carbone, Vincenzo; Schofield, Linley R.; Zhang, Yanli; Sang, Carrie; Dey, Debjit; Hannus, Ingegerd M.; Martin, William F.; Sutherland-Smith, Andrew J.; Ronimus, Ron S.

    2015-01-01

    One of the most critical events in the origins of cellular life was the development of lipid membranes. Archaea use isoprenoid chains linked via ether bonds to sn-glycerol 1-phosphate (G1P), whereas bacteria and eukaryotes use fatty acids attached via ester bonds to enantiomeric sn-glycerol 3-phosphate. NAD(P)H-dependent G1P dehydrogenase (G1PDH) forms G1P and has been proposed to have played a crucial role in the speciation of the Archaea. We present here, to our knowledge, the first structures of archaeal G1PDH from the hyperthermophilic methanogen Methanocaldococcus jannaschii with bound substrate dihydroxyacetone phosphate, product G1P, NADPH, and Zn2+ cofactor. We also biochemically characterized the enzyme with respect to pH optimum, cation specificity, and kinetic parameters for dihydroxyacetone phosphate and NAD(P)H. The structures provide key evidence for the reaction mechanism in the stereospecific addition for the NAD(P)H-based pro-R hydrogen transfer and the coordination of the Zn2+ cofactor during catalysis. Structure-based phylogenetic analyses also provide insight into the origins of G1PDH. PMID:26175150

  13. CO2 Capillary-Trapping Processes in Deep Saline Aquifers

    NASA Astrophysics Data System (ADS)

    Gershenzon, Naum I.; Soltanian, Mohamadreza; Ritzi, Robert W., Jr.; Dominic, David F.

    2014-05-01

    reservoirs. The results strongly suggest that representing these small scales features, and representing how they are organized within a hierarchy of larger-scale features, is critical to understanding capillary trapping processes. References [1] Bridge, J.S. (2006), Fluvial facies models: Recent developments, in Facies Models Revisited, SEPM Spec. Publ., 84, edited by H. W. Posamentier and R. G. Walker, pp. 85-170, Soc. for Sediment. Geol. (SEPM), Tulsa, Okla [2] Ramanathan, R., A. Guin, R.W. Ritzi, D.F. Dominic, V.L. Freedman, T.D. Scheibe, and I.A. Lunt (2010), Simulating the heterogeneity in channel belt deposits: Part 1. A geometric-based methodology and code, Water Resources Research, v. 46, W04515.

  14. Distribution of metabolic fluxes towards glycerol phosphate and L-lactate from fructose 1,6-biphosphate in vitro: effect of glycerol phosphate dehydrogenase.

    PubMed

    Riol-Cimas, J M; Meléndez-Hevia, E

    1986-01-01

    A metabolic system in vitro, which converts fructose 1,6-biphosphate into the two alternative products, lactate and glycerol phosphate, was designed to study the distribution of metabolic fluxes and, specifically, the control of glycerol phosphate production rate in rat muscle extract. Experiments were carried out at several protein concentrations by dilution of rat muscle extract, showing non-linear behaviours of flux versus protein concentration. These were hyperbolic for glycerol phosphate and logarithmic for L-lactate. The influence of the flux towards any alternate product on the rate giving the other was studied by stimulation of each. Results obtained show that in this system, flux towards glycerol phosphate is not affected by lactate production and the same occurs for the contrary case. Glycerol phosphate dehydrogenase seems to be the only enzyme in this system whose activity controls the flux towards glycerol phosphate. PMID:3758466

  15. Capillary Phenomena at Nanoscales: Electrowetting and Capillary Adhesion

    NASA Astrophysics Data System (ADS)

    Robbins, Mark

    2011-11-01

    Theories of capillary phenomena have traditionally been based on continuum approximations that break down as dimensions shrink to nanometer scales. Molecular simulations are used to test the limits of continuum theory in electrowetting on dielectric (EWOD) and capillary adhesion between solids. In EWOD, a fluid drop is separated from an electrode by a dielectric. Increasing the voltage V between drop and electrode, decreases the contact angle θ, allowing the droplet to be manipulated. Simulations of nanoscale drops show the same behavior as experiments on millimeter drops. The contact angle follows the continuum Young-Lippmann equation (YLE) at low voltages and then saturates. The saturation mechanism has been difficult to identify in experiments. Simulations show that charged molecules are pulled from the drop by large electrostatic forces near the contact line. Saturation can be delayed by increasing molecular binding, lowering temperature or increasing dielectric constant. A local force balance equation is derived that agrees with the YLE below saturation and remains valid after saturation. Simulations of capillary adhesion examined the force between a spherical tip of radius R and a flat substrate. The shape of the meniscus agrees remarkably well with continuum theory down to nanometer separations, as does the adhesive force from interfacial tension. However, the total force may deviate by factors of two or have the opposite sign. While the component of the pressure along the substrate agrees with the Laplace pressure from continuum theory, the out-of âplane component does not. There may also be significant force oscillations associated with layering near the solids. The elastic response of the solid has little affect on adhesive forces. This material is based upon work supported by National Science Foundation Grant No. CMS-0103408.

  16. Capillary channel flow experiments aboard the International Space Station

    NASA Astrophysics Data System (ADS)

    Conrath, M.; Canfield, P. J.; Bronowicki, P. M.; Dreyer, M. E.; Weislogel, M. M.; Grah, A.

    2013-12-01

    In the near-weightless environment of orbiting spacecraft capillary forces dominate interfacial flow phenomena over unearthly large length scales. In current experiments aboard the International Space Station, partially open channels are being investigated to determine critical flow rate-limiting conditions above which the free surface collapses ingesting bubbles. Without the natural passive phase separating qualities of buoyancy, such ingested bubbles can in turn wreak havoc on the fluid transport systems of spacecraft. The flow channels under investigation represent geometric families of conduits with applications to liquid propellant acquisition, thermal fluids circulation, and water processing for life support. Present and near future experiments focus on transient phenomena and conduit asymmetries allowing capillary forces to replace the role of gravity to perform passive phase separations. Terrestrial applications are noted where enhanced transport via direct liquid-gas contact is desired.

  17. Capillary channel flow experiments aboard the International Space Station.

    PubMed

    Conrath, M; Canfield, P J; Bronowicki, P M; Dreyer, M E; Weislogel, M M; Grah, A

    2013-12-01

    In the near-weightless environment of orbiting spacecraft capillary forces dominate interfacial flow phenomena over unearthly large length scales. In current experiments aboard the International Space Station, partially open channels are being investigated to determine critical flow rate-limiting conditions above which the free surface collapses ingesting bubbles. Without the natural passive phase separating qualities of buoyancy, such ingested bubbles can in turn wreak havoc on the fluid transport systems of spacecraft. The flow channels under investigation represent geometric families of conduits with applications to liquid propellant acquisition, thermal fluids circulation, and water processing for life support. Present and near future experiments focus on transient phenomena and conduit asymmetries allowing capillary forces to replace the role of gravity to perform passive phase separations. Terrestrial applications are noted where enhanced transport via direct liquid-gas contact is desired. PMID:24483559

  18. Capillary pumped loop body heat exchanger

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

    1998-01-01

    A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

  19. Rainbow smelt: the unusual case of cryoprotection by sustained glycerol production in an aquatic animal.

    PubMed

    Driedzic, William R

    2015-07-01

    Rainbow smelt flourish at -1.8 °C, the freezing point of sea water. An antifreeze protein contributes to freeze point depression but, more importantly, cryoprotection is due to an elevation in osmotic pressure, by the accumulation of glycerol. The lower the water temperature, the higher the plasma glycerol with levels recorded as high as 400 mmol l(-1). Glycerol freely diffuses out in direct relation to the glycerol concentration and fish may lose as much as 15% of their glycerol reserve per day. Glycerol levels decrease from a maximum in February/March while water temperature is still sub-zero. The decrease in glycerol may respond to a photoperiod signal as opposed to initiation which is triggered by low temperature. The initial increase in glycerol level is supported by liver glycogen but high sustained glycerol level is dependent upon dietary carbohydrate and protein. The metabolic pathways leading to glycerol involve flux from glycogen/glucose to the level of dihydroxyacetone phosphate (DHAP) via the initial part of glycolysis and from amino acids via a truncated gluconeogenesis again to the level of DHAP. DHAP in turn is converted to glycerol 3-phosphate (G3P) and then directly to glycerol. The key to directing DHAP to G3P is a highly active glycerol 3-P dehydrogenase. G3P is converted directly to glycerol via G3P phosphatase, the rate-limiting step in the process. The transition to glycerol production is associated with increased activities of enzymes at key loci in the top part of glycogenolysis/glycolysis. Curtailment of the final section of glycolysis may reside at the level of pyruvate oxidation with an inactivation of pyruvate dehydrogenase (PDH) driven by increased levels of PDH kinase. Enzymes associated with amino acid trafficking are elevated as is the pivotal enzyme phosphoenolpyruvate carboxykinase. PMID:25921795

  20. Intracranial capillary hemangioma mimicking a dissociative disorder

    PubMed Central

    John, Santosh G.; Pillai, Unnikrishnan; Lacasse, Alexander

    2012-01-01

    Capillary hemangiomas, hamartomatous proliferation of vascular endothelial cells, are rare in the central nervous system (CNS). Intracranial capillary hemangiomas presenting with reversible behavioral abnormalities and focal neurological deficits have rarely been reported. We report a case of CNS capillary hemangioma presenting with transient focal neurological deficits and behavioral abnormalities mimicking Ganser's syndrome. Patient underwent total excision of the vascular malformation, resulting in complete resolution of his symptoms. PMID:24765434

  1. Heuristic approach to capillary pressures averaging

    SciTech Connect

    Coca, B.P.

    1980-10-01

    Several methods are available to average capillary pressure curves. Among these are the J-curve and regression equations of the wetting-fluid saturation in porosity and permeability (capillary pressure held constant). While the regression equation seem completely empiric, the J-curve method seems to be theoretically sound due to its expression based on a relation between the average capillary radius and the permeability-porosity ratio. An analysis is given of each of these methods.

  2. Malpighi and the discovery of capillaries.

    PubMed

    Pearce, J M S

    2007-01-01

    Leonardo da Vinci clearly observed and described capillaries. Using the microscope, Marcello Malpighi examined the brain and major organs to demonstrate their finer anatomical features. This led to his discovery in 1661, of capillaries that proved fundamental to our understanding of the vascular system in the brain and cord. He hypothesized that capillaries were the connection between arteries and veins that allowed blood to flow back to the heart in the circulation of the blood, as first asserted by William Harvey. PMID:17851250

  3. Distribution of branched glycerol dialkyl glycerol tetraethers in surface soils of the Qinghai-Tibetan Plateau: implications of brGDGTs-based proxies in cold and dry regions

    NASA Astrophysics Data System (ADS)

    Ding, S.; Xu, Y.; Wang, Y.; He, Y.; Hou, J.; Chen, L.; He, J.-S.

    2015-06-01

    The methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT) based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGT) are useful proxies for the reconstruction of mean annual air temperature (MAT) and soil pH. Recently, a series of 6-methyl brGDGTs were identified which were previously co-eluted with 5-methyl brGDGTs. However, little is known about 6-methyl brGDGTs in the Qinghai-Tibetan Plateau (QTP), a critical region of the global climate system. Here, we analyze 30 surface soils covering a large area of the QTP, among which 6-methyl brGDGTs were the most abundant components (average 53 ± 17% of total brGDGT). The fractional abundance of 6-methyl brGDGTs showed a good correlation with soil pH, while the global MBT'5ME calibration overestimates MAT in the QTP. We therefore proposed a MBT5/6 index including both 5- and 6-methyl brGDGTs, presenting a strong correlation with MAT in QTP: MAT = -20.14 + 39.51 × MBT5/6 (n = 27, r2 = 0.82; RMSE = 1.3 °C). Another index, namely IBT (isomerization of branched tetraether), based on carbon skeleton isomerization of the 5-methyl to 6-methyl brGDGTs, is dependent on soil pH: pH = 6.77 - 1.56 × IBT (n = 27; r2 = 0.74, RMSE = 0.32). Our study suggests that changing the position of methyl group of brGDGTs may be another mechanism for some soil bacteria to adapt to the ambient pH change in addition to the well-known cyclization.

  4. Effects of wetting and anchoring on capillary phenomena in a confined liquid crystal.

    PubMed

    De Las Heras, D; Velasco, E; Mederos, L

    2004-03-01

    A fluid of hard spherocylinders of length-to-breadth ratio L/D=5 confined between two identical planar, parallel walls--forming a pore of slit geometry--has been studied using a version of the Onsager density-functional theory. The walls impose an exclusion boundary condition over the particle's centers of mass, while at the same time favoring a particular anchoring at the walls, either parallel or perpendicular to the substrate. We observe the occurrence of a capillary transition, i.e., a phase transition associated with the formation of a nematic film inside the pore at a chemical potential different from micro(b)-the chemical potential at the bulk isotropic-nematic transition. This transition terminates at an Ising-type surface critical point. In line with previous studies based on the macroscopic Kelvin equation and the mesoscopic Landau-de Gennes approach, our microscopic model indicates that the capillary transition is greatly affected by the wetting and anchoring properties of the semi-infinite system, i.e., when the fluid is in contact with a single wall or, equivalently, the walls are at a very large distance. Specifically, in a situation where the walls are preferentially wetted by the nematic phase in the semi-infinite system, one has the standard scenario with the capillary transition taking place at chemical potentials less than micro(b) (capillary nematization transition or capillary ordering transition). By contrast, if the walls tend to orientationally disorder the fluid, the capillary transition may occur at chemical potentials larger than micro(b), in what may be called a capillary isotropization transition or capillary disordering transition. Moreover, the anchoring transition that occurs in the semi-infinite system may affect very decisively the confinement properties of the liquid crystal and the capillary transitions may become considerably more complicated. PMID:15267357

  5. Identification and Expression of the Genes Encoding a Reactivating Factor for Adenosylcobalamin-Dependent Glycerol Dehydratase

    PubMed Central

    Tobimatsu, Takamasa; Kajiura, Hideki; Yunoki, Michio; Azuma, Muneaki; Toraya, Tetsuo

    1999-01-01

    Adenosylcobalamin-dependent glycerol dehydratase undergoes inactivation by glycerol, the physiological substrate, during catalysis. In permeabilized cells of Klebsiella pneumoniae, the inactivated enzyme is reactivated in the presence of ATP, Mg2+, and adenosylcobalamin. We identified the two open reading frames as the genes for a reactivating factor for glycerol dehydratase and designated them gdrA and gdrB. The reactivation of the inactivated glycerol dehydratase by the gene products was confirmed in permeabilized recombinant Escherichia coli cells coexpressing GdrA and GdrB proteins with glycerol dehydratase. PMID:10383983

  6. Capillary rise kinetics of some building materials.

    PubMed

    Karoglou, M; Moropoulou, A; Giakoumaki, A; Krokida, M K

    2005-04-01

    The presence of water in masonry is one of the main factors in deterioration. Capillary rise is the most usual mechanism of water penetration into building materials. In this study the kinetics of the capillary rise phenomenon was studied for various building materials: four stones, two bricks, and six plasters. A first-order kinetic model was proposed, in which the equilibrium moisture height derived from Darcy law. The capillary height time constant found to be strongly affected by the material characteristics. Moreover, the capillary height time constant can be predicted if the average pore radius of the materials is known. PMID:15752811

  7. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  8. Atlantic cod (Gadus morhua) larvae can biosynthesis phospholipid de novo from 2-oleoyl-glycerol and glycerol precursors.

    PubMed

    Li, Keshuai; Olsen, Rolf Erik; Østensen, Mari-Ann; Altin, Dag; Kjørsvik, Elin; Olsen, Yngvar

    2016-02-01

    The dietary requirement of phospholipid (PL) of fish larvae has been suggested to originate in an inefficient ability for de novo biosynthesis of PL based on dietary triacylglycerol (TAG). The main objective of the present study was to investigate whether cod larvae could synthesis PL from sn-2-monoacylglycerol (2-MAG) and glycerol precursors. A tube feeding method was used to deliver equal molar aliquots of 2-oleoyl-[1,2,3-(3)H]glycerol and [U-(14)C] glycerol together with bovine serum albumin (BSA) bound 16:0 (palmitic acid) and 22:6n-3 (docosahexaenoic acid, DHA), with or without choline chloride to the foregut of anesthetized cod larvae and thereafter monitoring the metabolism of these components in the larvae through 4 h following injection. Our results showed that both 2-MAG and glycerol precursors contributed to the de novo synthesis of phosphatidylcholine (PC) and the 2-MAG pathway predominated over the G-3-P (glycerol-3-phosphate) pathway in the synthesis of TAG and PC. The molecular ratio of PC/TAG obtained from the 2-MAG and the G-3-P pathways was 0.44-0.74 and 1.02-2.06 within the first hour of tube feeding, suggesting they might have comparable biosynthesis ability of PC and TAG under the conditions of the present study. Furthermore, supplementation of choline chloride significantly increased PC/TAG ratio (p < 0.05) for both pathways. However, further studies are needed to quantify the enzyme activity involved in the CDP-choline (cytidine diphosphate choline) pathway, and the function of choline either in simulating PC synthesis or TAG catabolism or both needs further investigation. PMID:26349454

  9. Microfoam formation in a capillary.

    PubMed

    Kotopoulis, Spiros; Postema, Michiel

    2010-02-01

    The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source. In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1-10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena. We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces. We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall. Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation. PMID:19875143

  10. Expression and functional studies of genes involved in transport and metabolism of glycerol in Pachysolen tannophilus

    PubMed Central

    2013-01-01

    Background Pachysolen tannophilus is a non-conventional yeast, which can metabolize many of the carbon sources found in low cost feedstocks including glycerol and xylose. The xylose utilisation pathways have been extensively studied in this organism. However, the mechanism behind glycerol metabolism is poorly understood. Using the recently published genome sequence of P. tannophilus CBS4044, we searched for genes with functions in glycerol transport and metabolism by performing a BLAST search using the sequences of the relevant genes from Saccharomyces cerevisiae as queries. Results Quantitative real-time PCR was performed to unveil the expression patterns of these genes during growth of P. tannophilus on glycerol and glucose as sole carbon sources. The genes predicted to be involved in glycerol transport in P. tannophilus were expressed in S. cerevisiae to validate their function. The S. cerevisiae strains transformed with heterologous genes showed improved growth and glycerol consumption rates with glycerol as the sole carbon source. Conclusions P. tannophilus has characteristics relevant for a microbial cell factory to be applied in a biorefinery setting, i.e. its ability to utilise the carbon sources such as xylose and glycerol. However, the strain is not currently amenable to genetic modification and transformation. Heterologous expression of the glycerol transporters from P. tannophilus, which has a relatively high growth rate on glycerol, could be used as an approach for improving the efficiency of glycerol assimilation in other well characterized and applied cell factories such as S. cerevisiae. PMID:23514356

  11. Exotic containers for capillary surfaces

    NASA Technical Reports Server (NTRS)

    Concus, Paul; Finn, Robert

    1991-01-01

    This paper discusses 'exotic' rotationally symmetric containers that admit an entire continuum of distinct equilibrium capillary free surfaces. The paper extends earlier work to a larger class of parameters and clarifies and simplifies the governing differential equations, while expressing them in a parametric form appropriate for numerical integration. A unified presentation suitable for both zero and nonzero gravity is given. Solutions for the container shapes are depicted graphically along with members of the free-surface continuum, and comments are given concerning possible physical experiments.

  12. Microbeam-coupled capillary electrophoresis.

    PubMed

    Garty, G; Ehsan, M U; Buonanno, M; Yang, Z; Sweedler, J V; Brenner, D J

    2015-09-01

    Within the first few microseconds following a charged particle traversal of a cell, numerous oxygen and nitrogen radicals are formed along the track. Presented here is a method, using capillary electrophoresis, for simultaneous measurement, within an individual cell, of specific reactive oxygen species, such as the superoxide radical ([Formula: see text]) as well as the native and oxidised forms of glutathione, an ubiquitous anti-oxidant that assists the cell in coping with these species. Preliminary data are presented as well as plans for integrating this system into the charged particle microbeam at Columbia University. PMID:25870435

  13. Capillary rafts and their destabilization

    NASA Astrophysics Data System (ADS)

    Protiere, Suzie; Abkarian, Manouk; Aristoff, Jeffrey; Stone, Howard

    2010-11-01

    Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. The study of such particle-laden interfaces is therefore of practical as well as fundamental importance. Here we report experiments on the self-assembly of spherical particles into capillary rafts at an oil-water interface and elucidate how such rafts sink. We characterize different types of sinking behavior and show that it is possible to obtain "armored droplets," whereby the sinking oil is encapsulated within a shell of particles.

  14. Capillary electrophoresis in metallodrug development.

    PubMed

    Holtkamp, Hannah; Hartinger, Christian G

    2015-09-01

    Capillary electrophoresis (CE) is a separation method based on differential migration of analytes in electric fields. The compatibility with purely aqueous separation media makes it a versatile tool in metallodrug research. Many metallodrugs undergo ligand exchange reactions that can easily be followed with this method and the information gained can even be improved by coupling the CE to advanced detectors, such as mass spectrometers. This gives the method high potential to facilitate the development of metallodrugs, especially when combined with innovative method development and experimental design. PMID:26547417

  15. High pressure pulsed capillary viscometry

    NASA Technical Reports Server (NTRS)

    Smith, R. L.; Walowitt, J. A.; Pan, C. H. T.

    1972-01-01

    An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

  16. Characterization of the proteostasis roles of glycerol accumulation, protein degradation and protein synthesis during osmotic stress in C. elegans.

    PubMed

    Burkewitz, Kristopher; Choe, Keith P; Lee, Elaine Choung-Hee; Deonarine, Andrew; Strange, Kevin

    2012-01-01

    Exposure of C. elegans to hypertonic stress-induced water loss causes rapid and widespread cellular protein damage. Survival in hypertonic environments depends critically on the ability of worm cells to detect and degrade misfolded and aggregated proteins. Acclimation of C. elegans to mild hypertonic stress suppresses protein damage and increases survival under more extreme hypertonic conditions. Suppression of protein damage in acclimated worms could be due to 1) accumulation of the chemical chaperone glycerol, 2) upregulation of protein degradation activity, and/or 3) increases in molecular chaperoning capacity of the cell. Glycerol and other chemical chaperones are widely thought to protect proteins from hypertonicity-induced damage. However, protein damage is unaffected by gene mutations that inhibit glycerol accumulation or that cause dramatic constitutive elevation of glycerol levels. Pharmacological or RNAi inhibition of proteasome and lyosome function and measurements of cellular protein degradation activity demonstrated that upregulation of protein degradation mechanisms plays no role in acclimation. Thus, changes in molecular chaperone capacity must be responsible for suppressing protein damage in acclimated worms. Transcriptional changes in chaperone expression have not been detected in C. elegans exposed to hypertonic stress. However, acclimation to mild hypertonicity inhibits protein synthesis 50-70%, which is expected to increase chaperone availability for coping with damage to existing proteins. Consistent with this idea, we found that RNAi silencing of essential translational components or acute exposure to cycloheximide results in a 50-80% suppression of hypertonicity-induced aggregation of polyglutamine-YFP (Q35::YFP). Dietary changes that increase protein production also increase Q35::YFP aggregation 70-180%. Our results demonstrate directly for the first time that inhibition of protein translation protects extant proteins from damage brought

  17. The Role of Glycerol in the Osmotic Regulation of the Halophilic Alga Dunaliella parva

    PubMed Central

    Ben-Amotz, Ami; Avron, Mordhay

    1973-01-01

    Dunaliella parva, a green halophilic alga, was found to accumulate very large amounts of intracellular glycerol. Through measurements of the intracellular volume the internal concentration of glycerol was calculated and found to be around 2.1 m in cells cultured in 1.5 m NaCl. When the extracellular salt concentration of an algal suspension was increased or decreased, the intracellular glycerol varied accordingly, reaching its new osmotic equilibrium after about 90 minutes. Since no leakage of intracellular glycerol was observed above 0.6 m NaCl, these alterations in glycerol content are interpreted as due to metabolic formation and degradation of intracellular glycerol. The above results indicate the existence of a new type of algal osmoregulation, in which the osmotic balance depends on the synthesis or degradation of intracellular glycerol in response to the external salt concentration. PMID:16658431

  18. Effect of crude glycerol impurities on lipid preparation by Rhodosporidium toruloides yeast 32489.

    PubMed

    Gao, Zhen; Ma, Yingqun; Wang, Qunhui; Zhang, Min; Wang, Juan; Liu, Yu

    2016-10-01

    Crude glycerol (byproduct of biodiesel preparation) was utilised as the carbon source to produce lipid using oleaginous yeast Rhodosporidium toruloides 32489. Under the same conditions, lipid production with crude glycerol was higher than those produced with glucose and pure glycerol. The effects of 4 main impurities in crude glycerol (methyl oleate, sodium oleate, NaCl and methanol) on lipid production were investigated. Compared with utilising pure glycerol, addition of methyl oleate, sodium oleate, and NaCl impurities increased lipid production by 47.0%, 68.0% and 64.0%, respectively, while methanol decreased lipid production by 17.7%. However, when methanol was mixed with other impurities, its inhibition effect was alleviated due to the promoting effect of other impurities. Hence, crude glycerol could be used as a renewable and low-cost carbon source to replace pure glucose or glycerol for lipid preparation. PMID:27387413

  19. Dynamics of solvent and rotational relaxation of glycerol in the nanocavity of reverse micelles.

    PubMed

    Chakraborty, Anjan; Seth, Debabrata; Setua, Palash; Sarkar, Nilmoni

    2006-03-23

    The dynamics of solvent and rotational relaxation of Coumarin 480 and Coumarin 490 in glycerol containing bis-2-ethyl hexyl sulfosuccinate sodium salt (AOT) reverse micelles have been investigated with steady-state and time-resolved fluorescence spectroscopy. We observed slower solvent relaxation of glycerol confined in the nanocavity of AOT reverse micelles compared to that in pure glycerol. However, the slowing down in the solvation time on going from neat glycerol to glycerol confined reverse micelles is not comparable to that on going from pure water or acetonitrile to water or acetonitrile confined AOT reverse micellar aggregates. While solvent relaxation times were found to decrease with increasing glycerol content in the reverse micellar pool, rotational relaxation times were found to increase with increase in glycerol content. PMID:16539469

  20. Glycerol dialkyl glycerol tetraethers preserved in stalagmites: a new continental palaeothermometer

    NASA Astrophysics Data System (ADS)

    Blyth, A. J.; Schouten, S.

    2010-12-01

    The ability to recover reliable temperature records is central to palaeoclimatic research, informing our understanding of the past and our models of the future. However, there is a need for new quantitative terrestrial temperature proxies. Here we present a novel palaeothermometer, combining molecular temperature proxies with the strong dating control and established environmental records provided by stalagmites. The results show good correlations between known and calculated temperatures, suggesting that the approach has considerable potential as a climatic proxy. Glycerol dialkyl glycerol tetraethers (GDGTs) are microbial membrane lipids, which vary in structure with temperature and pH [1]. In the terrestrial realm, the focus is on bacterially derived GDGTs, which have been used to measure terrestrial organic matter input to aquatic deposits via the BIT index [2], and developed into a temperature related index (MBT/CBT) in soils and near-shore marine sediments (MBT/CBT), based upon the degree of branching and cyclicisation of the carbon skeleton [3]. Stalagmites form an ideal archive for terrestrial climate records, as they are stable, can be easily dated, and contain a number of environmental proxies (stable isotopes, trace elements, organic matter etc). Attempts have been made to develop inorganic temperature proxies in stalagmites, most recently using isotopic analysis of fluid inclusions. However, the use of organic temperature proxies in this context is largely unstudied. Thirty-eight stalagmite or stalactite samples from twenty-one sites around the world were analysed for their GDGT content. Calcite samples were cleaned and decalcified with HCl, and lipids extracted into dichloromethane via liquid-liquid extraction. Each extract was then prepared and analysed via HPLC-MS following Weijers et al. [3]. The results show low but usable levels of GDGTs in all but one sample. Peak size measurements were made for all recognised compounds associated with BIT and

  1. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

    PubMed Central

    2013-01-01

    Background Pretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined. Results Pretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity. Conclusions Acidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained

  2. Quantitative analysis of the fermentative metabolism of glycerol in Escherichia coli.

    PubMed

    Cintolesi, Angela; Clomburg, James M; Rigou, Venetia; Zygourakis, Kyriacos; Gonzalez, Ramon

    2012-01-01

    Availability, low price, and high degree of reduction have made glycerol a highly attractive and exploited carbon source for the production of fuels and reduced chemicals. Here we report the quantitative analysis of the fermentative metabolism of glycerol in Escherichia coli through the use of kinetic modeling and metabolic control analysis (MCA) to gain a better understanding of glycerol fermentation and identify key targets for genetic manipulation that could enhance product synthesis. The kinetics of glycerol fermentation in a batch culture was simulated using a dynamic model consisting of mass balances for glycerol, ethanol, biomass, and 11 intracellular metabolites, along with the corresponding kinetic expressions for the metabolism of each species. The model was then used to calculate metabolic control coefficients and elucidate the control structure of the pathways involved in glycerol utilization and ethanol synthesis. The calculated flux control coefficients indicate that the glycolytic flux during glycerol fermentation is almost exclusively controlled by the enzymes glycerol dehydrogenase (encoded by gldA) and dihydroxyacetone kinase (DHAK) (encoded by dhaKLM). In agreement with the MCA findings, overexpression of gldA and dhaKLM led to significant increase in glycerol utilization and ethanol synthesis fluxes. Moreover, overexpression of other enzymes involved in the pathways that mediate glycerol utilization and its conversion to ethanol had no significant impact on glycerol utilization and ethanol synthesis, further validating the MCA predictions. These findings were then applied as a means of increasing the production of ethanol: overexpression of glycerol dehyrdogenase and DHAK enabled the production of 20 g/L ethanol from crude glycerol, a by-product of biodiesel production, indicating the potential for industrial scale conversion of waste glycerol to ethanol under anaerobic conditions. PMID:21858785

  3. Microbial conversion of glycerol into glycolipid biosurfactants, mannosylerythritol lipids, by a basidiomycete yeast, Pseudozyma antarctica JCM 10317(T).

    PubMed

    Morita, Tomotake; Konishi, Masaaki; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2007-07-01

    Microbial conversion of glycerol into functional bio-based materials was investigated, aiming to facilitate the utilization of waste glycerol. A basidiomycete yeast, Pseudozyma antarctica JCM 10317, efficiently produced mannosylerythritol lipids (MELs) as glycolipid biosurfactants from glycerol. The amount of MEL yield reached 16.3 g l(-1) by intermittent feeding of glycerol. PMID:17697987

  4. Evaluation of capillary reinforced composites

    NASA Technical Reports Server (NTRS)

    Cahill, J. E.; Halase, J. F.; South, W. K.; Stoffer, L. J.

    1985-01-01

    Anti-icing of the inlet of jet engines is generally performed with high pressure heated air that is directed forward from the compressor through a series of pipes to various manifolds located near the structures to be anti-iced. From these manifolds, the air is directed to all flowpath surfaces that may be susceptible to ice formation. There the anti-icing function may be performed by either heat conduction or film heating. Unfortunately, the prospect of utilizing lighweight, high strength composites for inlet structures of jet engines has been frustrated by the low transverse thermal conductivity of such materials. It was the objective of this program to develop an advanced materials and design concept for anti-icing composite structures. The concept that was evaluated used capillary glass tubes embedded on the surface of a composite structure with heated air ducted through the tubes. An analytical computer program was developed to predict the anti-icing performance of such tubes and a test program was conducted to demonstrate actual performance of this system. Test data and analytical code results were in excellent agreement. Both indicate feasibility of using capillary tubes for surface heating as a means for composite engine structures to combat ice accumulation.

  5. Capillary Rise in Porous Media.

    PubMed

    Lago, Marcelo; Araujo, Mariela

    2001-02-01

    Capillary rise experiments were performed in columns filled with glass beads and Berea sandstones, using visual methods to register the advance of the water front. For the glass bead filled columns, early time data are well fitted by the Washburn equation. However, in the experiments, the advancing front exceeded the predicted equilibrium height. For large times, an algebraic behavior of the velocity of the front is observed (T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)). A model for studying the capillary pressure evolution in a regular assembly of spheres is proposed and developed. It is based on a quasi-static advance of the meniscus with a piston-like motion and allows us to estimate the hydraulic equilibrium height, with values very close to those obtained by fitting early time data to a Washburn equation. The change of regime is explained as a transition in the mechanism of advance of the meniscus. On the other hand, only the Washburn regime was observed for the sandstones. The front velocity was fitted to an algebraical form with an exponent close to 0.5, a value expected from the asymptotic limit of the Washburn equation. Copyright 2001 Academic Press. PMID:11161488

  6. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  7. Cryogenic Capillary Screen Heat Entrapment

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L.G.; Hastings, L.J.; Stathman, G.

    2007-01-01

    Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of sub-cooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs.?"Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 data it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

  8. 1,3-Propanediol production from glycerol with Lactobacillus diolivorans.

    PubMed

    Pflügl, Stefan; Marx, Hans; Mattanovich, Diethard; Sauer, Michael

    2012-09-01

    The aim of this study was to evaluate the natural producer Lactobacillus diolivorans as potential production organism of 1,3-propanediol from glycerol. Different cultivation parameters, such as oxygen supply, feeding-strategy, or medium composition have been tested in batch and fed-batch cultivations. The 1,3-propanediol concentration obtained in batch cultivations was 41.7 g/l. This could be increased to 73.7 g/l in a fed-batch co-feeding glucose and glycerol with a molar ratio of 0.1. Yeast extract as part of the MRS cultivation medium could be replaced by nicotinic acid and riboflavin. Furthermore, the addition of Vitamin B(12) to the culture medium increased production by 15% to a final titer of 84.5 g/l 1,3-propanediol. PMID:22728193

  9. Modified silica-based heterogeneous catalysts for etherification of glycerol

    NASA Astrophysics Data System (ADS)

    Gholami, Zahra; Abdullah, Ahmad Zuhairi; Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-01

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca1.6La0.6/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  10. [Sn-glycerol-3-phosphate acyltransferases (GPATs) in plants].

    PubMed

    Liu, Cong; Xiao, Dan-Wang; Shi, Chun-Lin; Hu, Xue-Fang; Wu, Ke-Bin; Guan, Chun-Yun; Xiong, Xing-Hua

    2013-12-01

    Sn-glycerol-3-phosphate acyltransferase (GPAT) catalyzes the acylation at sn-1 position of glycerol-3-phosphate to produce lysophosphatidic acid (LPA) in an acyl-CoA or acyl-ACP-dependent manner, which is the initial and rate-determining step of TAG biosynthetic pathway. Some GPATs have sn-2 transfer activity. Part members of the GPAT gene family have been cloned from different plant species. Based on their subcellular localizations, GPATs can be classified into three types, plastid GPATs, mitochondria GPATs and endoplasmic reticulum GPATs. GPATs exhibit diverse biochemical properties and are involved in synthesis of several lipids such as TAG, suberin, and cutin which play important roles in the growth and development of plants. This review summarized the current understanding of the chromosomal locus and gene structure of GPAT genes and the subcellular localization, sn-2 regiospecificity, substrates specialty, and functions of GPATs in plants. PMID:24645344

  11. Biomass Pretreatment using Ionic Liquid and Glycerol Mixtures

    NASA Astrophysics Data System (ADS)

    Lynam, Joan Goerss

    Lignocellulosic biomass is a renewable, sustainable resource that can replace or supplement fossil fuels use for liquid fuels and chemicals. However, its recalcitrant structure including interwoven cellulose, hemicelluloses, and lignin biomacromolecules is challenging to deconstruct. Pretreating biomass so that it can be converted to useful liquids dominates process economics. Many pretreatment methods exist, but most require hazardous chemicals or processing conditions. Many ionic liquids (ILs), salts molten below 100°C, can be used to deconstruct lignocellulosic biomass and are less hazardous than the volatile organic compounds typically used. While effective, relatively safe, and recyclable, ILs are expensive. To reduce costs, dilution with other safe compounds is desirable, if there is no impact on deconstruction efficiency. Glycerol, a food additive, is inexpensive and becoming even more so since it is a by-product of the burgeoning biodiesel industry. Use of glycerol as an additive or diluent for ILs is extensively evaluated in this work. Rice hulls are an abundant biomass, with over 100 million tons produced per year, but with little practical use. The IL 1-ethyl-3-methylimidazolium formate ([C2mim][O2CH] or EMIM Form) when mixed with an equal amount of glycerol has been shown to be effective in pretreating rice hulls. Ambient pressure, a pretreatment temperature of 110°C, and a reaction time of three hours produced rice hulls that could be enzymatically hydrolyzed to give reasonably good glucose and xylose yields considering the recalcitrance of this silica-armored biomass. The IL [C2mim][O2CH] was also effective when mixed with an equal amount of glycerol to pretreat loblolly pine, a fast-growing softwood. Loblolly pine was pretreated at 140°C for three hours to produce a solid rich in cellulose and hemicelluloses, while a lignin-rich product could be precipitated from the IL. Similar products were obtained from pretreatment with a mixture of 75% 1

  12. The effect of glycerol treatment on crab muscle fibres

    PubMed Central

    Papir, Dalia

    1973-01-01

    1. Membrane constants of the closer muscle of the ghost crab, Ocypoda cursor, were determined before and after treatment in hypertonic glycerol solution and return to an artificial sea-water (A.S.W.) solution. 2. Muscle contraction was abolished after return of the muscle to A.S.W. 3. The membrane capacitance was reduced from 29·0 μF/cm2 to 10·5 μF/cm2. 4. Other passive properties of the muscle membrane, not dependent on capacitance, were not changed. 5. The presynaptic nerve, transmitter release, post-synaptic sensitivity to transmitter and ionic mechanisms of synaptic action were unaffected by glycerol treatment. 6. More than 60% of the membrane capacitance/unit area is contributed by the complex tubular system. 7. The tubular system in crustacea is necessary for excitation-contraction coupling. PMID:4708897

  13. Probing protein stabilization by glycerol using electrospray mass spectrometry.

    PubMed

    Grandori, R; Matecko, I; Mayr, P; Müller, N

    2001-08-01

    This study shows that electrospray ionization mass spectrometry (ESI-MS), combined with a heated turbo ion-spray interface, allows monitoring protein stabilization by glycerol in solution. Measurements obtained with the two proteins lysozyme and cytochrome c are presented. The observed mass-to-charge (m/z) distributions reveal the stabilizing effect of the additive on the protein conformations against temperature and acid-induced unfolding, as well as against denaturation by acetonitrile. The data obtained with lysozyme allow detection of minor conformational changes upon glycerol addition to the native protein, and suggest that the protein structure in the presence of the additive is slightly compressed compared with its state in water. This result corroborates previous evidence obtained by nuclear magnetic resonance. It is also shown that analysis of the m/z distributions obtained by ESI-MS can lead to detection of partially folded and partially populated states in protein samples. PMID:11523091

  14. Modified silica-based heterogeneous catalysts for etherification of glycerol

    SciTech Connect

    Gholami, Zahra; Abdullah, Ahmad Zuhairi Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-22

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca{sub 1.6}La{sub 0.6}/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  15. Influence of heat shock on glycerol production in alcohol fermentation.

    PubMed

    Berovic, Marin; Pivec, Aleksandra; Kosmerl, Tatjana; Wondra, Mojmir; Celan, Stefan

    2007-02-01

    The influence of single and double heat shocks induced during the exponential growth phase of the Saccharomyces cerevisiae fermentation of cultivar Sauvignon Blanc grape must was examined. Rapid temperature changes from 18 degrees C to 34 degrees C have been applied. The effect of the duration of exposure to a high temperature has been analyzed. By the applications of a single heat shock and a double heat shock, up to 8.2 g l(-1) and 11.0 g l(-1) glycerol have been produced, respectively. To prevent the evaporation of fine wine bouquet compounds during the temperature changes, reflux coolers on the top of bioreactors have been employed. By using this method, glycerol production was increased by up to 65%. PMID:17368395

  16. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  17. Glycerol-3-Phosphate-Induced Catabolite Repression in Escherichia coli

    PubMed Central

    Eppler, Tanja; Postma, Pieter; Schütz, Alexandra; Völker, Uwe; Boos, Winfried

    2002-01-01

    The formation of glycerol-3-phosphate (G3P) in cells growing on TB causes catabolite repression, as shown by the reduction in malT expression. For this repression to occur, the general proteins of the phosphoenolpyruvate-dependent phosphotransferase system (PTS), in particular EIIAGlc, as well as the adenylate cyclase and the cyclic AMP-catabolite activator protein system, have to be present. We followed the level of EIIAGlc phosphorylation after the addition of glycerol or G3P. In contrast to glucose, which causes a dramatic shift to the dephosphorylated form, glycerol or G3P only slightly increased the amount of dephosphorylated EIIAGlc. Isopropyl-β-d-thiogalactopyranoside-induced overexpression of EIIAGlc did not prevent repression by G3P, excluding the possibility that G3P-mediated catabolite repression is due to the formation of unphosphorylated EIIAGlc. A mutant carrying a C-terminally truncated adenylate cyclase was no longer subject to G3P-mediated repression. We conclude that the stimulation of adenylate cyclase by phosphorylated EIIAGlc is controlled by G3P and other phosphorylated sugars such as d-glucose-6-phosphate and is the basis for catabolite repression by non-PTS compounds. Further metabolism of these compounds is not necessary for repression. Two-dimensional polyacrylamide gel electrophoresis was used to obtain an overview of proteins that are subject to catabolite repression by glycerol. Some of the prominently repressed proteins were identified by peptide mass fingerprinting. Among these were periplasmic binding proteins (glutamine and oligopeptide binding protein, for example), enzymes of the tricarboxylic acid cycle, aldehyde dehydrogenase, Dps (a stress-induced DNA binding protein), and d-tagatose-1,6-bisphosphate aldolase. PMID:12003946

  18. Selective oxidation of glycerol under acidic conditions using gold catalysts

    SciTech Connect

    Villa, Alberto; Veith, Gabriel M; Prati, Laura

    2010-01-01

    H-mordenite-supported PtAu nanoparticles are highly active and selective in the oxidation of glycerol under acidic conditions, which allows the direct preparation of free acids (see picture). The high selectivity for C{sub 3} compounds results from the negligible formation of H{sub 2}O{sub 2}, in contrast to PtAu nanoparticles supported on activated carbon.

  19. Metabolic Engineering of Glycerol Production in Saccharomyces cerevisiae

    PubMed Central

    Overkamp, Karin M.; Bakker, Barbara M.; Kötter, Peter; Luttik, Marijke A. H.; van Dijken, Johannes P.; Pronk, Jack T.

    2002-01-01

    Inactivation of TPI1, the Saccharomyces cerevisiae structural gene encoding triose phosphate isomerase, completely eliminates growth on glucose as the sole carbon source. In tpi1-null mutants, intracellular accumulation of dihydroxyacetone phosphate might be prevented if the cytosolic NADH generated in glycolysis by glyceraldehyde-3-phosphate dehydrogenase were quantitatively used to reduce dihydroxyacetone phosphate to glycerol. We hypothesize that the growth defect of tpi1-null mutants is caused by mitochondrial reoxidation of cytosolic NADH, thus rendering it unavailable for dihydroxyacetone-phosphate reduction. To test this hypothesis, a tpi1Δ nde1Δ nde2Δ gut2Δ quadruple mutant was constructed. NDE1 and NDE2 encode isoenzymes of mitochondrial external NADH dehydrogenase; GUT2 encodes a key enzyme of the glycerol-3-phosphate shuttle. It has recently been demonstrated that these two systems are primarily responsible for mitochondrial oxidation of cytosolic NADH in S. cerevisiae. Consistent with the hypothesis, the quadruple mutant grew on glucose as the sole carbon source. The growth on glucose, which was accompanied by glycerol production, was inhibited at high-glucose concentrations. This inhibition was attributed to glucose repression of respiratory enzymes as, in the quadruple mutant, respiratory pyruvate dissimilation is essential for ATP synthesis and growth. Serial transfer of the quadruple mutant on high-glucose media yielded a spontaneous mutant with much higher specific growth rates in high-glucose media (up to 0.10 h−1 at 100 g of glucose · liter−1). In aerated batch cultures grown on 400 g of glucose · liter−1, this engineered S. cerevisiae strain produced over 200 g of glycerol · liter−1, corresponding to a molar yield of glycerol on glucose close to unity. PMID:12039737

  20. Enhanced succinate production from glycerol by engineered Escherichia coli strains.

    PubMed

    Li, Qing; Wu, Hui; Li, Zhimin; Ye, Qin

    2016-10-01

    In this study, an engineered strain Escherichia coli MLB (ldhA(-)pflB(-)) was constructed for production of succinate from glycerol. The succinate yield was 0.37mol/mol in anaerobic culture, however, the growth and glycerol consumption rates were very slow, resulting in a low succinate level. Two-stage fermentation was performed in flasks, and the succinate yield reached 0.93mol/mol, but the succinate titer was still low. Hence, overexpression of malate dehydrogenase, malic enzyme, phosphoenolpyruvate (PEP) carboxylase and PEP carboxykinase (PCK) from E. coli, and pyruvate carboxylase from Corynebacterium glutamicum in MLB was investigated for improving succinate production. Overexpression of PCK resulted in remarkable enhancement of glycerol consumption and succinate production. In flask experiments, the succinate concentration reached 118.1mM, and in a 1.5-L bioreactor the succinate concentration further increased to 360.2mM. The highest succinate yield achieved 0.93mol/mol, which was 93% of the theoretical yield, in the anaerobic stage. PMID:27371794

  1. Effect of gravity on capillary instability of liquid jets.

    PubMed

    Amini, Ghobad; Ihme, Matthias; Dolatabadi, Ali

    2013-05-01

    The effect of gravity on the onset and growth rate of capillary instabilities in viscous liquid jets is studied. To this end, a spatial linear stability analysis of Cosserat's equations is performed using a multiscale expansion technique. A dispersion relation and expressions for the perturbation amplitude are derived to evaluate the growth rate of the most unstable axisymmetric disturbance mode. Modeling results are compared with classical results in the limit of zero Bond number, confirming the validity of this approach. Expressions for the critical Weber number, demarcating the transition between convective and absolute instability are derived as functions of capillary and Bond numbers. Parametric investigations for a range of relevant operating conditions (characterized by capillary, Weber, and Bond numbers) are performed to examine the jet breakup and the perturbation growth rate. In addition to the physical insight that is obtained from this investigation, the results that are presented in this work could also be of relevance as test cases for the algorithmic development and the verification of high-fidelity multiphase simulation codes. PMID:23767630

  2. An effective model of blood flow in capillary beds.

    PubMed

    Acosta, Sebastian; Penny, Daniel J; Rusin, Craig G

    2015-07-01

    In this article we derive applicable expressions for the macroscopic compliance and resistance of microvascular networks. This work yields a lumped-parameter model to describe the hemodynamics of capillary beds. Our derivation takes into account the multiscale nature of capillary networks, the influence of blood volume and pressure on the effective resistance and compliance, as well as, the nonlinear interdependence between these two properties. As a result, we obtain a simple and useful model to study hypotensive and hypertensive phenomena. We include two implementations of our theory: (i) pulmonary hypertension where the flow resistance is predicted as a function of pulmonary vascular tone. We derive from first-principles the inverse proportional relation between resistance and compliance of the pulmonary tree, which explains why the RC factor remains nearly constant across a population with increasing severity of pulmonary hypertension. (ii) The critical closing pressure in pulmonary hypotension where the flow rate dramatically decreases due to the partial collapse of the capillary bed. In both cases, the results from our proposed model compare accurately with experimental data. PMID:25936622

  3. Capillary Movement in Granular Beds in Microgravity

    NASA Technical Reports Server (NTRS)

    Yendler, Boris S.; Bula, Ray J.; Kliss, Mark (Technical Monitor)

    1996-01-01

    Understanding the dynamics of capillary flow through unsaturated porous media is very important for the development of an effective water and nutrient delivery system for growing plants in microgravity and chemical engineering applications. Experiments were conducted on the Space Shuttle during the STS-63 mission using three experimental cuvettes called "Capillary Testbed-M." These experiments studied the effect of bead diameter on capillary flow by comparing the capillary flow in three different granular beds. It was observed that the speed of water propagation in the granular bed consisting of 1.5 mm diameter particles was less than that in the bed consisting of 1.0 mm. diameter particles. Such results contradict the existing theory of capillary water propagation in granular beds. It was found also that in microgravity water propagates independently in adjacent layers of a layered granular bed .

  4. Intracranial capillary hemangioma in an elderly patient

    PubMed Central

    Okamoto, Ai; Nakagawa, Ichiro; Matsuda, Ryosuke; Nishimura, Fumihiko; Motoyama, Yasushi; Park, Young-Su; Nakamura, Mitsutoshi; Nakase, Hiroyuki

    2015-01-01

    Background: Capillary hemangiomas are neoplasms involving skin and soft tissue in infants. These lesions rarely involved an intracranial space and reported age distribution ranges from infancy to middle age. We report an extremely rare case of rapidly rising intracranial capillary hemangioma in an elderly woman. Case Description: The 82-year-old woman presented with vomiting, reduced level of consciousness, and worsening mental state. Computed tomography showed a contrast-enhanced extra-axial lesion in the left frontal operculum, although no intracranial mass lesion was identifiable from magnetic resonance imaging taken 2 years earlier. Complete surgical excision was performed and histopathological examination diagnosed benign capillary hemangioma consisting of a variety of dilated capillary blood vessels lined by endothelial cells. Conclusion: This is the first description of rapid growth of an intracranial capillary hemangioma in an elderly woman. These lesions are exceedingly rare in the elderly population, but still show the capacity for rapid growth. Complete excision would prevent further recurrence. PMID:26664868

  5. Modeling capillary barriers in unsaturated fractured rock

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Shu; Zhang, W.; Pan, Lehua; Hinds, Jennifer; Bodvarsson, G. S.

    2002-11-01

    This work presents a series of numerical modeling studies that investigate the hydrogeologic conditions required to form capillary barriers and the effect that capillary barriers have on fluid flow and tracer transport processes in the unsaturated fractured rock of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. The modeling approach is based on a dual-continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. The numerical modeling results showed that effective capillary barriers can develop where both matrix and fracture capillary gradients tend to move water upward. Under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary barrier effects exist for diverting a significant amount of moisture flow through the relatively shallow Paintbrush nonwelded unit, with major faults observed at the site serving as major downward pathways for laterally diverted percolation fluxes. In addition, we used observed field liquid saturation and goechemical isotopic data to check model results and found consistent agreement.

  6. The Pichia pastoris transmembrane protein GT1 is a glycerol transporter and relieves the repression of glycerol on AOX1 expression.

    PubMed

    Zhan, Chunjun; Wang, Songwei; Sun, Yang; Dai, Xiaofeng; Liu, Xiuxia; Harvey, Linda; McNeil, Brian; Yang, Yankun; Bai, Zhonghu

    2016-06-01

    Promoter of alcohol oxidase I (PAOX1) is the most efficient promoter involved in the regulation of recombinant protein expression in Pichia pastoris (P. pastoris). PAOX1 is tightly repressed by the presence of glycerol in the culture medium; thus, glycerol must be exhausted before methanol can be taken up by P. pastoris and the expression of the heterologous protein can be induced. In this study, a candidate glycerol transporter (GT1, GeneID: 8197545) was identified, and its role was confirmed by further studies (e.g. bioinformatics analysis, heterologous complementation in Schizosaccharomyces pombe (S. pombe)). When GT1 is co-expressed with enhanced green fluorescent protein (EGFP), it localizes to the membrane and S. pombe carrying gt1 but not the wild-type strain can grow on medium containing glycerol as the sole carbon source. The present study is the first to report that AOX1 in the X-33Δgt1 mutant can achieve constitutive expression in medium containing glycerol; thus, knocking down gt1 can eliminate the glycerol repression of PAOX1 in P. pastoris These results suggest that the glycerol transporter may participate in the process of PAOX1 inhibition in glycerol medium. PMID:27189360

  7. Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury

    PubMed Central

    Østergaard, Leif; Engedal, Thorbjørn S; Aamand, Rasmus; Mikkelsen, Ronni; Iversen, Nina K; Anzabi, Maryam; Næss-Schmidt, Erhard T; Drasbek, Kim R; Bay, Vibeke; Blicher, Jakob U; Tietze, Anna; Mikkelsen, Irene K; Hansen, Brian; Jespersen, Sune N; Juul, Niels; Sørensen, Jens CH; Rasmussen, Mads

    2014-01-01

    Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of ‘classic' ischemia. We discuss diagnostic and therapeutic consequences of these predictions. PMID:25052556

  8. Induced thermal dynamics in the melt of glycerol and aerosil dispersions.

    PubMed

    Sharma, Dipti; Iannacchione, Germano S

    2007-03-01

    A high-resolution calorimetric spectroscopy study has been performed on pure glycerol and colloidal dispersions of an aerosil gel in glycerol covering a wide range of temperatures from 300 to 380 K, deep in the liquid phase of glycerol. The colloidal glycerol+aerosil samples with 0.07, 0.14, and 0.32 g of silica per cm3 of glycerol reveal activated energy (thermal) dynamics at temperatures well above the Tg of the pure glycerol. The onset of these dynamics appears to be due to the frustration or pinning imposed by the silica gel on the glycerol liquid and is apparently a long-range, cooperative phenomena. Since this behavior begins to manifest itself at relatively low silica densities (large mean void length compared to the size of a glycerol molecule) and speeds up with increasing density, these induced dynamics are likely due to a coupling between the flexible aerosil gel and large groups of glycerol molecules mediated by mutual hydrogen bonding. This is supported by the lack of such thermal dynamics in pure aerosil gels, pure glycerol, or aerosil gels dispersed in a non-glass-forming, non-hydrogen-bonding, liquid crystal under nearly identical experimental conditions. The study of such frustrated colloids may provide a unique avenue for illuminating the physics of glasses. PMID:17362111

  9. Measurement of serum total glycerides and free glycerol by high-performance liquid chromatography.

    PubMed

    Li, Hongxia; Dong, Jun; Chen, Wenxiang; Wang, Shu; Guo, Hanbang; Man, Yong; Mo, Peisheng; Li, Jianzhai

    2006-09-01

    Serum levels of total glycerides and free glycerol are important indices of lipid metabolism and cardiovascular disease risk. Convenient enzymatic methods of measurement have been available, but they are susceptible to interference. Situations exist in both research and clinical laboratories in which more specific and precise methods are needed. We developed HPLC methods for the measurement of serum total glycerides and free glycerol. For total glycerides, serum was mixed with an internal standard (1,2,4-butanetriol) and treated with alcoholic sodium hydroxide to hydrolyze glycerides to glycerol. After deproteinization with tungstic acid, the glycerol was benzoylated with an optimized Schotten-Baumann reaction and analyzed by HPLC. For free glycerol, serum was equilibrated with the internal standard and deproteinized with tungstic acid to remove the glycerides. The glycerol was benzoylated and analyzed as for total glycerol. Various factors were investigated, and no significant sources of interference were detected. The total coefficients of variation ranged from 0.7% to 2.0% for total glycerides and from 1.7% to 3.2% for free glycerol. The analytical recoveries ranged from 98.5% to 101.6%. In conclusion, simple and reliable HPLC methods for serum total glycerides and free glycerol have been developed. The methods may also be used for the analyses of glycerol or glycerides in other biological samples. PMID:16788212

  10. Effect of Glycerol Water Binary Mixtures on the Structure and Dynamics of Protein Solutions

    SciTech Connect

    Ghattyvenkatakrishna, Pavan K; Carri, Gustavo A.

    2014-01-01

    We have performed 20ns of fully atomistic molecular dynamics simulations of Hen Egg-White Lysozyme in 0, 10, 20, 30 and 100% by weight of glycerol in water to better understand the microscopic physics behind the bioprotection offered by glycerol to naturally occuring biological systems. The sovlent exposure of protein surface residues changes when glycerol is introduced. The dynamic behavior of the protein, as quantified by the Incoherent Intermediate Scattering Function, shows a non-monotonic dependence on glycerol content. The fluctuations of the protein residues with respect to each other were found to be similar in all water containing solvents; but different from the pure glycerol case. The increase in the number of protein glycerol hydrogen bonds in glycerol water binary mixtures explains the slowing down of protein dynamics as the glycerol content increases. We also explored the dynamic behavior of the hydration layer. We show that the short-length scale dynamics of this layer are insenstive to glycerol concentration. However, the long-length scale behavior shows a significant dependence on glycerol content. We also provide insights into the behavior of bound and mobile water molecules.

  11. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    DOE PAGESBeta

    Gupta, S.; Arend, N.; Lunkenheimer, P.; Loidl, A.; Stingaciu, L.; Jalarvo, N.; Mamontov, E.; Ohl, M.

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, whichmore » directly couples to density fluctuations.« less

  12. Influence of local capillary trapping on containment system effectiveness

    SciTech Connect

    Bryant, Steven

    2014-03-31

    Immobilization of CO2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence of injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO2 migration can be represented as a single value of “critical capillary entry pressure” Pc,entrycrit, such that cells with capillary entry pressure greater/less than Pc,entrycrit act as barriers/potential traps during CO2 migration. At intermediate values of Pc,entrycrit, the barrier regions become more laterally extensive in the reservoir

  13. Impact of impurities in biodiesel-derived crude glycerol on the fermentation by Clostridium pasteurianum ATCC 6013.

    PubMed

    Venkataramanan, Keerthi P; Boatman, Judy J; Kurniawan, Yogi; Taconi, Katherine A; Bothun, Geoffrey D; Scholz, Carmen

    2012-02-01

    During the production of biodiesel, crude glycerol is produced as a byproduct at 10% (w/w). Clostridium pasteurianum has the inherent potential to grow on glycerol and produce 1,3-propanediol and butanol as the major products. Growth and product yields on crude glycerol were reported to be slower and lower, respectively, in comparison to the results obtained from pure glycerol. In this study, we analyzed the effect of each impurity present in the biodiesel-derived crude glycerol on the growth and metabolism of glycerol by C. pasteurianum. The crude glycerol contains methanol, salts (in the form of potassium chloride or sulfate), and fatty acids that were not transesterified. Salt and methanol were found to have no negative effects on the growth and metabolism of the bacteria on glycerol. The fatty acid with a higher degree of unsaturation, linoleic acid, was found to have strong inhibitory effect on the utilization of glycerol by the bacteria. The fatty acid with lower or no degrees of unsaturation such as stearic and oleic acid were found to be less detrimental to substrate utilization. The removal of fatty acids from crude glycerol by acid precipitation resulted in a fermentation behavior that is comparable to the one on pure glycerol. These results show that the fatty acids in the crude glycerol have a negative effect by directly affecting the utilization of glycerol as the carbon source, and hence their removal from crude glycerol is an essential step towards the utilization of crude glycerol. PMID:22202963

  14. Studies on Freezing RAM Semen in Absence of Glycerol.

    NASA Astrophysics Data System (ADS)

    Abdelnaby, Abdelhady Abdelhakeam

    1988-12-01

    Glycerol is widely used as a major cryoprotective agent for freezing spermatozoa of almost all species. However, it reduces fertility of sheep inseminated cervically compared with intrauterine insemination. Studies were conducted to develop a method and procedure for freezing ram semen in the absence of glycerol. Post -thaw survival of ram spermatozoa frozen in the absence of glycerol was affected by time and temperature after collection and before dilution and time after dilution and before freezing. Increase in time at 5^ circC before or after dilution and before freezing increased both post-thaw motility and number of cells passing through Sephadex filter. A cold dilution method was developed. Slow cooling of fresh ram semen and diluting at 5^circ C 2-3 hr. after collection, then freezing 1 hr. after dilution improved both post-thaw motility and number of cells passing through Sephadex filter compared with immediate dilution at 30-37^circC after collection and freezing 3-4 hr. later (P < 0.05). An extender was developed to freeze ram semen in the absence of glycerol. An increase in post-thaw motility was obtained when semen was extended in TES titrated with Tris to pH 7.0 (TEST) and osmotic pressure of 375-400 mOsm/kg, containing 25-30% (v/v) egg yolk and 10% (v/v) maltose. A special device (boat) for freezing was constructed to insure the same height of the sample above LN _2 and thus the same freezing rate from freeze to freeze. Freezing of semen in 0.25cc straws at 5-10 cm above LN_2 (73.8 to 49.5 ^circC/min) yielded higher post-thaw motility than the rates resulted from freezing at 15 cm above LN_2 or 1 cm above LN _2. Faster Thawing in 37^ circC water for 30 sec. (7.8^ circC/sec.) increased post-thaw motility compared with slower thawing in 5 or 20^circ C water (P < 0.05). A lambing rate of 52.2% was obtained in one fertility trial conducted with ram semen frozen without glycerol and 17.1% in a second trial. One injection (IM) of 15 mg PGF_{2alpha}/ewe for

  15. Methylation and cyclisation of branched glycerol dialkyl glycerol tetraethers as temperature and pH proxies

    NASA Astrophysics Data System (ADS)

    Blaga, C. I.; Reichart, G.-J.; Schouten, S.; Lotter, A.; Sinninghe Damste, J. S.

    2009-04-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) containing 0 to 2 cyclopentyl moieties were initially detected in peat deposits [1]. Through the analysis of a global set of soils samples Weijers et al. [2] showed that these GDGTs, probably of bacterial origin, are produced in situ in these soils. Rivers and direct run-off transport these compounds, together with other soil organic matter, to marine [3] and lake sediments [4, 5]. Recently, Weijers et al. [6] defined two indices that are based on branched GDGTs that are distinctively influenced by two environmental factors. The cyclisation ratio of the branched tetraethers (CBT) is related to soil pH and the methylation index of branched tetraethers (MBT) is related to temperature and soil pH. Lake sediments are often used for reconstructing past climatic changes. The presence of branched GDGTs in lake sediments potentially allows reconstruction of temperature and pH of the lake drainage area. We performed organic geochemical analyses on a series of surface sediments from 82 lakes characterised by variable amounts of soil organic matter and from different geographical locations to establish the application of the MBT/CBT as a continental palaeothermometer. Results show that in all of the 82 lakes substantial amounts of branched GDGTs are present (0.1-28% of total GDGTs). Besides the branched GDGTs crenarchaeol was also found in appreciable amounts (on average 23% of the total GDGTs). In the lakes from the northern hemisphere in fact the dominant GDGT is crenarchaeol (38% of total GDGTs) followed by the pentamethylated branched GDGT. In the southern hemisphere on the other hand we observe the hexamethylated branched GDGT as the dominant GDGT and crenarchaeol is here ten times less abundant then in the north (on average 3% of total GDGTs only). The CBT, as defined by Weijers et al. [6], for the entire data set ranges from values close to 0 (0.14 for Lake Ohrid) to 1.7 (Lake Nyos). The MBT ratio, also as defined

  16. Study and comparison of two enzyme membrane reactors for fatty acids and glycerol production

    SciTech Connect

    Molinari, R.; Santoro, M.E.; Drioli, E. . Dept. of Chemical Engineering and Materials Inst. on Membranes and Chemical Reactors-CNR, Arcavacata di Rende )

    1994-11-01

    Two enzyme membrane reactors (EMR), (1) with one substrate (olive oil) in an oil-in-water emulsion (E-EMR) and (2) with two separated liquid phases (oil and water) (TSLP-EMR), have been studied for the conversion of the triglycerides to fatty acids and glycerol. The enzyme was Candida cylindracea lipase confined on the pressurized face or entrapped in the sponge side of capillary ultrafiltration membranes. Two methods for immobilizing the enzyme in the TSLP-EMR were used: ultrafiltration on a virgin membrane and ultrafiltration on glutaraldehyde pretreated membranes. A multiple use of the reactor was obtained immobilizing the enzyme on the membrane preactivated with glutaraldehyde. The TSLP-EMR showed a specific activity of 0.529 mmol/(mg[center dot]h) versus a specific activity of 0.170 mmol/(mg[center dot]h) of the E-EMR. The rate of fatty acid production in the TSLP-EMR was linear with time showing no enzyme deactivation in an operating time of 80 h. The kinetics observed in the two reactors was different: an equilibrium reaction product-inhibited for the E-EMR and an apparent irreversible reaction of zero order for the TSLP-EMR. Taking into account that in the TSLP-EMR, compared to the E-EMR, (1) the specific activity was higher, (2) the specific rate was constant with the time, and (3) the two products were already separated after the reaction, the TSLP-EMR configuration seems the more convenient.

  17. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    2005-08-09

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

  18. Dielectric and specific heat relaxations in vapor deposited glycerol

    SciTech Connect

    Kasina, A. E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M. E-mail: wubbenhorst@fys.kuleuven.be

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk T{sub g} and subsequent cooling/reheating revealed a step-wise increase in c{sub p} by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at −75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of “MROL glycerol” to its “normal” (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy c{sub p}, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τ{sub cal} from that of normal “bulk” glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the

  19. Geometry of the capillary net in human hearts.

    PubMed

    Rakusan, K; Cicutti, N; Spatenka, J; Samánek, M

    1997-01-01

    The geometry of the coronary capillary bed in human hearts was studied using samples obtained during cardiac surgery of children operated for tetralogy of Fallot and samples from fresh normal hearts used for valve harvesting. The results revealed a similar coronary capillary density and heterogeneity of capillary spacing in samples from both groups. A double-staining method was used to distinguish between capillary segments close to the feeding arteriole (proximal capillaries) and segments distant from the arteriole (distal capillaries). In both groups of hearts, capillary segment length was consistently shorter on the venular than the arteriolar portion of the capillary. Similarly, capillary domain areas were also smaller and the resulting capillary supply unit was smaller along venular portions compared to arteriolar regions of the capillary bed. This distinctive geometry would provide advantageous geometric conditions for tissue oxygen supply. PMID:9176723

  20. Accelerated immunoassays based on magnetic particle dynamics in a rotating capillary tube with stationary magnetic field

    PubMed Central

    Lee, Jun-Tae; Sudheendra, L.; Kennedy, Ian M.

    2012-01-01

    A rapid and simple magnetic particle-based immunoassay has been demonstrated in a capillary mixing system. Antibody-coated micrometer size super-paramagnetic polystyrene (SPP) particles were used in an assay for rabbit IgG in a sandwich (non-competitive) format. The kinetics of the assay was compared between a plate – based system and a single capillary tube. The interaction between the antigen (R-IgG) and the antibody (anti-R-IgG) that was carried by the SPP particles in a rotating capillary was tested under a stationary magnetic field. Competing magnetic and viscous drag forces helped to enhance the interaction between the analyte and the capture antibodies on the particles. The dimensionless Mason number (Mn) was employed to characterize the magnetic particle dynamics – a previously determined critical Mason number (Mnc) was employed as a guide to the appropriate experimental conditions of magnetic field strength and rotational speed of the capillary. The advantage of the rotating capillary system included a short assay time and a reduced reactive volume (20μl). The results show that the immunoassay kinetics were improved by the formation of chains of the SPP particles for the conditions that corresponded to the critical Mason number. PMID:22931580

  1. Towards new applications using capillary waveguides

    PubMed Central

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N.; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-01-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  2. Towards new applications using capillary waveguides.

    PubMed

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-12-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 μm-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 μm-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 μm beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  3. Measurement of the chondrocyte membrane permeability to Me2SO, glycerol and 1,2-propanediol.

    PubMed

    Xu, Xia; Cui, Zhanfeng; Urban, Jill P G

    2003-09-01

    The addition of cryopreservative agents (CPAs) to chondrocytes and natural and engineered cartilage is critical to protect the cells and tissues from freezing damage during cryopreservation, but this may cause cell damage, e.g. by osmotic shock. The damage could be minimized by the control of the cell volume excursion with the knowledge of cell membrane permeability. In this study, the cell volume responses of chondrocytes to three commonly used CPAs were evaluated using a perfusion microscope stage. The osmotic response of chondrocytes was measured to the perfusion with 1.4 M dimethyl sulfoxide (Me2SO), 1,2-propanediol and glycerol at 21 degrees C. Cell volumes and their transients were determined with image analysis. The cell membrane permeability parameters, including the hydraulic conductivity (Lp), the CPA permeability (omega) and the reflection coefficients (sigma) in the Kedem-Katchalsky (K-K) model, and the Lp and omega in the two-parameter model were determined. The correlated K-K parameters at 21 degrees C were Lp=0.166 +/- 0.035, 0.149 +/- 0.061, 0.212 +/- 0.041 microm/min atm, omega=(7.630 +/- 0.174) x 10(-2), (1.428 +/- 0.627) x 10(-2), (2.744 +/- 0.775) x 10(-2) microm/s and sigma=0.91 +/- 0.09, 0.82 +/- 0.11, 0.88 +/- 0.10 for Me(2)SO, glycerol and 1,2-propanediol, respectively. For the two-parameter model, the parameter values were Lp=0.163 +/- 0.040, 0.128 +/- 0.031, 0.169 +/- 0.025 microm/min atm, omega=(7.881 +/- 0.178) x 10(-2), (1.529 +/- 0.525) x 10(-2), (3.716 +/- 0.493) x 10(-2) microm/s for Me2SO, glycerol and 1,2-propanediol, respectively. No significant difference in the predictions of cell volume excursion during CPA addition was observed when using either the K-K model or the two-parameter model and it was hence advised to adopt the simple two-parameter model in the evaluation. The measured parameters can be used to optimise the CPA addition and removal protocols to maximize the cell survival during cryopreservation. PMID:12835070

  4. Electron beam irradiation of maltodextrin and cinnamyl alcohol mixtures: influence of glycerol on cross-linking.

    PubMed

    Khandal, Dhriti; Aggarwal, Manjeet; Suri, Gunjan; Coqueret, Xavier

    2015-03-01

    The influence of glycerol on the electron beam-induced changes in maltodextrins-cinnamyl alcohol (CA) blends is examined with respect to its influence on the degree of chain scission, grafting, and cross-linking. The study is relevant to radiation-induced polysaccharide modification, specifically in the perspective of using blended starch as a thermoplastic material, where glycerol is commonly used as a plasticizer. In the absence of CA, glycerol protects maltodextrin from chromophore formation onto the main chain, but also induces more chain scission. The presence of CA provides efficient radiation-protection against scission. Glycerol is shown to affect the interaction between maltodextrin and CA, most likely in the form of an inclusion complex when glycerol is absent. The global behavior under radiation is therefore governed by the physical interactions between the blend constituents rather than on the role of glycerol role as a plasticizer, or as an OH˙ radical scavenger. PMID:25498620

  5. Co-gasification of hardwood chips and crude glycerol in a pilot scale downdraft gasifier.

    PubMed

    Wei, Lin; Pordesimo, Lester O; Haryanto, Agus; Wooten, James

    2011-05-01

    Seeking appropriate approaches to utilize the crude glycerol produced in biodiesel production is very important for the economic viability and environmental impacts of biodiesel industry. Gasification may be one of options for addressing this issue. Co-gasification of hardwood chips blending with crude glycerol in various loading levels was undertaken in the study involving a pilot scale fixed-bed downdraft gasifier. The results indicated that crude glycerol loading levels affected the gasifier's performance and the quality of syngas produced. When crude glycerol loading level increased, the CO, CH(4), and tar concentrations of the syngas also increased but particle concentration decreased. Though further testing is suggested, downdraft gasifiers could be run well with hardwood chips blending with liquid crude glycerol up to 20 (wt%). The syngas produced had relatively good quality for fueling internal combustion engines. This study provides a considerable way to utilize crude glycerol. PMID:21435871

  6. Bioconversion of glycerol for bioethanol production using isolated Escherichia coli ss1

    PubMed Central

    Suhaimi, Sheril Norliana; Phang, Lai-Yee; Maeda, Toshinari; Abd-Aziz, Suraini; Wakisaka, Minato; Shirai, Yoshihito; Hassan, Mohd Ali

    2012-01-01

    Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production. PMID:24031858

  7. Value-added processing of crude glycerol into chemicals and polymers.

    PubMed

    Luo, Xiaolan; Ge, Xumeng; Cui, Shaoqing; Li, Yebo

    2016-09-01

    Crude glycerol is a low-value byproduct which is primarily obtained from the biodiesel production process. Its composition is significantly different from that of pure glycerol. Crude glycerol usually contains various impurities, such as water, methanol, soap, fatty acids, and fatty acid methyl esters. Considerable efforts have been devoted to finding applications for converting crude glycerol into high-value products, such as biofuels, chemicals, polymers, and animal feed, to improve the economic viability of the biodiesel industry and overcome environmental challenges associated with crude glycerol disposal. This article reviews recent advances of biological and chemical technologies for value-added processing of crude glycerol into chemicals and polymers, and provides strategies for addressing production challenges. PMID:27004448

  8. Rheological properties of purified illite clays in glycerol/water suspensions

    NASA Astrophysics Data System (ADS)

    Dusenkova, I.; Malers, J.; Berzina-Cimdina, L.

    2015-04-01

    There are many studies about rheological properties of clay-water suspensions, but no published investigations about clay-glycerol suspensions. In this work apparent viscosity of previously purified illite containing clay fraction < 2 μm and glycerol/water suspensions were investigated. Carbonates were removed by dissolution in hydrochloric and citric acids and other non-clay minerals were almost totally removed by centrifugation. All obtained suspensions behaved as shear-thinning fluids with multiple times higher viscosity than pure glycerol/water solutions. Reduction of clay fraction concentration by 5% decreased the apparent viscosity of 50% glycerol/water suspensions approximately 5 times. There was basically no difference in apparent viscosity between all four 50% glycerol/water suspensions, but in 90% glycerol/water suspensions samples from Iecava deposit showed slightly higher apparent viscosity, which could be affected by the particle size distribution.

  9. Evaporation dynamics of femtoliter water capillary bridges

    NASA Astrophysics Data System (ADS)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Kim, Jung Gu; Weon, Byung Mook

    2015-11-01

    Capillary bridges are usually formed by a small liquid volume in confined space between two solid surfaces and particularly they have lower internal pressure than 1 atm at femtoliter scales. Femtoliter capillary bridges exhibit rapid evaporation rates. To quantify detailed evaporation kinetics of femtoliter bridges, we present a feasible protocol to directly visualize femtoliter water bridges that evaporate in still air between a microsphere and a flat substrate by utilizing transmission X-ray microscopy. Precise measurements of evaporation kinetics for water bridges indicate that lower water pressure than 1 atm can significantly decelerate evaporation by suppression of vapor diffusion. This finding would provide a consensus to understand evaporation of ultrasmall capillary bridges.

  10. Arrested segregative phase separation in capillary tubes.

    PubMed

    Tromp, R Hans; Lindhoud, Saskia

    2006-09-01

    Phase separation in a capillary tube with one of the phases fully wetting the capillary wall is arrested when the typical size of the phase domains reaches the value of the diameter of the tube. The arrested state consists of an alternating sequence of concave-capped and convex-capped cylindrical domains, called "plugs," "bridges," or "lenses," of wetting and nonwetting phase, respectively. A description of this arrested plug state for an aqueous mixture of two polymer solutions is the subject of this work. A phase separating system consisting of two incompatible polymers dissolved in water was studied. The phase volume ratio was close to unity. The initial state from which plugs evolve is characterized by droplets of wetting phase in a continuous nonwetting phase. Experiments show the formation of plugs by a pathway that differs from the theoretically well-described instabilities in the thickness of a fluid thread inside a confined fluid cylinder. Plugs appear to form after the wetting layer (the confined fluid cylinder) has become unstable after merging of droplet with the wetting layer. The relative density of the phases could be set by the addition of salt, enabling density matching. As a consequence, the capillary length can in principle be made infinitely large and the Bond number (which represents the force of gravity relative to the capillary force) zero, without considerably changing the interfacial tension. Using the possibility of density matching, the relations among capillary length and capillary diameter on the one hand, and the presence of plugs and their average size on the other were studied. It was found that stable plugs are present when the capillary radius does not exceed a certain value, which is probably smaller than the capillary length. However, the average plug size is independent of capillary length. At constant capillary length, average plug size was found to scale with the capillary diameter to a power 1.3, significantly higher than the

  11. 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

  12. Micromechanism linear actuator with capillary force sealing

    DOEpatents

    Sniegowski, Jeffry J.

    1997-01-01

    A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.

  13. Quantitative analysis of glycerol in dicarboxylic acid-rich cutins provides insights into Arabidopsis cutin structure.

    PubMed

    Yang, Weili; Pollard, Mike; Li-Beisson, Yonghua; Ohlrogge, John

    2016-10-01

    Cutin is an extracellular lipid polymer that contributes to protective cuticle barrier functions against biotic and abiotic stresses in land plants. Glycerol has been reported as a component of cutin, contributing up to 14% by weight of total released monomers. Previous studies using partial hydrolysis of cuticle-enriched preparations established the presence of oligomers with glycerol-aliphatic ester links. Furthermore, glycerol-3-phosphate 2-O-acyltransferases (sn-2-GPATs) are essential for cutin biosynthesis. However, precise roles of glycerol in cutin assembly and structure remain uncertain. Here, a stable isotope-dilution assay was developed for the quantitative analysis of glycerol by GC/MS of triacetin with simultaneous determination of aliphatic monomers. To provide clues about the role of glycerol in dicarboxylic acid (DCA)-rich cutins, this methodology was applied to compare wild-type (WT) Arabidopsis cutin with a series of mutants that are defective in cutin synthesis. The molar ratio of glycerol to total DCAs in WT cutins was 2:1. Even when allowing for a small additional contribution from hydroxy fatty acids, this is a substantially higher glycerol to aliphatic monomer ratio than previously reported for any cutin. Glycerol content was strongly reduced in both stem and leaf cutin from all Arabidopsis mutants analyzed (gpat4/gpat8, att1-2 and lacs2-3). In addition, the molar reduction of glycerol was proportional to the molar reduction of total DCAs. These results suggest "glycerol-DCA-glycerol" may be the dominant motif in DCA-rich cutins. The ramifications and caveats for this hypothesis are presented. PMID:27211345

  14. Thermal Transitions and Extrusion of Glycerol-Plasticized Whey Protein Mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of glycerol and moisture contents on the thermal transitions of whey protein isolate (WPI) powder-glycerol-water mixtures were studied. Mixtures with ratios of 100:0, 70:30, 60:40 and 50:50 WPI:glycerol on a dry basis (db) were pre-conditioned to 0.34+/-0.01 (25.4±0.4ºC) and 0.48+/-0.02...

  15. Anaerobic fermentation of glycerol in Paenibacillus macerans: metabolic pathways and environmental determinants.

    PubMed

    Gupta, Ashutosh; Murarka, Abhishek; Campbell, Paul; Gonzalez, Ramon

    2009-09-01

    Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paenibacillus, able to ferment hexoses, deoxyhexoses, pentoses, cellulose, and hemicellulose. However, little is known about glycerol metabolism in this organism, and some studies have reported that glycerol is not fermented. Despite these reports, we found that several P. macerans strains are capable of anaerobic fermentation of glycerol. One of these strains, P. macerans N234A, grew fermentatively on glycerol at a maximum specific growth rate of 0.40 h(-1) and was chosen for further characterization. The use of [U-13C]glycerol and further analysis of extracellular metabolites and proteinogenic amino acids via nuclear magnetic resonance (NMR) spectroscopy allowed identification of ethanol, formate, acetate, succinate, and 1,2-propanediol (1,2-PDO) as fermentation products and demonstrated that glycerol is incorporated into cellular components. A medium formulation with low concentrations of potassium and phosphate, cultivation at acidic pH, and the use of a CO2-enriched atmosphere stimulated glycerol fermentation and are proposed to be environmental determinants of this process. The pathways involved in glycerol utilization and synthesis of fermentation products were identified using NMR spectroscopy in combination with enzyme assays. Based on these studies, the synthesis of ethanol and 1,2-PDO is proposed to be a metabolic determinant of glycerol fermentation in P. macerans N234A. Conversion of glycerol to ethanol fulfills energy requirements by generating one molecule of ATP per molecule of ethanol synthesized. Conversion of glycerol to 1,2-PDO results in the consumption of reducing equivalents, thus facilitating redox balance. Given the availability, low price, and high degree of reduction of glycerol, the high metabolic rates exhibited by P. macerans N234A are of paramount importance for the production of fuels and chemicals. PMID:19617389

  16. Calcification in bleached and unbleached Montastraea faveolata: evaluating the role of oxygen and glycerol

    NASA Astrophysics Data System (ADS)

    Colombo-Pallotta, M. F.; Rodríguez-Román, A.; Iglesias-Prieto, R.

    2010-12-01

    All reef-building corals are symbiotic with dinoflagellates of the genus Symbiodinium, which influences many aspects of the host’s physiology including calcification. Coral calcification is a biologically controlled process performed by the host that takes place several membranes away from the site of photosynthesis performed by the symbiont. Although it is well established that light accelerates CaCO3 deposition in reef-building corals (commonly referred to as light-enhanced calcification), the complete physiological mechanism behind the process is not fully understood. To better comprehend the coral calcification process, a series of laboratory experiments were conducted in the major Caribbean reef-building species Montastraea faveolata, to evaluate the effect of glycerol addition and/or the super-saturation of oxygen in the seawater. These manipulations were performed in bleached and unbleached corals, to separate the effect of photosynthesis from calcification. The results suggest that under normal physiological conditions, a 42% increase in seawater oxygen concentration promotes a twofold increase in dark-calcification rates relative to controls. On the other hand, the results obtained using bleached corals suggest that glycerol is required, as a metabolic fuel, in addition to an oxygenic environment in a symbiosis that has been disrupted. Also, respiration rates in symbiotic corals that were pre-incubated in light conditions showed a kinetic limitation, whereas corals that were pre-incubated in darkness were oxygen limited, clearly emphasizing the role of oxygen in this regard. These findings indicate that calcification in symbiotic corals is not strictly a “light-enhanced” or “dark-repressed” process, but rather, the products of photosynthesis have a critical role in calcification, which should be viewed as a “photosynthesis-driven” process. The results presented here are discussed in the context of the current knowledge of the coral

  17. "Getting the best sensitivity from on-capillary fluorescence detection in capillary electrophoresis" - A tutorial.

    PubMed

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2016-09-01

    Capillary electrophoresis with Laser-Induced Fluorescence (CE-LIF) detection is being applied to new analytical problems which challenge both the power of CE separation and the sensitivity of LIF detection. On-capillary LIF detection is much more practical than post-capillary detection in a sheath-flow cell. Therefore, commercial CE instruments utilize solely on-capillary CE-LIF detection with a Limit of Detection (LOD) in the nM range, while there are multiple applications of CE-LIF that require pM or lower LODs. This tutorial analyzes all aspects of on-capillary LIF detection in CE in an attempt to identify means for improving LOD of CE-LIF with on-capillary detection. We consider principles of signal enhancement and noise reduction, as well as relevant areas of fluorophore photochemistry and fluorescent microscopy. PMID:27543015

  18. Evaluation of optical clearing with the combined liquid paraffin and glycerol mixture

    PubMed Central

    Wang, Jingyi; Liang, Yanmei; Zhang, Shu; Zhou, Yueqiao; Ni, Haiyang; Li, Yan

    2011-01-01

    By scanning biological tissues in vivo and in vitro with optical coherence tomography, it is found that liquid paraffin can enhance the percutaneous penetration of glycerol in deep layers of tissue and take synergistically optical clearing effect with glycerol. It is shown from experimental results that 30% - 50% liquid paraffin glycerol solutions have the best enhancement effect. Considering the refractive index of liquid paraffin and its medicinal value, we think liquid paraffin will play an important role in optical clearing as the penetration enhancer of glycerol in future clinical research. PMID:21833369

  19. The glycerol teichoic acid from the cell wall of Bacillus stearothermophilus B65

    PubMed Central

    Wicken, A. J.

    1966-01-01

    1. A glycerol teichoic acid has been extracted from cell walls of Bacillus stearothermophilus B65 and its structure examined. 2. Trichloroacetic acid-extractable teichoic acid accounted for 68% of the total cell-wall phosphorus and residual material could be hydrolysed to a mixture of products including those characteristic of glycerol teichoic acids. 3. The extracted polymer is composed of glycerol, phosphoric acid, d-glucose and d-alanine. 4. Hydrolysis of the polymer with alkali gave glycerol, 1-O-α-d-glucopyranosylglycerol and its monophosphates, glycerol mono- and di-phosphate, as well as traces of a glucosyldiglycerol triphosphate and a glucosylglycerol diphosphate. 5. The teichoic acid is a polymer of 18 or 19 glycerol phosphate units having α-d-glucopyranosyl residues attached to position 1 of 14 or 15 of the glycerol residues. 6. The glycerol residues are joined by phosphodiester linkages involving positions 2 and 3 in each glycerol. 7. d-Alanine is in ester linkage to the hydroxyl group at position 6 of approximately half of the glucose residues. 8. One in every 13 or 12 polymer molecules bears a phosphomonoester group on position 3 of a glucose residue, the possible significance of which in linkage of the polymer to other wall constituents is discussed. PMID:4290549

  20. Characteristics of droplets ejected from liquid glycerol doped with carbon in laser ablation propulsion

    NASA Astrophysics Data System (ADS)

    Zhi-Yuan, Zheng; Si-Qi, Zhang; Tian, Liang; Lu, Gao; Hua, Gao; Zi-Li, Zhang

    2016-04-01

    The characteristics of droplets ejected from liquid glycerol doped with carbon are investigated in laser ablation propulsion. Results show that carbon content has an effect on both the coupling coefficient and the specific impulse. The doped-carbon moves the laser focal position from the glycerol interior to the surface. This results in a less consumed glycerol and a high specific impulse. An optimal propulsion can be realized by varying carbon content in glycerol. Project supported by the National Natural Science Foundation of China (Grant No. 10905049) and the Fundamental Research Funds for the Central Universities, China (Grant Nos. 53200859165 and 2562010050).

  1. Mechanistic investigation of ultrasonic enhancement of glycerol bioconversion by immobilized Clostridium pasteurianum on silica support.

    PubMed

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2013-06-01

    Glycerol, the principal byproduct of biodiesel production, can be a valuable carbon source for bioconversion into diverse class of compounds. This article attempts to investigate the mechanistic aspects of ultrasound mediated bioconversion of glycerol to ethanol and 1,3-propanediol (1,3-PDO) by immobilized Clostridium pasteurianum cells on silica support. Our approach is of coupling experimental results with simulations of cavitation bubble dynamics and enzyme kinetics. In addition, the statistical analysis (ANOVA) of experimental results was also done. The glycerol uptake by cells was not affected by either immobilization or with ultrasonication. Nonetheless, both immobilization and ultrasonication were found to enhance glycerol consumption. The enhancement effect of ultrasound on glycerol consumption was most marked (175%) at the highest glycerol concentration of 25 g/L (271.7 mM). The highest glycerol consumption (32.4 mM) was seen for 10 g/L (108.7 mM) initial glycerol concentration. The immobilization of cells shifted the metabolic pathway almost completely towards 1,3-PDO. No formation of ethanol was seen with mechanical shaking, while traces of ethanol were detected with ultrasonication. On the basis of analysis of enzyme kinetics parameters, we attribute these results to increased substrate-enzyme affinity and decreased substrate inhibition for 1,3-PDO dehydrogenase in presence of ultrasound that resulted in preferential conversion of glycerol into 1,3-PDO. PMID:23322632

  2. Dynamic shear modulus of glycerol: Corrections due to instrument compliance

    NASA Astrophysics Data System (ADS)

    Schröter, K.; Hutcheson, S. A.; Shi, X.; Mandanici, A.; McKenna, G. B.

    2006-12-01

    A recent article by Shi et al. [J. Chem. Phys.123, 174507 (2005)] reports results from mechanical measurements on three simple inorganic glass formers: glycerol, m-toluidine, and sucrose benzoate. The experiments carried out were stress relaxation, aging, and dynamic (all in shear) using a torsional rheometer, an advanced rheometric expansion system (TA Instruments). The original force rebalance transducer (2KFRT) supplied with the system was replaced with a custom-made load cell (Sensotec) that had a capacity of 20000gcm in torque and 5000g in normal force. The replacement of the load cell was done due to the belief that the main source of compliance in this instrument was from the 2KFRT. With this assumption, the authors published their results for the three materials of interest and compared their results with the techniques of Schröter and Donth [J. Chem. Phys.113, 9101 (2000)] for the measurements on glycerol and reported important differences. These differences were disputed by one of the present authors (Schröter), and the present report shows that the results from Schröter and Donth are correct. We show that the reasons have to do with the instrument compliance being greater than originally thought by Shi et al. Here we examine the effects of platen diameter/geometry on the glycerol dynamic moduli, describe a means to correct dynamic data, present a revised comparison of the corrected data with that of Schröter and Donth, and provide a discussion of future work and conclusions.

  3. Glycerol effects on protein flexibility: a tryptophan phosphorescence study.

    PubMed Central

    Gonnelli, M.; Strambini, G. B.

    1993-01-01

    In exploring the dynamic properties of protein structure, numerous studies have focussed on the dependence of structural fluctuations on solvent viscosity, but the emerging picture is still not well defined. Exploiting the sensitivity of the phosphorescence lifetime of tryptophan to the viscosity of its environment we have used the delayed emission as an intrinsic probe of protein flexibility and investigated the effects of glycerol as a viscogenic cosolvent. The phosphorescence lifetime of alcohol dehydrogenase, alkaline phosphatase, apoazurin and RNase T1, as a function of glycerol concentration was studied at various temperatures. Flexibility data, which refer to rather rigid sites of the globular structures, point out that, for some concentration ranges glycerol, effects on the rate of structural fluctuations of alcohol dehydrogenase and RNase T1 do not obey Kramers' a power law on solvent viscosity and emphasize that cosolvent-induced structural changes can be important, even for inner cores of the macromolecule. When the data is analyzed in terms of Kramers' model, for the temperature range 0-30 degrees C one derives frictional coefficients that are relatively large (0.6-0.7) for RNase T1, where the probe is in a flexible region near the surface of the macromolecule and much smaller, less than 0.2, for the rigid sites of the other proteins. For the latter sites the frictional coefficient rises sharply between 40 and 60 degrees C, and its value correlates weakly with molecular parameters such as the depth of burial or the rigidity of a particular site. For RNase T1, coupling to solvent viscosity increases at subzero temperatures, with the coefficient becoming as large as 1 at -20 degrees C. Temperature effects were interpreted by proposing that solvent damping of internal protein motions is particularly effective for low frequency, large amplitude, structural fluctuations yielding highly flexible conformers of the macromolecule. PMID:8369422

  4. Pre-exercise glycerol hydration improves cycling endurance time

    NASA Technical Reports Server (NTRS)

    Montner, P.; Stark, D. M.; Riedesel, M. L.; Murata, G.; Robergs, R.; Timms, M.; Chick, T. W.

    1996-01-01

    The effects of glycerol ingestion (GEH) on hydration and subsequent cycle ergometer submaximal load exercise were examined in well conditioned subjects. We hypothesized that GEH would reduce physiologic strain and increase endurance. The purpose of Study I (n = 11) was to determine if pre-exercise GEH (1.2 gm/kg glycerol in 26 ml/kg solution) compared to pre-exercise placebo hydration (PH) (26 ml/kg of aspartame flavored water) lowered heart rate (HR), lowered rectal temperature (Tc), and prolonged endurance time (ET) during submaximal load cycle ergometry. The purpose of Study II (n = 7) was to determine if the same pre-exercise regimen followed by carbohydrate oral replacement solution (ORS) during exercise also lowered HR, Tc, and prolonged ET. Both studies were double-blind, randomized, crossover trials, performed at an ambient temperature of 23.5-24.5 degrees C, and humidity of 25-27%. Mean HR was lower by 2.8 +/- 0.4 beats/min (p = 0.05) after GEH in Study I and by 4.4 +/- 1.1 beats/min (p = 0.01) in Study II. Endurance time was prolonged after GEH in Study I (93.8 +/- 14 min vs. 77.4 +/- 9 min, p = 0.049) and in Study II (123.4 +/- 17 min vs. 99.0 +/- 11 min, p = 0.03). Rectal temperature did not differ between hydration regimens in both Study I and Study II. Thus, pre-exercise glycerol-enhanced hyperhydration lowers HR and prolongs ET even when combined with ORS during exercise. The regimens tested in this study could potentially be adapted for endurance activities.

  5. [Propagation of autowaves in capillaries thick with moving viscous excitable medium].

    PubMed

    Davydov, V A; Davydov, N V

    2015-01-01

    We consider the propagation of autowaves in the moving liquid excitable medium. The shapes of the autowave fronts in cases of the Poiseuille and Couette flows are determined in flat capillaries within a kinematic approach. We show the existence of a critical velocity for the flows above which the autowave fronts should break off. The possibility of a diode effect--the one-way capillary conductivity--is studied. The results of computer simulations are in good agreement with the theoretical predictions. PMID:26016030

  6. Production of d-Mannitol and Glycerol by Yeasts

    PubMed Central

    Onishi, Hiroshi; Suzuki, Toshiyuki

    1968-01-01

    D-Mannitol has not so far been known as a major product of sugar metabolism by yeasts. Three yeast strains, a newly isolated yeast from soy-sauce mash, Torulopsis versatilis, and T. anomala, were found to be good mannitol producers. Under optimal conditions, the isolate produced mannitol at good yield of 30% of the sugar consumed. Glucose, fructose, mannose, galactose, maltose, glycerol, and xylitol were suitable substrates for mannitol formation. High concentrations of yeast extract, Casamino Acids, NaCl, and KCl in media affected significantly the mannitol yield, whereas high levels of inorganic phosphate did not show any detrimental effect. PMID:5749751

  7. Scattering of water from the glycerol liquid-vacuum interface

    NASA Technical Reports Server (NTRS)

    Benjamin, I.; Wilson, M. A.; Pohorille, A.; Nathanson, G. M.

    1995-01-01

    Molecular dynamics calculations of the scattering of D2O from the glycerol surface at different collision energies are reported. The results for the trapping probabilities and energy transfer are in good agreement with experiments. The calculations demonstrate that the strong attractive forces between these two strongly hydrogen bonding molecules have only a minor effect on the initial collision dynamics. The trapping probability is influenced to a significant extent by the repulsive hard sphere-like initial encounter with the corrugated surface and, only at a later stage, by the efficiency of energy flow in the multiple interactions between the water and the surface molecules.

  8. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  9. ISS Update: Capillary Flow Experiments-2

    NASA Video Gallery

    NASA Public Affairs Officer Kelly Humphries interviews Dr. Mark Weislogel, Principal Investigator for the Capillary Flow Experiments-2 (CFE), from the Portland State University in Oregon. The CFE i...

  10. Capillary Optics generate stronger X-rays

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA scientist, in the Space Sciences lab at Marshall, works with capillary optics that generate more intense X-rays than conventional sources. This capability is useful in studying the structure of important proteins.

  11. Suppressed conductometric capillary electrophoresis separation systems

    SciTech Connect

    Dasgupta, P.K.; Bao, L. )

    1993-04-15

    A tubular cation-exchange membrane is installed at the end of a 60-cm-long 75-[mu]m-bore fused-silica capillary. A static dilute acid regenerant solution surrounds the membranes that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerant solution grounded, effective suppression of electrolytes such as solutions of alkalic metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 10--20 [mu]g/L range for a variety of anions; a typical separation requires 15 min. Applicability to a variety of real samples is demonstrated. 26 refs., 10 figs.

  12. Capillary electrochromatography using fibers as stationary phases.

    PubMed

    Jinno, K; Watanabe, H; Saito, Y; Takeichi, T

    2001-10-01

    Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method. PMID:11669512

  13. CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS

    EPA Science Inventory

    The electrophoretic behavior of bensulfuron Me, sulfometuron Me, nicosulfuron (Accent), chlorimuron Et, thifensulfuron Me (Harmony), metsulfuron Me, and chlorsulfuron was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditio...

  14. Water exclusion from tunnel cavities in the saturated capillary fringe

    NASA Astrophysics Data System (ADS)

    Youngs, E. G.; Kacimov, A. R.; Obnosov, Yu. V.

    2004-03-01

    The problem of water flow around a tunnel cavity located in the saturated capillary fringe on top of a very permeable, freely draining substratum is considered for the critical non-leakage condition when there is uniform vertical downward flow through the upper surface of the saturated region. In this critical condition the soil-water pressure is equal to zero everywhere on the cavity wall that is also a streamline. The conditions at the upper fringe boundary are that the soil-water pressure is equal to the air-entry value of the soil and the flux through this surface is the uniform infiltration rate. The cavity surface and the fringe boundary which is elevated above the cavity position, are found through conformal mapping and the use of integral representations of non-standard mixed boundary-value problems. They are calculated for a range of infiltration rates and compared with those obtained by assuming the upper fringe boundary to be horizontal. The exact analysis given here gives larger tunnel cavities than those given by the approximate treatment of the problem. The results have application in the design of underground repositories against entry of seepage water, the construction of protective capillary barriers and in the design of interceptor drainage systems.

  15. Distributions of glycerol dialkyl glycerol tetraethers in surface soils of Qinghai-Tibetan Plateau: implications of GDGT-based proxies in cold and dry regions

    NASA Astrophysics Data System (ADS)

    Ding, S.; Xu, Y.; Wang, Y.; He, Y.; Hou, J.; Chen, L.; He, J.-S.

    2015-01-01

    The methylation index of branched tetraethers (MBT) and cyclization ratio of branched tetraethers (CBT) based on the distribution of bacteria-derived branched glycerol dialkyl glycerol tetraethers (bGDGTs) are useful proxies for the reconstruction of continental paleotemperature and soil pH. Several calibrations of the MBT-CBT index have been proposed based on global and regional soils and lake sediments. However, little is known about the distribution and applicability of GDGTs proxies in the Qinghai-Tibet Plateau (QTP), a critical region of the global climate system. Here, we investigated 33 surface soils covering a large area of the QTP. Redundancy analysis showed that soil pH was the most important factor affecting GDGT distributions, followed by mean annual precipitation (MAP) and mean annual air temperature (MAT). The branched-isoprenoid tetraether (BIT) index, an indicator for estimation of soil organic matter in aquatic environments, varied from 0.48 to 1 and negatively correlated with soil pH (r2 = 0.38), suggesting that the BIT index should be used with caution in the QTP. A transfer function of the CBT index-soil pH was established to estimate paleo-soil pH in the QTP: pH = 8.33-1.43 × CBT (r2 = 0.80, RMSE = 0.27 pH unit). The local calibration of MBT-CBT index presented a weak, still significant correlation with MAT (r2 = 0.36) mainly owing to the additional influence of MAP (r2 = 0.50). Combining our data with previously reported GDGTs for Chinese soils resulted in a new calibration of MBT/CBT-MAT: MAT = 2.68+26.14 × MBT-3.37 × CBT (r2 = 0.73; RMSE = 4.2 °C, n = 164). The correlation coefficient and residual error of this new transfer function is comparable with global calibrations, suggesting that MBT-CBT paleotemperature proxy is still valid in the QTP.

  16. Capillary Movement in Substrates in Microgravity

    NASA Technical Reports Server (NTRS)

    Bula, R. J.; Duffie, N. A.

    1996-01-01

    A more complete understanding of the dynamics of capillary flow through an unsaturated porous medium would be useful for a number of space and terrestrial applications. Knowledge of capillary migration of liquids in granular beds in microgravity would significantly enhance the development and understanding of how a matrix based nutrient delivery system for the growth of plants would function in a microgravity environment. Thus, such information is of interest from the theoretical as well as practical point of view.

  17. Metabolomic analysis reveals hepatic metabolite perturbations in citrin/mitochondrial glycerol-3-phosphate dehydrogenase double-knockout mice, a model of human citrin deficiency.

    PubMed

    Saheki, Takeyori; Inoue, Kanako; Ono, Hiromi; Tushima, Anmi; Katsura, Natsumi; Yokogawa, Mana; Yoshidumi, Yukari; Kuhara, Tomiko; Ohse, Morimasa; Eto, Kazuhiro; Kadowaki, Takashi; Sinasac, David S; Kobayashi, Keiko

    2011-12-01

    The citrin/mitochondrial glycerol-3-phosphate dehydrogenase (mGPD) double-knockout mouse displays phenotypic attributes of both neonatal intrahepatic cholestasis and adult-onset type II citrullinemia, making it a suitable model of human citrin deficiency. In the present study, we investigated metabolic disturbances in the livers of wild-type, citrin (Ctrn) knockout, mGPD knockout, and Ctrn/mGPD double-knockout mice following oral sucrose versus saline administration using metabolomic approaches. By using gas chromatography/mass spectrometry and capillary electrophoresis/mass spectrometry, we found three general groupings of metabolite changes in the livers of the double-knockout mice following sucrose administration that were subsequently confirmed using liquid chromatography/mass spectrometry or enzymatic methods: a marked increase of hepatic glycerol 3-phosphate, a generalized decrease of hepatic tricarboxylic acid cycle intermediates, and alterations of hepatic amino acid levels related to the urea cycle or lysine catabolism including marked increases in citrulline and lysine. Furthermore, concurrent oral administration of sodium pyruvate with sucrose ameliorated the hyperammonemia induced by sucrose, as had been shown previously, as well as almost completely normalizing the hepatic metabolite perturbations found. Overall, we have identified additional metabolic disturbances in double-KO mice following oral sucrose administration, and provided further evidence for the therapeutic use of sodium pyruvate in our mouse model of citrin deficiency. PMID:21908222

  18. DNA Sequencing by Capillary Electrophoresis

    PubMed Central

    Karger, Barry L.; Guttman, Andras

    2009-01-01

    Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA sequencing methods have evolved from the labor intensive slab gel electrophoresis, through automated multicapillary electrophoresis systems using fluorophore labeling with multispectral imaging, to the “next generation” technologies of cyclic array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes was only possible by the advent of modern sequencing technologies that was a result of step by step advances with a contribution of academics, medical personnel and instrument companies. While next generation sequencing is moving ahead at break-neck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of capillary electrophoresis in DNA sequencing based in part of several of our articles in this journal. PMID:19517496

  19. 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

  20. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, N.J.; Zhang, J.Z.

    1996-10-22

    A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

  1. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    1996-01-01

    A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

  2. Unexpected surface chemistry in capillaries for electrophoresis.

    PubMed

    Kaupp, S; Bubert, H; Baur, L; Nelson, G; Wätzig, H

    2000-10-13

    Good and reproducible capillary quality is needed to develop robust methods and to facilitate method transfer in CE. Physical surface defects no longer play a major role in variability of fused-silica capillaries. Nevertheless, problems are frequently being reported when buffers in the pH range between 4 and 7 are used. Thus the surface chemistry has been studied by X-ray photoelectron spectroscopy. Silicon-carbon bindings have been found on inner capillary surfaces for electrophoresis. This binding type is not completely removed by pre-conditioning with 1 M NaOH for 30 min. This corresponds to the result, that capillaries provide more stable migration times, especially in the pH range 4-7, when they are pre-conditioned for longer than 1 h. The origin of this Si-C bond is still not quite clear. They could be caused by graphite which is used during the fabrication of the raw cylinders prior to capillary drawing. Further investigations are intended in order to understand if there are any differences in surface carbon content from batch to batch and if this can influence experimental results in CE. A better understanding of the surface chemistry should not only improve robustness in CE, but also help to facilitate and accelerate capillary pre-conditioning and rinsing procedures to remove strongly adsorbed analytes or matrices. PMID:11100849

  3. Cell adhesion during bullet motion in capillaries.

    PubMed

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis. PMID:27261363

  4. Evaporation and instabilities of microscopic capillary bridges

    PubMed Central

    Maeda, Nobuo; Israelachvili, Jacob N.; Kohonen, Mika M.

    2003-01-01

    The formation and disappearance of liquid bridges between two surfaces can occur either through equilibrium or nonequilibrium processes. In the first instance, the bridge molecules are in thermodynamic equilibrium with the surrounding vapor medium. In the second, chemical potential gradients result in material transfer; mechanical instabilities, because of van der Waals force jumps on approach or a Rayleigh instability on rapid separation, may trigger irreversible film coalescence or bridge snapping. We have studied the growth and disappearance mechanisms of laterally microscopic liquid bridges of three hydrocarbon liquids in slit-like pores. At rapid slit-opening rates, the bridges rupture by means of a mechanical instability described by the Young–Laplace equation. Noncontinuum but apparently reversible behavior is observed when a bridge is held at nanoscopic surface separations H close to the thermodynamic equilibrium Kelvin length, 2rKcosθ, where rK is the Kelvin radius and θ is the contact angle. During the course of slow evaporation (at H > 2rKcosθ) and subsequent regrowth by capillary condensation (at H < 2rKcosθ), the refractive index of the bridge may vary continuously and reversibly between that of the bulk liquid and vapor. The evaporation process becomes irreversible only at the very final stage of evaporation, when the refractive index of the fluid attains virtually that of the vapor. Measured refractive index profiles and the time-dependence of evaporating neck diameters also seem to differ from predictions based on a continuum picture of bridge evaporation far from the critical point. We discuss these findings in terms of the probable density profiles in evolving liquid bridges. PMID:12538868

  5. L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol

    PubMed Central

    2013-01-01

    Background Given its availability and low price, glycerol derived from biodiesel industry has become an ideal feedstock for the production of fuels and chemicals. A solution to reduce the negative environmental problems and the cost of biodiesel is to use crude glycerol as carbon source for microbial growth media in order to produce valuable organic chemicals. In the present paper, crude glycerol was used as carbon substrate for production of L (+)-lactic acid using pelletized fungus R. oryzae NRRL 395 on batch fermentation. More, the experiments were conducted on media supplemented with inorganic nutrients and lucerne green juice. Results Crude and pure glycerols were first used to produce the highest biomass yield of R. oryzae NRRL 395. An enhanced lactic acid production then followed up using fed-batch fermentation with crude glycerol, inorganic nutrients and lucerne green juice. The optimal crude glycerol concentration for cultivating R. oryzae NRRL 395 was 75 g l-1, which resulted in a fungal biomass yield of 0.72 g g-1 in trial without lucerne green juice addition and 0.83 g g-1 in trial with lucerne green juice. The glycerol consumption rate was 1.04 g l-1 h-1 after 48 h in trial with crude glycerol 75 g l-1 while in trial with crude glycerol 10 g l-1 the lowest rate of 0.12 g l-1 h-1 was registered. The highest L (+)-lactic acid yield (3.72 g g-1) was obtained at the crude glycerol concentration of 75 g l-1 and LGJ 25 g l-1, and the concentration of lactic acid was approximately 48 g l-1. Conclusions This work introduced sustainable opportunities for L (+)-lactic acid production via R. oryzae NRRL 395 fermentation on biodiesel crude glycerol media. The results showed good fungal growth on crude glycerol at 75 g l-1 concentration with lucerne green juice supplementation of 25 g l-1. Lucerne green juice provided a good source of nutrients for crude glycerol fermentation, without needs for supplementation with inorganic nutrients

  6. Use of molecular dynamics to assess the biophysiological role of hydroxyl groups in glycerol dyalkyl glycerol teraethers

    NASA Astrophysics Data System (ADS)

    Huguet, Carme; Costenaro, Lionel; Fietz, Susanne; Daura, Xavier

    2015-04-01

    The cell membrane of some Archaea is constituted by lipids that span the whole membrane width and contain two alkyl chains bound by two glycerol groups (glycerol dyalkyl glycerol teraethers or GDGTs). These lipids confer stability to the membrane in mesophile to extremophile environments. Besides the more frequently studied isoprenoid archaeal lipids, both mono- and dihydroxy-GDGTs (OH-GDGT) have been recently reported to occur in marine sediments (1). OH-GDGTs contain up to two cyclopentane moieties and have been identified in both core and intact forms. In 2013, a correlation between OH-GDGTs and temperature was reported, with higher relative OH-GDGT abundances at high latitudes (2,3). The physiological function of the hydroxyl group in a GDGT is not yet known, but given the field results, it could be linked to an adaptation of the membrane to changes in temperature. For hydroxydiether lipid cores in methanogenic bacteria, it has been postulated that the hydroxyl group may alter the cell membrane properties: either extending the polar head group region or creating a hydrophilic pocket (4). It has also been suggested that the hydroxylation of the biphytany (l) moiety may result in enhanced membrane rigidity (1). To improve our understanding of the effect of the hydroxylation on physical properties of membranes, we performed molecular-dynamics simulations of GDGT membranes presenting and lacking these additional OH groups. This is an approach with a great development potential in the archaea lipid field, especially in relation to proxy validation. Our results indicate that the addition of an OH increases the membrane fluidity, thus providing an advantage in cold environments. We also observe a widening of the polar head group area, which could enhance transport. 1. Liu et al. 2012, GCA 2. Huguet et al. 2013, Org. Geochem 3. Fietz et al. 2013 4. Sprott et al. 1990. J. Biol. Chem. 265, 13735-13740.

  7. Capillary liquid chromatography using laser-based and mass spectrometric detection

    SciTech Connect

    Sepaniak, M.J.; Cook, K.D.

    1990-01-01

    The DOE-supported research performed during the past year has mainly focused on investigating and minimizing three problems that limit the practical utility of these capillary electrokinetic separation techniques in chemical analysis. (1) Analyses are hindered by poor reproducibility. This is largely a result of complicated and irreproducible capillary wall-solute interactions that often result in adsorption and mobility changes. (2) While the (micellar electrokinetic capillary chromatography) (MECC) technique permits the separations of neutral solutes, hydrophobic compounds are difficult to separate and manipulation of capacity factors (k's) is critically important. (3) The very small solute band volumes require that on-column detection be performed (usually optical detection) and this seriously limits detectability. In addition to these projects, the electrokinetic equivalent of affinity chromatography and development of remote fiber-optic sensors to measure chemical carcinogens and other compounds have been investigated. 5 refs., 2 figs.

  8. Capillary length in a fluid-fluid demixed colloid-polymer mixture.

    PubMed

    Aarts, D G A L

    2005-04-21

    We report measurements of the interfacial profile close to a vertical wall in a fluid-fluid demixed colloid-polymer mixture. The profile is measured by means of laser scanning confocal microscopy. It is accurately described by the interplay between the Laplace and hydrostatic pressure and from this description the capillary length is obtained. For different statepoints approaching the critical point the capillary length varies from 50 to 5 microm. These results are compared to theory. The mass density difference Deltarho is calculated from the bulk phase behavior, which is described within free volume theory with polymers modeled as penetrable hard spheres. The interfacial tension gamma is calculated within a squared gradient approximation. The capillary length is then given through with g equal to the Earth's acceleration. Predictions from theory are in overall qualitative agreement with experiment without the use of any adjustable parameter. PMID:16851848

  9. Evaporation on/in Capillary Structures of High Heat Flux Two-Phase Devices

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Khrustalev, Dmitry

    1996-01-01

    Two-phase devices (heat pipes, capillary pumped loops, loop heat pipes, and evaporators) have become recognized as key elements in thermal control systems of space platforms. Capillary and porous structures are necessary and widely used in these devices, especially in high heat flux and zero-g applications, to provide fluid transport and enhanced heat transfer during vaporization and condensation. However, some unexpected critical phenomena, such as dryout in long heat pipe evaporators and high thermal resistance of loop heat pipe evaporators with high heat fluxes, are possible and have been encountered in the use of two-phase devices in the low gravity environment. Therefore, a detailed fundamental investigation is proposed to better understand the fluid behavior in capillary-porous structures during vaporization at high heat fluxes. The present paper addresses some theoretical aspects of this investigation.

  10. Nucleation theory - Is replacement free energy needed?. [error analysis of capillary approximation

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.

    1982-01-01

    It has been suggested that the classical theory of nucleation of liquid from its vapor as developed by Volmer and Weber (1926) needs modification with a factor referred to as the replacement free energy and that the capillary approximation underlying the classical theory is in error. Here, the classical nucleation equation is derived from fluctuation theory, Gibb's result for the reversible work to form a critical nucleus, and the rate of collision of gas molecules with a surface. The capillary approximation is not used in the derivation. The chemical potential of small drops is then considered, and it is shown that the capillary approximation can be derived from thermodynamic equations. The results show that no corrections to Volmer's equation are needed.

  11. Preparation of Monolithic Capillary Chromatographic Columns Using Supercritical Fluid as a Porogen Solvent.

    PubMed

    Szumski, Michał; Buszewski, Bogusław

    2014-01-01

    Monolithic polymeric beds were synthesized in fused silica capillaries using either trimethylolpropane trimethacrylate (TRIM) or a mixture of butyl methacrylate (BMA) with ethylene glycol dimethacrylate (EDMA) as monomers. Carbon dioxide at temperature and pressure conditions above its critical values was used as a porogen solvent. The purpose of using the supercritical carbon dioxide was to have the possibility of changing the solvation power (and thus the porosity of the resulting monolith) of the porogen by pressure and temperature changes instead of changing the porogen composition. The experiments were performed using a special setup consisting of a stainless steel high-pressure reactor to which the fused silica capillary was connected. The synthesized monoliths underwent liquid chromatographic evaluation. The polyTRIM capillary monoliths were characterized by different permeability, which depended on the pressure of the synthesis. BMA/EDMA columns were applied for separation of alkylbenzenes and a model mixture of proteins. PMID:25089047

  12. Protease activation in glycerol-based deep eutectic solvents

    PubMed Central

    Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

    2011-01-01

    Deep eutectic solvents (DESs) consisting of mixtures of a choline salt (chloride or acetate form) and glycerol are prepared as easily accessible, biodegradable, and inexpensive alternatives to conventional aprotic cation-anion paired ionic liquids. These DES systems display excellent fluidity coupled with thermal stability to nearly 200 °C. In this work, the transesterification activities of cross-linked proteases (subtilisin and α-chymotrypsin), immobilized on chitosan, were individually examined in these novel DESs. In the 1:2 molar ratio mixture of choline chloride/glycerol containing 3% (v/v) water, cross-linked subtilisin exhibited an excellent activity (2.9 μmo l min−1 g−1) in conjunction with a selectivity of 98% in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol. These highly encouraging results advocate more extensive exploration of DESs in protease-mediated biotransformations of additional polar substrates and use of DESs in biocatalysis more generally. PMID:21909232

  13. Dynamical and orientational structural crossovers in low-temperature glycerol

    NASA Astrophysics Data System (ADS)

    Seyedi, Salman; Martin, Daniel R.; Matyushov, Dmitry V.

    2016-07-01

    Mean-square displacements of hydrogen atoms in glass-forming materials and proteins, as reported by incoherent elastic neutron scattering, show kinks in their temperature dependence. This crossover, known as the dynamical transition, connects two approximately linear regimes. It is often assigned to the dynamical freezing of subsets of molecular modes at the point of equality between their corresponding relaxation times and the instrumental observation window. The origin of the dynamical transition in glass-forming glycerol is studied here by extensive molecular dynamics simulations. We find the dynamical transition to occur for both the center-of-mass translations and the molecular rotations at the same temperature, insensitive to changes of the observation window. Both the translational and rotational dynamics of glycerol show a dynamic crossover from the structural to a secondary relaxation at the temperature of the dynamical transition. A significant and discontinuous increase in the orientational Kirkwood factor and in the dielectric constant is observed in the same range of temperatures. No indication is found of a true thermodynamic transition to an ordered low-temperature phase. We therefore suggest that all observed crossovers are dynamic in character. The increase in the dielectric constant is related to the dynamic freezing of dipolar domains on the time scale of simulations.

  14. Protease activation in glycerol-based deep eutectic solvents.

    PubMed

    Zhao, Hua; Baker, Gary A; Holmes, Shaletha

    2011-11-01

    Deep eutectic solvents (DESs) consisting of mixtures of a choline salt (chloride or acetate form) and glycerol are prepared as easily accessible, biodegradable, and inexpensive alternatives to conventional aprotic cation-anion paired ionic liquids. These DES systems display excellent fluidity coupled with thermal stability to nearly 200 °C. In this work, the transesterification activities of cross-linked proteases (subtilisin and α-chymotrypsin), immobilized on chitosan, were individually examined in these novel DESs. In the 1:2 molar ratio mixture of choline chloride/glycerol containing 3% (v/v) water, cross-linked subtilisin exhibited an excellent activity (2.9 μmo l min(-1) g(-1)) in conjunction with a selectivity of 98% in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol. These highly encouraging results advocate more extensive exploration of DESs in protease-mediated biotransformations of additional polar substrates and use of DESs in biocatalysis more generally. PMID:21909232

  15. Substrate versatility of polyhydroxyalkanoate producing glycerol grown bacterial enrichment culture.

    PubMed

    Moralejo-Gárate, Helena; Kleerebezem, Robbert; Mosquera-Corral, Anuska; Campos, José Luis; Palmeiro-Sánchez, Tania; van Loosdrecht, Mark C M

    2014-12-01

    Waste-based polyhydroxyalkanoate (PHA) production by bacterial enrichments generally follows a three step strategy in which first the wastewater is converted into a volatile fatty acid rich stream that is subsequently used as substrate in a selector and biopolymer production units. In this work, a bacterial community with high biopolymer production capacity was enriched using glycerol, a non-fermented substrate. The substrate versatility and PHA production capacity of this community was studied using glucose, lactate, acetate and xylitol as substrate. Except for xylitol, very high PHA producing capacities were obtained. The PHA accumulation was comparable or even higher than with glycerol as substrate. This is the first study that established a high PHA content (≈70 wt%) with glucose as substrate in a microbial enrichment culture. The results presented in this study support the development of replacing pure culture based PHA production by bacterial enrichment cultures. A process where mixtures of substrates can be easily handled and the acidification step can potentially be avoided is described. PMID:25213684

  16. Stability conditions and mechanism of cream soaps: role of glycerol.

    PubMed

    Sagitani, Hiromichi

    2014-01-01

    Fatty acids, fatty acid potassium soaps, glycerol and water are essential ingredients in the production of stable cream soaps. In this study, the behavior of these components in solution was investigated to elucidate the stability conditions and mechanism of cream soaps. It was determined that the cream soaps were a dispersion of 1:1 acid soap (1:1 molar ratio of potassium soap/fatty acid) crystals in the lamellar gel phase, which has confirmed from the phase behavior diagrams and small angle X-ray scattering data. Glycerol was crucial ingredient in the formation of the lamellar gel phase. The cleansing process of the cream soaps was also evaluated using the same diagrams. The structure of the continuous phase in cream soaps changed from lamellar gel to a micellar aqueous solution upon the addition of water. This structural change during the washing process is important in producing the foaming activity of acid soaps to wash away dirt or excess fats from the skin surface. PMID:24671023

  17. Crystal structure of substrate free form of glycerol dehydratase

    SciTech Connect

    Liao, Der-Ing; Dotson, Garry; Turner, Jr., Ivan; Reiss, Lisa; Emptage, Mark

    2010-03-08

    Glycerol dehydratase (GDH) and diol dehydratase (DDH) are highly homologous isofunctional enzymes that catalyze the elimination of water from glycerol and 1,2-propanediol (1,2-PD) to the corresponding aldehyde via a coenzyme B{sub 12}-dependent radical mechanism. The crystal structure of substrate free form of GDH in complex with cobalamin and K{sup +} has been determined at 2.5 {angstrom} resolution. Its overall fold and the subunit assembly closely resemble those of DDH. Comparison of this structure and the DDH structure, available only in substrate bound form, shows the expected change of the coordination of the essential K{sup +} from hexacoordinate to heptacoordinate with the displacement of a single coordinated water by the substrate diol. In addition, there appears to be an increase in the rigidity of the K{sup +} coordination (as measured by lower B values) upon the binding of the substrate. Structural analysis of the locations of conserved residues among various GDH and DDH sequences has aided in identification of residues potentially important for substrate preference or specificity of protein-protein interactions.

  18. Diphytanyl glycerol ether distributions in sediments of the Orca Basin

    SciTech Connect

    Pease, T.K.; VanVleet, E.S.; Barre, J.S. )

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 [mu]g/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in-situ production by methanogenic or extremely halophilic archaebacteria.

  19. Diphytanyl glycerol ether distributions in sediments of the Orca Basin

    NASA Astrophysics Data System (ADS)

    Pease, Tamara K.; Van Vleet, Edward S.; Barre, Jill S.

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 μg/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in situ production by methanogenic or extremely halophilic archaebacteria.

  20. Anaerobic treatment of crude glycerol from biodiesel production.

    PubMed

    Nakazawa, M M; Silva Júnior, W R S; Kato, M T; Gavazza, S; Florencio, L

    2015-01-01

    In this study, we evaluated the use of an up-flow anaerobic sludge blanket (UASB) reactor to treat crude glycerol obtained from cottonseed biodiesel production. The laboratory-scale UASB reactor (7.0 L) was operated at ambient temperature of 26.5°C with chemical oxygen demand (COD) concentrations between 0.5 and 8.0 g/L. The volatile fatty acid contents, pH, inorganic salt contents and biogas production were monitored during a 280-day experimental period. Molecular biology techniques were used to assess the microbial diversity in the bioreactor. The reactor achieved COD removal efficiencies of up to 92% except during one phase when the efficiency decreased to 81%. Biogas production remained stable throughout the experimental period, when the fraction converted to methane reached values as high as 68%. The profile of the denaturing gradient gel electrophoresis (DGGE) bands suggested slight changes in the microbial community during reactor operation. The overall results indicated that the crude glycerol from biodiesel production can serve as a suitable substrate for anaerobic degradation with a stable reactor performance and biogas production as long as the applied organic loads are up to 8.06 kg COD/m3·d. PMID:26465309

  1. Dynamical and orientational structural crossovers in low-temperature glycerol.

    PubMed

    Seyedi, Salman; Martin, Daniel R; Matyushov, Dmitry V

    2016-07-01

    Mean-square displacements of hydrogen atoms in glass-forming materials and proteins, as reported by incoherent elastic neutron scattering, show kinks in their temperature dependence. This crossover, known as the dynamical transition, connects two approximately linear regimes. It is often assigned to the dynamical freezing of subsets of molecular modes at the point of equality between their corresponding relaxation times and the instrumental observation window. The origin of the dynamical transition in glass-forming glycerol is studied here by extensive molecular dynamics simulations. We find the dynamical transition to occur for both the center-of-mass translations and the molecular rotations at the same temperature, insensitive to changes of the observation window. Both the translational and rotational dynamics of glycerol show a dynamic crossover from the structural to a secondary relaxation at the temperature of the dynamical transition. A significant and discontinuous increase in the orientational Kirkwood factor and in the dielectric constant is observed in the same range of temperatures. No indication is found of a true thermodynamic transition to an ordered low-temperature phase. We therefore suggest that all observed crossovers are dynamic in character. The increase in the dielectric constant is related to the dynamic freezing of dipolar domains on the time scale of simulations. PMID:27575188

  2. Theoretical studies on the unimolecular decomposition of propanediols and glycerol.

    PubMed

    Ye, Lili; Zhang, Feng; Zhang, Lidong; Qi, Fei

    2012-05-10

    Polyols, a typical type of alcohol containing multiple hydroxyl groups, are being regarded as a new generation of a green energy platform. In this paper, the decomposition mechanisms for three polyol molecules, i.e., 1,2-propanediol, 1,3-propanediol, and glycerol, have been investigated by quantum chemistry calculations. The potential energy surfaces of propanediols and glycerol have been built by the QCISD(T) and CBS-QB3 methods, respectively. For the three molecules studied, the H(2)O-elimination and C-C bond dissociation reactions show great importance among all of the unimolecular decomposition channels. Rate constant calculations further demonstrate that the H(2)O-elimination reactions are predominant at low temperature and pressure, whereas the direct C-C bond dissociation reactions prevail at high temperature and pressure. The temperature and pressure dependence of calculated rate constants was demonstrated by the fitted Arrhenius equations. This work aims to better understand the thermal decomposition process of polyols and provide useful thermochemical and kinetic data for kinetic modeling of polyols-derived fuel combustion. PMID:22515339

  3. Hydrogen production by sorption-enhanced steam reforming of glycerol.

    PubMed

    Dou, Binlin; Dupont, Valerie; Rickett, Gavin; Blakeman, Neil; Williams, Paul T; Chen, Haisheng; Ding, Yulong; Ghadiri, Mojtaba

    2009-07-01

    Catalytic steam reforming of glycerol for H(2) production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400-700 degrees C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in situ CO(2) removal. The product gases were measured by on-line gas analysers. The results show that H(2) productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500 degrees C. The results suggest an optimal temperature of approximately 500 degrees C for the glycerol steam reforming with in situ CO(2) removal using calcined dolomite as the sorbent, at which the CO(2) breakthrough time is longest and the H(2) purity is highest. The shrinking core model and the 1D-diffusion model describe well the CO(2) removal under the conditions of this work. PMID:19318245

  4. Diphytanyl glycerol ether distributions in sediments of the Orca Basin.

    PubMed

    Pease, T K; Van Vleet, E S; Barre, J S

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 micrograms/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in situ production by methanogenic or extremely halophilic archaebacteria. PMID:11540108

  5. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    PubMed

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-20

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χg ≤ 0.32), and/or "distorted ice" (0 < χg ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χg ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χg ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χg < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χg ≈ 0.38. Accordingly, in the range 0.32 < χg < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χg ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χg ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χg ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior of glassy binary

  6. Metabolic Engineering of a Glycerol-Oxidative Pathway in Lactobacillus panis PM1 for Utilization of Bioethanol Thin Stillage: Potential To Produce Platform Chemicals from Glycerol

    PubMed Central

    Kang, Tae Sun; Korber, Darren R.

    2014-01-01

    Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. PMID:25281374

  7. Metabolic engineering of a glycerol-oxidative pathway in Lactobacillus panis PM1 for utilization of bioethanol thin stillage: potential to produce platform chemicals from glycerol.

    PubMed

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2014-12-01

    Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. PMID:25281374

  8. The Lewis-acid-catalyzed synthesis of hyperbranched poly(glycerol-diacid)s in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first examples of monomeric glycerol-derived hyperbranched polyesters produced in a non-polar solvent system are reported here. The polymers were made by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutari...

  9. Degree of branching in hyperbranched poly(glycerol-co-diacid)s synthesized in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperbranched polymers were synthesized by using a Lewis acid (dibutyltin(IV)oxide) to catalyze the polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutaric acid (n=3) or azelaic acid (n=7) in toluene. These are the first examples of diacid-glycerol hyperbranc...

  10. Blockade of MUC1 expression by glycerol guaiacolate inhibits proliferation of human breast cancer cells.

    PubMed

    Smith, J S; Colon, J; Madero-Visbal, R; Isley, B; Konduri, S D; Baker, C H

    2010-10-01

    We sought to determine whether administration of glycerol guaiacolate at an optimal biological dose inhibits human breast cancer cell growth. Human breast cancer MCF-7 and ZR-75-1 cells were treated with glycerol guaiacolate and the therapeutic efficacy and biological activity of this drug was investigated on breast cancer cell growth. MCF-7 cells were injected into the mammary fat pad of overectamized female athymic nude mice. Ten days later, animals were treated with daily intraperitoneal injections of glycerol guaiacolate for six weeks. Tumor size and volume was monitored and immunohistochemistry analysis on MUC1, p21 and ki-67 was performed. Glycerol guaiacolate decreased breast cancer cell growth in a dose-dependent manner, decreased cell migration, and caused G1 cell cycle arrest. Our results demonstrate that glycerol guaiacolate inhibits MUC1 protein and mRNA expression levels and significantly increased p21 expression in human breast cancer cells as well as induced PARP cleavage. Similarly, glycerol guaiacolate inhibited breast tumor growth in vivo as well as enhanced p21 expression and decreased breast tumor cell proliferation (ki-67 expression). Collectively, our results demonstrate that glycerol guaiacolate decreased MUC1 expression and enhanced cell growth inhibition by inducing p21 expression in breast cancer cells. These findings suggest that glycerol guaiacolate may provide a novel and effective approach for the treatment of human breast cancer. PMID:21184665

  11. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa.

    PubMed

    Eraqi, Walaa A; Yassin, Aymen S; Ali, Amal E; Amin, Magdy A

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate. PMID:26942014

  12. Co-digestion of sewage sludge with glycerol to boost biogas production.

    PubMed

    Fountoulakis, M S; Petousi, I; Manios, T

    2010-10-01

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 degrees C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106+/-36 ml CH(4)/d before the addition of glycerol and 2353+/-94 ml CH(4)/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (mu(max)) and the saturation constant (K(S)) of glycerol were 0.149+/-0.015 h(-1) and 0.276+/-0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process. PMID:20434322

  13. Respiratory glycerol metabolism of Actinobacillus succinogenes 130Z for succinate production.

    PubMed

    Schindler, Bryan D; Joshi, Rajasi V; Vieille, Claire

    2014-09-01

    Actinobacillus succinogenes 130Z naturally produces among the highest levels of succinate from a variety of inexpensive carbon substrates. A few studies have demonstrated that A. succinogenes can anaerobically metabolize glycerol, a waste product of biodiesel manufacture and an inexpensive feedstock, to produce high yields of succinate. However, all these studies were performed in the presence of yeast extract, which largely removes the redox constraints associated with fermenting glycerol, a highly reduced molecule. We demonstrated that A. succinogenes cannot ferment glycerol in minimal medium, but that it can metabolize glycerol by aerobic or anaerobic respiration. These results were expected based on the A. succinogenes genome, which encodes respiratory enzymes, but no pathway for 1,3-propanediol production. We investigated A. succinogenes's glycerol metabolism in minimal medium in a variety of respiratory conditions by comparing growth, metabolite production, and in vitro activity of terminal oxidoreductases. Nitrate inhibited succinate production by inhibiting fumarate reductase expression. In contrast, growth in the presence of dimethylsulfoxide and in microaerobic conditions allowed high succinate yields. The highest succinate yield was 0.75 mol/mol glycerol (75 % of the maximum theoretical yield) in continuous microaerobic cultures. A. succinogenes could also grow and produce succinate on partially refined glycerols obtained directly from biodiesel manufacture. Finally, by expressing a heterologous 1,3-propanediol synthesis pathway in A. succinogenes, we provide the first proof of concept that A. succinogenes can be engineered to grow fermentatively on glycerol. PMID:25047181

  14. Production of 3-hydroxypropionic acid from glycerol by recombinant Pseudomonas denitrificans.

    PubMed

    Zhou, Shengfang; Catherine, Christy; Rathnasingh, Chelladurai; Somasundar, Ashok; Park, Sunghoon

    2013-12-01

    3-Hydroxypropionic acid (3-HP) can be produced from glycerol through two sequential enzymatic reactions that are catalyzed by a coenzyme B12 -dependent glycerol dehydratase and an NAD(P)(+) -dependent aldehyde dehydrogenase (ALDH), respectively. Pseudomonas denitrificans synthesizes coenzyme B12 under aerobic conditions, where NAD(P)(+) is regenerated efficiently. Hence, it is considered an ideal host for the production of 3-HP from glycerol under aerobic conditions. In this study, recombinant strains of P. denitrificans were developed and their potential for the production of 3-HP from glycerol was evaluated. When the enzymes, glycerol dehydratase (DhaB) and glycerol dehydratase reactivase (GdrAB), of Klebsiella pneumoniae were expressed heterologously, P. denitrificans could produce 3-HP at 37.7 mmol/L with 62% (mol/mol) yield on glycerol. Glucose was required as the carbon and energy sources for cell growth. The overexpression of heterologous ALDH was not essential; however, the titer and yield of 3-HP were improved to 54.7 mmol/L and 67% (mol/mol), respectively, when an ALDH gene (puuC) from K. pneumoniae was overexpressed. One serious drawback hindering the use of P. denitrificans as a recombinant host for 3-HP production is that it oxidizes 3-HP to malonate and utilizes 3-HP as a carbon source for growth. This is the first report on the development and use of recombinant P. denitrificans for 3-HP production from glycerol. PMID:23775313

  15. Co-digestion of sewage sludge with glycerol to boost biogas production

    SciTech Connect

    Fountoulakis, M.S.; Petousi, I.; Manios, T.

    2010-10-15

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 {sup o}C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 {+-} 36 ml CH{sub 4}/d before the addition of glycerol and 2353 {+-} 94 ml CH{sub 4}/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate ({mu}{sub max}) and the saturation constant (K{sub S}) of glycerol were 0.149 {+-} 0.015 h{sup -1} and 0.276 {+-} 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process.

  16. Synthesis of biodiesel fuel additives from glycerol using green chemistry and supercritical fluids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For every 3 moles of fatty acid esters produced, 1 mole of glycerol remains, ~11% of the biodiesel volume. One new method of glycerol use could be as a biodiesel fuel additive/extender using eco-friendly heterogeneous catalysts and supercritical fluids (SFs). SFs have advantages such as greater diff...

  17. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    EPA Science Inventory

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  18. Biodegradable Composites Based on Starch/EVOH/Glycerol Blends and Coconut Fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/Ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ...

  19. Glycerol Tri-Ester Derivatives as Diluents to Improve Low Temperature Properties of Vegetable Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are being sought. Twenty four vegetable oils were screened using glycerol tris (2-ethylhexanoate) [GTEH] as a diluent to improve the low temperature properties. Epoxidized soybean oil (E...

  20. Glycerol Tri-Ester Derivatives as Diluent to Improve Low Temperature Properties of Vegetable Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are under development. Increased utilization of glycerol would help biodiesel producers to become more competitive and viable. Lubricants based on vegetable oils generally suffer from po...

  1. Microstructure and molecular interaction in glycerol plasticized chitosan/poly(vinyl alcohol) blending films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly (vinyl alcohol) (PVA)/chitosan (CS) blended films plasticized by glycerol were investigated using mechanical testing, atomic force microscopy (AFM), differential scanning calorimetry (DSC) and FTIR spectroscopy, with primary emphasis on the effects of the glycerol content and the molecular weig...

  2. Evaluation of Glycerol from Biodiesel Production as a Feed Ingredient for Channel Catfish, Ictalurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is the main by-product of biodiesel production from vegetable oils and animal fats. It has been evaluated as an energy source for several farm animals. A study was conducted to examine the effects of various levels of glycerol in channel catfish, Ictalurus punctatus, diets. Fish with mean i...

  3. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa

    PubMed Central

    Eraqi, Walaa A.; Yassin, Aymen S.; Ali, Amal E.; Amin, Magdy A.

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate. PMID:26942014

  4. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) The additive meets the following specifications: Water insoluble combined lactic acid, 14-18 percent... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Lactylated fatty acid esters of glycerol and... CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene...

  5. REGIOSPECIFIC ANALYSIS OF DIRICINOLEOYL-ACYL-GLYCEROL IN CASTOR OIL USING ELECTROSPRAY IONIZATION-MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    HPLC fractions of castor oil were used to identify the regiospecific location of non-hydroxyl fatty acids on glycerol backbone in diricinoleoyl-acyl-glycerols using electrospray ionization MS3 of lithium adducts. The regiospecific ions in MS3 spectra were from the loss of 'a,B'-unsaturated fatty aci...

  6. A capillary holder for scanning detection of capillary isoelectric focusing with laser-induced fluorescence.

    PubMed

    Takahashi, Katsuyoshi; Maruo, Yuji; Kitamori, Takehiko; Shimura, Kiyohito

    2009-02-01

    A holder for a 12 cm long capillary was designed for scanning LIF detection of CIEF. The polyimide coat of a fused-silica capillary has been removed, and 1.5 mm diameter flanges have been attached near both ends. The holder is fixed on the stage of a fluorescence microscope via a translational stage, and a capillary guide is directly fixed on the microscope stage. The guide has a groove and a pressure plate for the capillary to slide in. The holder has two pulling plates with slits of 1 mm to accept the capillary just inside the flanges. The slits and the groove of the guide have been aligned. The motion of the translational stage brings the pulling plate into contact with the flange at the pulled side, and slides the capillary through the guide. The other end of the capillary is free and produces no strain on the capillary. When the motion of the stage is reversed, an unstrained contact is achieved at the other end. The baseline noise from scanning was only 50% larger than that without scanning. The fluorescence-signal variation during scanning was about 4% of the total signal, which was about twice that without scanning. PMID:19142915

  7. Gold nanoparticle-coated capillaries for protein and peptide analysis on open-tubular capillary electrochromatography.

    PubMed

    Hamer, Mariana; Yone, Angel; Rezzano, Irene

    2012-01-01

    We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary. PMID:22222978

  8. Glycerol Affects Root Development through Regulation of Multiple Pathways in Arabidopsis

    PubMed Central

    Hu, Jun; Zhang, Yonghong; Wang, Jinfang; Zhou, Yongming

    2014-01-01

    Glycerol metabolism has been well studied biochemically. However, the means by which glycerol functions in plant development is not well understood. This study aimed to investigate the mechanism underlying the effects of glycerol on root development in Arabidopsis thaliana. Exogenous glycerol inhibited primary root growth and altered lateral root development in wild-type plants. These phenotypes appeared concurrently with increased endogenous glycerol-3-phosphate (G3P) and H2O2 contents in seedlings, and decreased phosphate levels in roots. Upon glycerol treatment, G3P level and root development did not change in glycerol kinase mutant gli1, but G3P level increased in gpdhc1 and fad-gpdh mutants, which resulted in more severely impaired root development. Overexpression of the FAD-GPDH gene attenuated the alterations in G3P, phosphate and H2O2 levels, leading to increased tolerance to exogenous glycerol, which suggested that FAD-GPDH plays an important role in modulating this response. Free indole-3-acetic acid (IAA) content increased by 46%, and DR5pro::GUS staining increased in the stele cells of the root meristem under glycerol treatment, suggesting that glycerol likely alters normal auxin distribution. Decreases in PIN1 and PIN7 expression, β-glucuronidase (GUS) staining in plants expressing PIN7pro::GUS and green fluorescent protein (GFP) fluorescence in plants expressing PIN7pro::PIN7-GFP were observed, indicating that polar auxin transport in the root was downregulated under glycerol treatment. Analyses with auxin-related mutants showed that TIR1 and ARF7 were involved in regulating root growth under glycerol treatment. Glycerol-treated plants showed significant reductions in root meristem size and cell number as revealed by CYCB1;1pro::GUS staining. Furthermore, the expression of CDKA and CYCB1 decreased significantly in treated plants compared with control plants, implying possible alterations in cell cycle progression. Our data demonstrated that glycerol

  9. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    PubMed

    Hu, Jun; Zhang, Yonghong; Wang, Jinfang; Zhou, Yongming

    2014-01-01

    Glycerol metabolism has been well studied biochemically. However, the means by which glycerol functions in plant development is not well understood. This study aimed to investigate the mechanism underlying the effects of glycerol on root development in Arabidopsis thaliana. Exogenous glycerol inhibited primary root growth and altered lateral root development in wild-type plants. These phenotypes appeared concurrently with increased endogenous glycerol-3-phosphate (G3P) and H2O2 contents in seedlings, and decreased phosphate levels in roots. Upon glycerol treatment, G3P level and root development did not change in glycerol kinase mutant gli1, but G3P level increased in gpdhc1 and fad-gpdh mutants, which resulted in more severely impaired root development. Overexpression of the FAD-GPDH gene attenuated the alterations in G3P, phosphate and H2O2 levels, leading to increased tolerance to exogenous glycerol, which suggested that FAD-GPDH plays an important role in modulating this response. Free indole-3-acetic acid (IAA) content increased by 46%, and DR5pro::GUS staining increased in the stele cells of the root meristem under glycerol treatment, suggesting that glycerol likely alters normal auxin distribution. Decreases in PIN1 and PIN7 expression, β-glucuronidase (GUS) staining in plants expressing PIN7pro::GUS and green fluorescent protein (GFP) fluorescence in plants expressing PIN7pro::PIN7-GFP were observed, indicating that polar auxin transport in the root was downregulated under glycerol treatment. Analyses with auxin-related mutants showed that TIR1 and ARF7 were involved in regulating root growth under glycerol treatment. Glycerol-treated plants showed significant reductions in root meristem size and cell number as revealed by CYCB1;1pro::GUS staining. Furthermore, the expression of CDKA and CYCB1 decreased significantly in treated plants compared with control plants, implying possible alterations in cell cycle progression. Our data demonstrated that glycerol

  10. Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol.

    PubMed

    Wang, Zichao; Wu, Jianrong; Zhu, Li; Zhan, Xiaobei

    2016-07-01

    Many studies have focused on using crude glycerol from biodiesel to obtain valuable products, but few of these studies have focused on obtaining polysaccharides. A mutant strain of Xanthomonas campestris CCTCC M2015714 that could use glycerol to produce high-transparency and low-viscosity xanthan gum was obtained by adaptive evolution, and the yield of xanthan gum reached 11.0g/L. We found that transcriptional levels of genes related to glycerol metabolism (glpF, glpK, glpD, and fbp) in the mutant strain were all higher than those from the parent strain. Using 5g/L sucrose or glucose as starter substrate, cell growth time decreased from 36h to 24h and xanthan gum yield increased. Moreover, the mutant strain can tolerate high titer glycerol, and its activity was not affected by the impurities in crude glycerol. All these results proved that crude glycerol from biodiesel industries can be used for xanthan gum production. PMID:27030959

  11. Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa

    NASA Astrophysics Data System (ADS)

    Omuombo, C.; Huguet, A.; Olago, D.; Williamson, D.

    2013-12-01

    Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

  12. Temperature and pH controls on glycerol dibiphytanyl glycerol tetraether lipid composition in the hyperthermophilic crenarchaeon Acidilobus sulfurireducens.

    PubMed

    Boyd, Eric S; Pearson, Ann; Pi, Yundan; Li, Wen-Jun; Zhang, Yi Ge; He, Liu; Zhang, Chuanlun L; Geesey, Gill G

    2011-01-01

    Cyclization in glycerol dibiphytanyl glycerol tetraethers (GDGTs) results in internal cyclopentane moieties which are believed to confer thermal stability to crenarchaeal membranes. While the average number of rings per GDGT lipid (ring index) is positively correlated with temperature in many temperate environments, poor correlations are often observed in geothermal environments, suggesting that additional parameters may influence GDGT core lipid composition in these systems. However, the physical and chemical parameters likely to influence GDGT cyclization which are often difficult to decouple in geothermal systems, making it challenging to assess their influence on lipid composition. In the present study, the influence of temperature (range 65-81°C), pH (range 3.0-5.0), and ionic strength (range 10.1-55.7 mM) on GDGT core lipid composition was examined in the hyperthermoacidophile Acidilobus sulfurireducens, a crenarchaeon originally isolated from a geothermal spring in Yellowstone National Park, Wyoming. When cultivated under defined laboratory conditions, the composition of individual and total GDGTs varied significantly with temperature and to a lesser extent with the pH of the growth medium. Ionic strength over the range of values tested did not influence GDGT composition. The GDGT core lipid ring index was positively correlated with temperature and negatively correlated with pH, suggesting that A. sulfurireducens responds to increasing temperature and acidity by increasing the number of cyclopentyl rings in GDGT core membrane lipids. PMID:21125411

  13. Use of capillary electrophoresis and indirect detection to quantitate in-capillary enzyme-catalyzed microreactions.

    PubMed

    Zhang, Y; el-Maghrabi, M R; Gomez, F A

    2000-04-01

    The use of capillary electrophoresis and indirect detection to quantify reaction products of in-capillary enzyme-catalyzed microreactions is described. Migrating in a capillary under conditions of electrophoresis, plugs of enzyme and substrate are injected and allowed to react. Capillary electrophoresis is subsequently used to measure the extent of reaction. This technique is demonstrated using two model systems: the conversion of fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate by fructose-biphosphate aldolase (ALD, EC 4.1.2.13), and the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate by fructose-1,6-bisphospatase (FBPase, EC 3.1.3.11). These procedures expand the use of the capillary as a microreactor and offer a new approach to analyzing enzyme-mediated reactions. PMID:10892022

  14. Enzymatic production of glycerol carbonate from by-product after biodiesel manufacturing process.

    PubMed

    Jung, Hongsub; Lee, Youngrak; Kim, Daeheum; Han, Sung Ok; Kim, Seung Wook; Lee, Jinwon; Kim, Yong Hwan; Park, Chulhwan

    2012-08-10

    Glycerol carbonate is one of the higher value-added products derived from glycerol. In this study, glycerol carbonate (GC) was synthesized by transesterification of glycerol and dimethyl carbonate (DMC) using Novozym 435 (Candida antarctica Lipase B) at various conditions. For the enzymatic production of GC, the optimum conditions were the amount of enzyme (75 g/L), DMC/glycerol molar ratio (2.00), reaction temperature (60°C) and organic solvent (acetonitrile). Experimental investigation of the effect of water content revealed that the conversion of GC was maximized with no added water. The addition of surfactant such as Tween 80 increased the GC conversion, which finally reached 96.25% under the optimum condition and with surfactant addition. PMID:22759533

  15. Salty glycerol versus salty water surface organization: bromide and iodide surface propensities.

    PubMed

    Huang, Zishuai; Hua, Wei; Verreault, Dominique; Allen, Heather C

    2013-07-25

    Salty NaBr and NaI glycerol solution interfaces are examined in the OH stretching region using broadband vibrational sum frequency generation (VSFG) spectroscopy. Raman and infrared (IR) spectroscopy are used to further understand the VSFG spectroscopic signature. The VSFG spectra of salty glycerol solutions reveal that bromide and iodide anions perturb the interfacial glycerol organization in a manner similar as that found in aqueous halide salt solutions, thus confirming the presence of bromide and iodide anions at the glycerol surface. Surface tension measurements are consistent with the surface propensity suggested by the VSFG data and also show that the surface excess increases with increasing salt concentration, similar to that of water. In addition, iodide is shown to have more surface prevalence than bromide, as has also been determined from aqueous solutions. These results suggest that glycerol behaves similarly to water with respect to surface activity and solvation of halide anions at its air/liquid interface. PMID:23663033

  16. Moisturizing Effects of Diglycerol Combined with Glycerol on Human Stratum Corneum.

    PubMed

    Tomiie, Ai; Shinozaki, Masami; Yamada, Takeshi; Kuriyama, Juhei

    2016-08-01

    The water content of the stratum corneum was measured to investigate the skin-moisturizing property of diglycerol in water and in a lotion. The water content of the stratum corneum, to which the diglycerol solution was applied, was lower than that of the glycerol solution for 8 h. However, skin treated with diglycerol in combination with glycerol solution maintained a higher capacitance level compared with that of glycerol solution alone after 8 h. Moreover, the long-term moisturizing effect of the stratum corneum prominently appeared when diglycerol was formulated to the lotion containing glycerol and 1,3-butylene glycol. These studies suggest that diglycerol in combination with glycerol has a long-term moisturizing effect on human skin. PMID:27430380

  17. Dietary glycerol for quail: association between productive performance and COX III mRNA expression.

    PubMed

    Silva, S C C; Gasparino, E; Batista, E; Tanamati, F; Vesco, A P D; Lala, B; de Oliveira, D P

    2016-01-01

    This study was carry out to evaluate mRNA expression of mitochondrial cytochrome c oxidase III in the Pectoralis superficialis muscle of 28-day-old quails fed diets containing 0, 8, and 12% glycerol. Total RNA was extracted (N = 10) and cDNA was amplified using specifics primers for qRT-PCR. Feed efficiency and feed intake were evaluated. COX III mRNA expression in breast muscle was higher in the group fed with 12% glycerol (0.863 AU); no differences were observed in the expression of this gene between the muscle of animals fed diets without glycerol (0.357 AU) and 8% glycerol (0.415 AU). Quails that showed greater COX III mRNA expression also showed the lowest feed efficiency. These results show that there is a difference in COX III mRNA expression in breast muscle of 28-day-old quail fed diets different concentrations of glycerol. PMID:27323091

  18. Microbial conversion of glycerol to 1,3-propanediol and related compounds

    SciTech Connect

    Cameron, D.C.; Held, A.M.; Zhu, Mei-Ying

    1995-12-01

    Glycerol is a co-product of the conversion of vegetable oils and animal fats to soap, fatty acids, fatty acid esters and biodiesel fuel. We have investigated the use of both native and recombinant microorganisms for the conversion of glycerol to more valuable products. Fed-batch fermentations of glycerol by Klebsiella pneumoniae gave over 50 g/L of 1,3-propanediol (1,3-PD, trimethylene glycol) with high volumetric productivity. Escherichia coli containing genes for glycerol dehydratase and 1,3-PD oxidoreductase from K. pneumoniae also gave 1,3-PD from glycerol, but at a lower level than the native organism. Experiments with the recombinant E. coli have provided insights into ways to improve 1,3-PD production in both the recombinant and native organism and to modify the pathway for the production of compounds such as 3-hydroxypropionaldehyde and dihydroxyacetone.

  19. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise.

    PubMed

    van Rosendal, Simon Piet; Osborne, Mark Andrew; Fassett, Robert Gordon; Coombes, Jeff Scott

    2010-02-01

    Dehydration in athletes alters cardiovascular and thermoregulatory function and may inhibit endurance exercise capacity if fluid loss exceeds 2% of bodyweight (BW). If this level of dehydration cannot be prevented when starting from a state of euhydration, then athletes may create a state of hyperhydration by consuming extra fluid prior to exercise. From this hyperhydrated situation, individuals have a greater capacity to tolerate fluid loss before becoming dehydrated. Furthermore, excess pre-exercise fluid intake enhances thermoregulatory ability, as well as increasing plasma volume to maintain cardiac output. However, hyperhydrating before exercise is difficult, because a large fluid intake is typically accompanied by diuresis. Glycerol-containing beverages create an osmotic gradient in the circulation favouring fluid retention, thereby facilitating hyperhydration and protecting against dehydration. Many studies have shown that increases in body water by 1 L or more are achievable through glycerol hyperhydration. This article analyses the evidence for glycerol use in facilitating hyperhydration and rehydration, and provides guidelines for athletes wishing to use this compound. An analysis of the studies in this area indicates that endurance athletes intending to hyperhydrate with glycerol should ingest glycerol 1.2 g/kg BW in 26 mL/kg BW of fluid over a period of 60 minutes, 30 minutes prior to exercise. The effects of glycerol on total body water when used during rehydration are less well defined, due to the limited studies conducted. However, ingesting glycerol 0.125 g/kg BW in a volume equal to 5 mL/kg BW during exercise will delay dehydration, while adding glycerol 1.0 g/kg BW to each 1.5 L of fluid consumed following exercise will accelerate the restoration of plasma volume. Side effects from glycerol ingestion are rare, but include nausea, gastrointestinal discomfort and light-headedness. In summary, glycerol ingestion before, during or following exercise

  20. Capillary liquid chromatography using laser-based and mass spectrometric detection. [Capillary zone electrophoresis (CZE); micellar electrokinetic capillary kchromatography (MECC)

    SciTech Connect

    Sepaniak, M.J.; Cook, K.D.

    1992-01-01

    In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

  1. Simulations of Slow Capillary Discharges for BELLA

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey; Colella, Phillip; Geddes, Cameron; Esarey, Eric; Leemans, Wim; Mittelberger, Daniel; Bulanov, Stepan; Stoltz, Peter

    2010-11-01

    Capillary plasma channels are used to extend the propagation distance of relativistically intense laser pulses for laser plasma acceleration [1], and axial density modulation has been used to stabilize injection at LBNL. Channel formation is a complex process in which a gas is ionized via a slow discharge, and subsequently stabilized by a capillary wall via heat transfer. Here we describe simulations using a multi-species, 2-temperature plasma model to study the effects of electrical and thermal conduction, species diffusion, and externally-applied magnetic fields on this process for present experiments and to plan m-scale capillaries at reduced densities for the BELLA laser. These radially-symmetric simulations, performed with the 1D cylindrical code SCYLLA from LBNL, resolve the radial behavior of the plasma within the capillary but do not accurately describe dynamics near the ends of the capillary or near gas feed slots or jets. To understand these regions, we present results of simulations using the 3-dimensional hydrodynamics code HYDRA from Lawrence Livermore National Laboratory. We discuss work in progress on a multi-dimensional plasma model that leverages results from these simulations. References: [1] W. Leemans et al., Nat. Phys. 2, 696 (2006)

  2. Case report of lumbar intradural capillary hemangioma

    PubMed Central

    Unnithan, Ajaya Kumar Ayyappan; Joseph, T. P.; Gautam, Amol; Shymole, V.

    2016-01-01

    Background: Capillary hemangioma is a rare tumor in spinal intradural location. Despite the rarity, early recognition is important because of the risk of hemorrhage. This is a case report of a woman who had capillary hemangioma of cauda equina. Case Description: A 54 -year-old woman presented with a low backache, radiating to the left leg for 2 months. She had left extensor hallucis weakness, sensory impairment in left L5 dermatome, and mild tenderness in lower lumbar spine. Magnetic resonance imaging (MRI) LS spine showed L4/5 intradural tumor, completely occluding canal in myelogram, enhancing with contrast, s/o benign nerve sheath tumor. L4 laminectomy was done. Reddish tumor was seen originating from a single root. It was removed preserving the root. Postoperatively, she was relieved of symptoms. MRI showed no residue. Histopathology showed lobular proliferation of capillary-sized blood vessels and elongated spindle cells. Immunohistochemistry showed CD34 positivity in endothelial cell lining of blood vessel and smooth muscle actin positivity in blood vessel muscle cells. HPR-capillary hemangioma. Conclusion: Although rare, capillary hemangioma should be in the differential diagnosis of intradural tumors. It closely mimics nerve sheath tumor. PMID:27069745

  3. Passive Reactor Cooling Using Capillary Porous Wick

    SciTech Connect

    Miller, Christopher G.; Lin, Thomas F.

    2006-07-01

    Long-term reliability of actively pumped cooling systems is a concern in space-based nuclear reactors. Capillary-driven passive cooling systems are being considered as an alternative to gravity-driven systems. The high surface tension of liquid lithium makes it attractive as the coolant in a capillary-driven cooling system. A system has been conceived in which the fuel rod of a reactor is surrounded by a concentric wick through which liquid lithium flows to provide cooling under normal and emergency operating conditions. Unheated wicking experiments at three pressures using four layered screen mesh wicks of different porosities and three relatively high surface tension fluids have been conducted to gain insight into capillary phenomena for such a capillary cooling system. All fluids tested demonstrated wicking ability in each of the wick structures for all pressures, and wicking ability for each fluid increased with decreasing wick pore size. An externally heated wicking experiment with liquid lithium as the wicking fluid was also conducted. In addition to wicking experiments, a heater rod is under development to simulate the fuel rod of a space based nuclear reactor by providing a heat flux of up to 110 kW/m{sup 2}. Testing of this heater rod has shown its ability to undergo repeated cycling from below 533 K to over 1255 K without failure. This heater rod will be integrated into lithium wicking experiments to provide more realistic simulation of the proposed capillary-driven space nuclear reactor cooling system. (authors)

  4. Synthetic Capillaries to Control Microscopic Blood Flow

    PubMed Central

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  5. Capillary effects on floating cylindrical particles

    NASA Astrophysics Data System (ADS)

    Dixit, Harish N.; Homsy, G. M.

    2012-12-01

    In this study, we develop a systematic perturbation procedure in the small parameter, B1/2, where B is the Bond number, to study capillary effects on small cylindrical particles at interfaces. Such a framework allows us to address many problems involving particles on flat and curved interfaces. In particular, we address four specific problems: (i) capillary attraction between cylinders on flat interface, in which we recover the classical approximate result of Nicolson ["The interaction between floating particles," Proc. Cambridge Philos. Soc. 45, 288-295 (1949), 10.1017/S0305004100024841], thus putting it on a rational basis; (ii) capillary attraction and aggregation for an infinite array of cylinders arranged on a periodic lattice, where we show that the resulting Gibbs elasticity obtained for an array can be significantly larger than the two cylinder case; (iii) capillary force on a cylinder floating on an arbitrary curved interface, where we show that in the absence of gravity, the cylinder experiences a lateral force which is proportional to the gradient of curvature; and (iv) capillary attraction between two cylinders floating on an arbitrary curved interface. The present perturbation procedure does not require any restrictions on the nature of curvature of the background interface and can be extended to other geometries.

  6. EUV radiation from nitrogen capillary discharge

    NASA Astrophysics Data System (ADS)

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav

    2014-08-01

    In the last decade EUV sources attract interest from researchers over the world. One of the main motivations is EUV lithography, which could lead to further miniaturization in electronics. Nitrogen recombination laser at wavelength of 13.4 nm based on capillary discharge Z-pinch configuration could be used in experiments with testing of resolution of photoresist for EUV lithography (close to wavelength of 13.5 nm Si/Mo multilayer mirrors have a high reflectivity at normal incidence angles). In this work, pinching of nitrogen-filled capillary discharge is studied for the development of EUV laser, which is based on recombination pumping scheme. The goal of this study is achieving the required plasma conditions using a capillary discharge Z-pinch apparatus. In experiments with nitrogen, the capillary length was shortened from 232 mm to 90 mm and current quarter-period was changed from 60 ns to 50 ns in contrast with early experiments with Ne-like argon laser. EUV radiation from capillary discharge was registered by X-ray vacuum diode for different pressure, amplitude and duration of pre-pulse and charging voltage of the Marx generator.

  7. Synthetic Capillaries to Control Microscopic Blood Flow

    NASA Astrophysics Data System (ADS)

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-02-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function.

  8. Synthetic Capillaries to Control Microscopic Blood Flow.

    PubMed

    Sarveswaran, K; Kurz, V; Dong, Z; Tanaka, T; Penny, S; Timp, G

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using "live cell lithography"(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision-no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100-1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  9. Capillary xray compressor: principle versus practice

    NASA Astrophysics Data System (ADS)

    Brewe, Dale L.; Heald, Steve M.; Barg, Bill; Brown, Frederick C.; Kim, Kyungha H.; Stern, Edward A.

    1995-09-01

    Guiding x rays down the inside of tapered capillaries is a means to increase the flux density of x rays from synchrotron light sources without some of the disadvantages inherent in other techniques. We have demonstrated that a process based on techniques for fabrication of glass fibers may be used to produce tapered capillaries with inlet diameters on the order of 150 micrometers or more, and outlets on the order of 1 micrometer or less. We present a description of the capillary fabrication and results of tests of the performance of several capillaries, along with a comparison with calculations of performance. We also summarize refinements to the fabrication process that will provide additional improvements. The transmission of x rays from linear capillaries with inlet diameters of approximately 150 micrometers and outlet diameters of 1.3 - 1.4 micrometer is on the order of 2%, with corresponding intensity gains of up to 274. Initial results indicate that the capability exists for producing convex profiles necessary for optimal transmission. Calculated and measured transmission efficiencies are in fairly good agreement, leading to the expectation that efficiencies predicted by calculations to be attainable from optimal profiles are a realistic goal, given the ability to manufacture these profiles.

  10. Anaerobic granular sludge as a biocatalyst for 1,3-propanediol production from glycerol in continuous bioreactors.

    PubMed

    Gallardo, R; Faria, C; Rodrigues, L R; Pereira, M A; Alves, M M

    2014-03-01

    1,3-Propanediol (1,3-PDO) was produced from glycerol in three parallel Expanded Granular Sludge Blanket (EGSB) reactors inoculated with granular sludge (control reactor-R1), heat-treated granular sludge (R2) and disrupted granular sludge (R3) at hydraulic retention times (HRT) between 3 and 24h. Maximum 1,3-PDO yield (0.52molmol(-1)) and productivity (57gL(-1)d(-1)) were achieved in R1 at HRTs of 12 and 3h, respectively. DGGE profiling of PCR-amplified 16S rRNA gene fragments showed that variations in the HRT had a critical impact in the dominant community of microorganisms. However, no appreciable differences in the bacterial population were observed between R2 and R3 at low HRTs. Production of H2 was observed at the beginning of the operation, but no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors and represents a novel strategy to valorise glycerol generated in the biodiesel industry. PMID:24413479

  11. Glycerol Ester Hydrolase Activity of Lactic Acid Bacteria

    PubMed Central

    Oterholm, Anders; Ordal, Z. John; Witter, Lloyd D.

    1968-01-01

    Seventeen strains of lactic acid bacteria were assayed for their glycerol ester hydrolase activity by using an improved agar-well technique, and eight strains by determining the activity in cell-free extracts using a pH-stat procedure. All cultures tested showed activity and hydrolyzed tributyrin more actively than they did tricaproin. The cell extract studies demonstrated that the cells contained intracellular esterases and lipases. The culture supernatant fluid was without activity. The lipase and the esterase differed in their relative activity to each other in the different extracts and in the ease by which they could be freed from the cellular debris. It is suggested that the lipase of these organisms is an endoenzyme and the esterase an ectoenzyme. PMID:5649866

  12. Facile preparation of SiO2/TiO2 composite monolithic capillary column and its application in enrichment of phosphopeptides.

    PubMed

    Wang, Shao-Ting; Wang, Meng-Ya; Su, Xin; Yuan, Bi-Feng; Feng, Yu-Qi

    2012-09-18

    A novel SiO(2)/TiO(2) composite monolithic capillary column was prepared by sol-gel technology and successfully applied to enrich phosphopeptides as a metal oxide affinity chromatography (MOAC) material. For the monolith preparation, tetramethoxysilane (TMOS) and tetrabutoxytitanium (TBOT) were used as silica and titania source, respectively, and glycerol was introduced to attenuate the activity of titanium precursor, which provided a mild synthetic condition. The prepared monolith was characterized by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results revealed an approximate 1/2 molar ratio of titanium to silica as well as an atom-scale homogeneity in the framework. The scanning electron microscopy (SEM) results demonstrated an excellent anchorage between the column and the inner capillary wall, and nitrogen adsorption-desorption experiments showed a bimodal porosity with a narrow mesopore distribution around 3.6 nm. The prepared monolith was then applied for selective enrichment of phosphopeptides from the digestion mixture of phosphoproteins and bovine serum albumin (BSA) as well as human blood serum, nonfat milk, and egg white using an in-tube solid phase microextraction (SPME) system. Our results showed that SiO(2)/TiO(2) composite monolithic capillary column could efficiently enrich the phosphopeptides from complex matrixes. To the best of our knowledge, this is the first attempt for preparing the silica-metal composite monolithic capillary column, which offers the promising application of the monolith on phosphoproteomics study. PMID:22900475

  13. Oxygen Transfer in a Fluctuating Capillary Fringe: Impact of Porous Medium Heterogeneity

    NASA Astrophysics Data System (ADS)

    Haberer, C.; Rolle, M.; Cirpka, O. A.; Grathwohl, P.

    2013-12-01

    barrier effect, and air entrapment. Our results were additionally influenced by the formation of an air passage between the unsaturated zone and the coarse lens, leading to direct supply of oxygen from the atmosphere. The overall enhancement of oxygen transfer across the capillary fringe was up to seven times higher compared to what was observed in a similar experiment performed in a homogeneous porous medium. We conclude that understanding the interaction of porous medium heterogeneity, transient flow dynamics, and mass transfer processes is critical to improve our capability to quantitatively describe the exchange of volatile compounds across the capillary fringe.

  14. Capillary self-assembly of floating bodies

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan; Thompson, Paul; Bush, John

    2007-11-01

    We study the self-assembly of bodies supported on the water surface by surface tension. Attractive and repulsive capillary forces exist between menisci of, respectively, the same and opposite signs. In nature, floating objects (e.g. mosquito larvae) thus interact through capillary forces to form coherent packings on the water surface. We here present the results of an experimental investigation of such capillary pattern formation. Thin elliptical metal sheets were designed to have variable shape, flexibility and mass distribution. On the water surface, mono-, bi-, or tri-polar menisci could thus be achieved. The influence of the form of the menisci on the packings arising from the interaction of multiple floaters is explored. Biological applications are discussed.

  15. Deformation of vesicles flowing through capillaries

    NASA Astrophysics Data System (ADS)

    Vitkova, V.; Mader, M.; Podgorski, T.

    2004-11-01

    The flow of giant lipid vesicles through cylindrical capillaries is experimentally investigated. Vesicles are deflated with reduced volumes between 0.8 and 1, corresponding to prolate spheroidal equilibrium shapes. Both interior and exterior fluids are sugar solutions with viscosities close to 10-3 Pa s. Vesicles are aspirated into a capillary tube with a diameter close to the vesicle size and a constant flow rate is imposed. Significant deformation of the membrane occurs and increases when the velocity, confinement or deflation of the vesicle are increased. The mobility of vesicles, defined as the ratio of their velocity to the average velocity of the fluid is a decreasing function of confinement. Our experimental system provides a controllable and flexible tool to investigate deformability effects responsible for crucial aspects of blood rheology in capillaries.

  16. Prediction of tilted capillary barrier performance

    SciTech Connect

    Webb, S.W.; McCord, J.T.; Dwyer, S.F.

    1997-04-01

    Capillary barriers, consisting of tilted fine-over-coarse layers under unsaturated conditions, have been suggested as landfill covers to divert water infiltration away from sensitive underground regions, especially for arid and semi-arid regions. The Hydrological Evaluation of Landfill Performance (HELP) computer code is an evaluation tool for landfill covers used by designers and regulators. HELP is a quasi-two-dimensional model that predicts moisture movement into and through the underground soil and waste layers. Processes modeled within HELP include precipitation, runoff, evapotranspiration, unsaturated vertical drainage, saturated lateral drainage, and leakage through liners. Unfortunately, multidimensional unsaturated flow phenomena that are necessary for evaluating tilted capillary barriers are not included in HELP. Differences between the predictions of the HELP and those from a multidimensional unsaturated flow code are presented to assess the two different approaches. Comparisons are presented for the landfill covers including capillary barrier configurations at the Alternative Landfill Cover Demonstration (ALCD) being conducted at Sandia.

  17. 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.

  18. Directional transport of impinging capillary jet on wettability engineered surfaces

    NASA Astrophysics Data System (ADS)

    Ghosh, Aritra; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Impingement of capillary jet on a surface is important for applications like heat transfer, or for liquid manipulation in bio-microfluidic devices. Using wettability engineered surfaces, we demonstrate pump-less and directional transport of capillary jet on a flat surface. Spatial contrast of surface energy and a wedge-shape geometry of the wettability confined track on the substrate facilitate formation of instantaneous spherical bulges upon jet impingement; these bulges are further transported along the superhydrophilic tracks due to Laplace pressure gradient. Critical condition warranted for formation of liquid bulge along the varying width of the superhydrophilic track is calculated analytically and verified experimentally. The work throws light on novel fluid phenomena of unidirectional jet impingement on wettability confined surfaces and provides a platform for innovative liquid manipulation technique for further application. By varying the geometry and wettability contrast on the surface, one can achieve volume flow rates of ~ O(100 μL/sec) and directionally guided transport of the jet liquid, pumplessly at speeds of ~ O(10cm/sec).

  19. Axisymmetric Boundary Element Method for vesicles in a capillary

    NASA Astrophysics Data System (ADS)

    Trozzo, R.; Boedec, G.; Leonetti, M.; Jaeger, M.

    2015-05-01

    The problem of a vesicle transported by a fluid flow can present a large range of length scales. One example is the case of a vesicle producing a tether, and eventually pearls, in an elongational flow. Another case occurs when a lubrication film is formed, such as during the short range interaction between two vesicles. Such problems are still challenging for 3D simulations. On the other hand, a good understanding could be obtained by first considering the axisymmetric regime when such a regime exists. An axisymmetric model could then be used, without the criticisms that can be made of a 2D approach. We propose such a model, primarily interested in flows through narrow cylindrical capillaries. Two options are compared, with and without explicit representation of the capillary boundaries by a mesh. The numerical effort is characterized as a function of the vesicle's initial shape, the flow magnitude and the confinement. The model is able to treat typical configurations of red blood cells flowing through very narrow pores with extremely thin lubrication films.

  20. High-current carbon-epoxy capillary cathode

    NASA Astrophysics Data System (ADS)

    Gleizer, J. Z.; Queller, T.; Bliokh, Yu.; Yatom, S.; Vekselman, V.; Krasik, Ya. E.; Bernshtam, V.

    2012-07-01

    The results of experiments on the reproducible generation of an electron beam having a high current density of up to 300 A/cm2 and a satisfactorily uniform cross-sectional distribution of current density in a ˜200 kV, ˜450 ns vacuum diode with a carbon-epoxy capillary cathode are presented. It was found that the source of the electrons is the plasma formed as a result of flashover inside the capillaries. It is shown that the plasma formation occurs at an electric field ≤15 kV/cm and that the cathode sustains thousands of pulses without degradation in its emission properties. Time- and space-resolved visible light observation and spectroscopy analyses were used to determine the cathode plasma's density, temperature, and expansion velocity. It was found that the density of the cathode plasma decreases rapidly in relation to the distance from the cathode. In addition, it was found that the main reason for the short-circuiting of the accelerating gap is the formation and expansion of the anode plasma. Finally, it was shown that when an external guiding magnetic field is present, the injection of the electron beam into the drift space with a current amplitude exceeding its critical value changes the radial distribution of the current density of the electron beam because the inner electrons are reflected from the virtual cathode.

  1. Mach-like capillary-gravity wakes.

    PubMed

    Moisy, Frédéric; Rabaud, Marc

    2014-08-01

    We determine experimentally the angle α of maximum wave amplitude in the far-field wake behind a vertical surface-piercing cylinder translated at constant velocity U for Bond numbers Bo(D)=D/λ(c) ranging between 0.1 and 4.2, where D is the cylinder diameter and λ(c) the capillary length. In all cases the wake angle is found to follow a Mach-like law at large velocity, α∼U(-1), but with different prefactors depending on the value of Bo(D). For small Bo(D) (large capillary effects), the wake angle approximately follows the law α≃c(g,min)/U, where c(g,min) is the minimum group velocity of capillary-gravity waves. For larger Bo(D) (weak capillary effects), we recover a law α∼√[gD]/U similar to that found for ship wakes at large velocity [Rabaud and Moisy, Phys. Rev. Lett. 110, 214503 (2013)]. Using the general property of dispersive waves that the characteristic wavelength of the wave packet emitted by a disturbance is of order of the disturbance size, we propose a simple model that describes the transition between these two Mach-like regimes as the Bond number is varied. We show that the new capillary law α≃c(g,min)/U originates from the presence of a capillary cusp angle (distinct from the usual gravity cusp angle), along which the energy radiated by the disturbance accumulates for Bond numbers of order of unity. This model, complemented by numerical simulations of the surface elevation induced by a moving Gaussian pressure disturbance, is in qualitative agreement with experimental measurements. PMID:25215822

  2. Dynamics of low capillary number interfaces moving through sharp features

    NASA Astrophysics Data System (ADS)

    Reddy, Shravanthi; Schunk, P. Randall; Bonnecaze, Roger T.

    2005-12-01

    The success of any nanoimprint process depends upon its ability to exactly reproduce the template pattern. Thus, complete filling of recessed features in the template is an important issue that is controlled by the dynamics of the flow through these sharp structures. At these small scales, capillary forces are large and must be included in the fluid flow model. The mechanism of interface advancement at low capillary number through sharp rectangular features is useful for understanding how and why features fill or trap air. In this study we present a two-dimensional simulation of this feature filling to capture the details of the process, including the viscous and capillary effects. Fluid is injected into the channel between the template and substrate, where the fluid-air interface soon encounters a rectangular feature with some height greater than the channel gap. As the fluid advances through the channel, the shape of the interface is a circular arc due to the strong capillary forces. The interface maintains this circular arc as it negotiates the first sharp corner of the feature; the upper contact line effectively pins to the initial corner of the feature as it moves around this corner, during which time the lower contact line continues to advance forward along the substrate surface, causing the interface to stretch. For sufficiently wide or shallow features, once the upper contact line has negotiated the first corner and has moved vertically up the inner wall of the feature, it must move through the top corner of the feature. At this point the interface undergoes a rapid reconfiguration from a high surface area circular arc to a lower surface area circular arc inside the feature. Alternatively, for narrow or high features, the stretched interface can catch on the far, final corner of the feature, trapping air inside the feature and preventing filling. The conditions for filling are studied parametrically for a variety of wetting contact angles and feature

  3. Control of electroosmosis in coated quartz capillaries

    NASA Technical Reports Server (NTRS)

    Herren, Blair J.; Van Alstine, James; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1987-01-01

    The effectiveness of various coatings for controlling the electroosmotic fluid flow that hinders electrophoretic processes is studied using analytical particle microelectrophoresis. The mobilities of 2-micron diameter glass and polystyrene latex spheres (exhibiting both negative and zero effective surface charge) were measured in 2-mm diameter quartz capillaries filled with NaCl solutions within the 3.5-7.8 pH range. It is found that capillary inner surface coatings using 5000 molecular weight (or higher) poly(ethylene glycol): significantly reduced electroosmosis within the selected pH range, were stable for long time periods, and appeared to be more effective than dextran, methylcellulose, or silane coatings.

  4. A lymph nodal capillary-cavernous hemangioma.

    PubMed

    Dellachà, A; Fulcheri, E; Campisi, C

    1999-09-01

    A capillary-cavernous hemangioma in an obturator lymph node was found incidentally in a 64 year-old woman who had undergone unilateral salpingo-oophorectomy and lymphadenectomy for an ovarian neoplasm. Vascular tumors of lymph nodes are briefly reviewed including eight previously described nodal capillary-cavernous hemangiomas. The association with other splanchnic hemangiomas is pointed out and the likelihood that the lesion is a hamartoma rather than a true neoplasm is addressed. Despite its rarity, this entity needs to be recognized by lymphologists who image lymph nodes by lymphangiography as well as by lymph nodal pathologists. PMID:10494525

  5. Use of Plastic Capillaries for Macromolecular Crystallization

    NASA Technical Reports Server (NTRS)

    Potter, Rachel R.; Hong, Young-Soo; Ciszak, Ewa M.

    2003-01-01

    Methods of crystallization of biomolecules in plastic capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods used batch, free-interface liquid- liquid diffusion alone, or a combination with vapor diffusion. Results demonstrated growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as protein studied in our laboratory such dihydrolipoamide dehydrogenase. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until the desired time of activation of crystallization experiments.

  6. Capillary origami and superhydrophobic membrane surfaces

    NASA Astrophysics Data System (ADS)

    Geraldi, N. R.; Ouali, F. F.; Morris, R. H.; McHale, G.; Newton, M. I.

    2013-05-01

    Capillary origami uses surface tension to fold and shape solid films and membranes into three-dimensional structures. It uses the fact that solid surfaces, no matter how hydrophobic, will tend to adhere to and wrap around the surface of a liquid. In this work, we report that a superhydrophobic coating can be created, which can completely suppress wrapping as a contacting water droplet evaporates. We also show that using a wetting azeotropic solution of allyl alcohol, which penetrates the surface features, can enhance liquid adhesion and create more powerful Capillary Origami. These findings create the possibility of selectively shaping membrane substrates.

  7. Laser absorption waves in metallic capillaries

    NASA Astrophysics Data System (ADS)

    Anisimov, V. N.; Arutiunian, R. V.; Bol'Shov, L. A.; Kanevskii, M. F.; Kondrashov, V. V.

    1987-07-01

    The propagation of laser absorption waves in metallic capillaries was studied experimentally and numerically during pulsed exposure to CO2 laser radiation. The dependence of the plasma front propagation rate on the initial air pressure in the capillary is determined. In a broad range of parameters, the formation time of the optically opaque plasma layer is governed by the total laser pulse energy from the beginning of the exposure to the instant screening appears, and is weakly dependent on the pulse shape and gas pressure.

  8. Analysis of Stevia glycosides by capillary electrophoresis.

    PubMed

    Mauri, P; Catalano, G; Gardana, C; Pietta, P

    1996-02-01

    The determination of diterpene glycosides from Stevia rebaudiana leaves using capillary electrophoresis is described. Analyses were performed on fused silica capillaries with 20 mM sodium tetraborate buffer, pH 8.3, and 30 mM sodium dodecyl sulfate. The effect of the organic solvent injected with the sample solution on the electrophoretic solution has been confirmed, and an absolute amount of 1.6 nL per injected sample was optimal. Rebaudioside A and steviolbioside were isolated by semipreparative high performance liquid chromatography (HPLC), and their structure was assessed by mass spectrometry. PMID:8900944

  9. Effect of glycerol on ischemic cerebral edema assessed by magnetic resonance imaging.

    PubMed

    Sakamaki, Masanori; Igarashi, Hironaka; Nishiyama, Yutaka; Hagiwara, Hiroshi; Ando, Jun; Chishiki, Tetsurou; Curran, Brian C; Katayama, Yasuo

    2003-05-15

    The aim of this study is to assess the anticerebral edema effect of glycerol on a large cerebral infarction with magnetic resonance imaging (MRI). Glycerol, which is widely used as an osmotic agent against cerebral edema, could exacerbate brain tissue shift, since it has been suggested that glycerol might shrink a noninfarcted hemisphere and worsen the mass effect after a large hemispheric cerebral infarction. To investigate these issues, changes in a large hemispheric infarction with cerebral edema were studied using MRI before and after glycerol administration. Infarct volumes, normal brain tissue volumes and lateral ventricle volumes, in addition to signal intensities of T(2)-weighted images, were measured in six patients before and after administration of 300 ml of glycerol. Ventricle volumes were significantly increased (p=0.0015) and the T(2) signal intensity of the post-treatment ischemic region decreased after glycerol administration. In contrast, no significant differences in either cerebral volume or T(2) signal intensity were seen in the noninfarcted hemisphere before and after administration. Our data suggest that glycerol does not exacerbate the mass effect on a large hemispheric infarction. PMID:12686405

  10. Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

    PubMed Central

    ATHURUPANA, Rukmali; TAKAHASHI, Daisen; IOKI, Sumire; FUNAHASHI, Hiroaki

    2015-01-01

    Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa. PMID:25754239

  11. Metabolic effects of glycerol supplementation and aerobic physical training on Wistar rats.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Gomes, Núbia Ferreira; Alvarenga, Renata Ribeiro; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Pereira, Luciano José

    2014-09-01

    We evaluated the effects of oral glycerol supplementation on trained rats fed a normal diet. Wistar rats were distributed among 6 groups in a completely randomized 2 × 3 factorial design. The animals were subjected to 6 weeks of aerobic training. In the last 4 weeks, the animals' diet was supplemented with saline, glucose, or glycerol. Data were subjected to one-way analysis of variance (ANOVA) followed by a Student-Newmann-Keuls test, with values for P < 0.05 considered statistically significant. The change in body mass was lower in the trained groups, and their food and water consumption were higher. Glycerol supplementation resulted in an increase in the levels of triacylglycerol (TAG) and total cholesterol, as well as in the area and diameter of adipocytes. When associated with training, these parameters were similar to those of other trained groups. Levels of low-density lipoprotein + very-low-density lipoprotein cholesterol decreased in the trained animals that received glycerol compared with the non-trained ones. Glycerol consumption caused a reduction in food intake and increased the villous:crypt (V:C) ratio. No changes in glycemia, high density lipoproteins, or density of adipocytes were observed. Supplementation with glycerol together with aerobic physical training promoted beneficial metabolic effects. However, in non-trained rats glycerol increased the diameter and area of adipocytes, as well as the levels of TAG and total cholesterol. PMID:25105723

  12. Fermentation of glycerol into ethanol in a microbial electrolysis cell driven by a customized consortium.

    PubMed

    Speers, Allison M; Young, Jenna M; Reguera, Gemma

    2014-06-01

    The in situ generation of ethanol from glycerol-containing wastewater shows promise to improve the economics of the biodiesel industry. Consequently, we developed a microbial electrolysis cell (MEC) driven by the synergistic metabolisms of the exoelectrogen Geobacter sulfurreducens and the bacterium Clostridium cellobioparum, which fermented glycerol into ethanol in high yields (90%) and produced fermentative byproducts that served as electron donors for G. sulfurreducens. Syntrophic cooperation stimulated glycerol consumption, ethanol production, and the conversion of fermentation byproducts into cathodic H2 in the MEC. The platform was further improved by adaptively evolving glycerol-tolerant strains with robust growth at glycerol loadings typical of biodiesel wastewater and by increasing the buffering capacity of the anode medium. This resulted in additional increases in glycerol consumption (up to 50 g/L) and ethanol production (up to 10 g/L) at rates that greatly exceeded the capacity of the anode biofilms to concomitantly remove the fermentation byproducts. As a result, 1,3-propanediol was generated as a metabolic sink for electrons not converted into electricity syntrophically. The results highlight the potential of consortia to process glycerol in MECs and provide insights into genetic engineering and system design approaches that can be implemented to further improve MEC performance to satisfy industrial needs. PMID:24802954

  13. Hydrogenolysis of Glycerol to 1,2-Propanediol Over Clay Based Catalysts.

    PubMed

    Lee, Sang-Yong; Jung, Jae-Sun; Yang, Eun-Hyeok; Lee, Kwan-Young; Moon, Dong Ju

    2015-11-01

    1,2-propanediol (1,2-PDO) is one of the promising product among the valuable products derived from glycerol and it can be obtained by the catalytic hydrogenolysis of glycerol. Copper-supported clay-based catalysts were prepared with different pore sizes using various ratios of kaolin, Mg, and Al by coprecipitation and applied in the selective hydrogenolysis of glycerol to 1,2-PDO. In recent research, variations of pore volume and pore size could affect the diffusion of reagents within the catalyst due to the collision between reagents or pore wall and reagents. It changes selectivities of each product in hydrogenolysis of glycerol reaction. The physico-chemical properties of the catalysts were analyzed by XRD, N2 physisorption, TPR, CO2-TPD, SEM, and a mercury porosimeter. The Cu/TALCITE 4 catalyst showed 98% 1,2-PDO selectivity with 65% glycerol conversion under the optimized condition of 190 degrees C, 25 bar, and 20 wt% glycerol aqueous solution. It was found that the basic strength and meso-macro pore structure of the catalysts play an important role in glycerol conversion and 1,2-PDO selectivity. PMID:26726594

  14. Meta-analysis: Effects of glycerol administration on plasma volume, haemoglobin, and haematocrit.

    PubMed

    Koehler, Karsten; Thevis, Mario; Schaenzer, Wilhelm

    2013-01-01

    The use of glycerol in combination with excess fluid can be used to increase total body water. Because glycerol hyperhydration may also be misused to mask the effects of blood doping on doping-relevant parameters, namely haemoglobin and haematocrit, glycerol has been prohibited by the World Anti-Doping Agency since 2010. In order to test this rationale, the purpose of this meta-analysis was to quantify the effects of glycerol hyperhydration on plasma volume, haemoglobin, and haematocrit in comparison to administration of fluid only. Following a literature search, a total of seven studies was included and meta-analyses were performed separately for the effects on plasma volume (5 studies, total n = 54) and on haemoglobin (6 studies, n = 52) and haematocrit (6 studies, n = 52). The meta-analysis revealed that the increase in plasma volume was 3.3% larger (95%-CI: 1.1-5.5%) after glycerol administration when compared to fluid only. Reductions in haemoglobin were 0.2 g/dl (95%-CI: -0.3, 0.0) larger and there was no difference in the changes in haematocrit between glycerol and fluid administration (95%-CI: -0.7-0.8%). In comparison with other plasma-volume expanding agents, glycerol hyperhydration has a very limited potential in increasing plasma volume and altering doping-relevant blood parameters. PMID:24353192

  15. Physiologic Mechanisms Involved in Accumulation of 3-Hydroxypropionaldehyde during Fermentation of Glycerol by Enterobacter agglomerans

    PubMed Central

    Barbirato, F.; Soucaille, P.; Bories, A.

    1996-01-01

    When grown in 700 mM glycerol within the pH range 6.0 to 7.5, anaerobic pH-regulated cultures of Enterobacter agglomerans exhibited an extracellular accumulation of 3-hydroxypropionaldehyde (3-HPA). This phenomenon, which causes fermentation cessation, occurred earlier when pH was low. In contrast, substrate consumption was complete at pH 8. Levels of glycerol-catabolizing enzymes, i.e., glycerol dehydrogenase and dihydroxyacetone kinase for the oxidative route and glycerol dehydratase and 1,3-propanediol dehydrogenase for the reductive route, as well as the nucleotide pools were determined periodically in the pH 7- and pH 8-regulated cultures. A NAD/NADH ratio of 1.7 was correlated with the beginning of the production of the inhibitory metabolite. Further accumulation was dependent on the ratio of glycerol dehydratase activity to 1,3-propanediol dehydrogenase activity. For a ratio higher than 1, 3-HPA was produced until fermentation ceased, which occurred for the pH 7-regulated culture. At pH 8, a value below 1 was noticed and 3-HPA accumulation was transient, while the NAD/NADH ratio decreased. The low rate of glycerol dissimilation following the appearance of 3-HPA in the culture medium was attributed to the strong inhibitory effect exerted by 3-HPA on glycerol dehydrogenase activity. PMID:16535461

  16. Earlobe arterialized capillary blood gas analysis in the intensive care unit: a pilot study

    PubMed Central

    2014-01-01

    Background Earlobe arterialized capillary blood gas analysis can be used to estimate arterial gas content and may be suitable for diagnosis and management of critically ill patients. However, its utility and applicability in the ICU setting remains unexplored. Methods A prospective observational validation study was designed to evaluate this technique in a cohort of mechanically ventilated adult critically ill patients admitted to a polyvalent ICU. Precision and agreement between capillary gas measures and arterial references was examined. Acute Respiratory Distress Syndrome (ARDS) diagnosis capabilities with the proposed technique were also evaluated. Finally, factors associated with sampling failure were explored. Results Fifty-five patients were included into this study. Precision of capillary samples was high (Coefficient of Variation PO2 = 9.8%, PCO2 = 7.7%, pH = 0.3%). PO2 measures showed insufficient agreement levels (Concordance Correlation Coefficient = 0.45; bias = 12 mmHg; percentage of error = 19.3%), whereas better agreement was observed for PCO2 and pH (Concordance Correlation Coefficient = 0.94 and 0.93 respectively; depreciable bias; percentage of error 11.4% and 0.5% respectively). The sensitivity and specificity for diagnosing ARDS were 100% and 92.3% using capillary gasometric measures. Sampling was unsuccessful in 43.6% of cases due to insufficient blood flow. Age > 65 years was independently associated with failure (odds ratio = 1.6), however hemodynamic failure and norepinephrine treatment were also influencing factors. Conclusions Earlobe capillary blood gas analysis is precise and can be useful for detecting extreme gasometrical values. Diagnosis of ARDS can be done accurately using capillary measurements. Although this technique may be insufficient for precise management of patients in the ICU, it has the potential for important benefits in the acute phase of various critical conditions and in other

  17. Influence of water availability in the distributions of branched glycerol dialkyl glycerol tetraether in soils of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Menges, J.; Huguet, C.; Alcañiz, J. M.; Fietz, S.; Sachse, D.; Rosell-Melé, A.

    2014-05-01

    The combined application of the MBT (degree of methylation) and CBT (degree of cyclization) indices, based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils, has been proposed as a paleoproxy to estimate mean annual temperature (MAT). CBT quantifies the degree of cyclization of brGDGTs and relates to soil pH. MBT and the simplified version MBT' quantify the degree of methylation of brGDGTs and relate to MAT and soil pH. However, other factors such as soil water availability have also been suggested to influence MBT' and possibly restrict the combined application of the MBT' and CBT indices as a paleotemperature proxy. To assess the effect of hydrological conditions on MBT' and CBT, a set of 23 Iberian Peninsula soil samples, covering a MAT range from 10 to 18 °C and a mean annual precipitation (MAP) range of 405 mm to 1455 mm, was analyzed. We found that the CBT was indeed significantly correlated with soil pH in our sample set. In contrast, MBT' was not correlated with MAT but had a significant correlation with the aridity index (AI), a parameter related to water availability in soils. The AI can explain 50% of the variation of the MBT', and 70% of the residuals of MAT estimated with the MBT/CBT proxy as compared to instrumentally measured MAT. We propose that, in arid settings, where water may be an ecologically limiting factor, MBT' is influenced by hydrological conditions rather than temperature. Thus, our results suggest that the combination of MBT' and CBT indices should be applied with caution in paleotemperature reconstructions in soils from dry subhumid to hyperarid environments.

  18. Evidence of moisture control on the methylation of branched glycerol dialkyl glycerol tetraethers in semi-arid and arid soils

    NASA Astrophysics Data System (ADS)

    Dang, Xinyue; Yang, Huan; Naafs, B. David A.; Pancost, Richard D.; Xie, Shucheng

    2016-09-01

    The distribution of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) is influenced by growth temperature and pH. This results in the widespread application of the brGDGT-based MBT(‧)/CBT proxy (MBT - methylation of branched tetraethers, CBT - cyclization of branched tetraethers) in terrestrial paleo-environmental reconstructions. Recently, it was shown that the amount of precipitation could also have an impact on CBT, as well as the abundance of brGDGTs relative to that of archaeal isoprenoidal (iso)GDGTs (Ri/b) and the absolute abundance of brGDGTs, potentially complicating the use of MBT/CBT as paleothermometer. However, the full influence of hydrology, and in particular soil water content (SWC), on GDGT distributions remains unclear. Here we investigated variations in the GDGT distribution across a SWC gradient (0-61%) around Qinghai Lake in the Tibetan Plateau, an arid to semiarid region in China. Our results demonstrate that SWC affects the brGDGT distribution. In particular, we show that SWC has a clear impact on the degree of methylation of C6-methylated brGDGTs, whereas C5-methylated brGDGTs are more impacted by temperature. This results in a combined SWC and temperature control on MBT‧. In this context we propose a diagnostic parameter, the IR6ME (relative abundance of C6-methylated GDGTs) index, to evaluate the applicability of brGDGT-based paleotemperature reconstructions. Using the global dataset, expanded with our own data, MBT‧ has a significant correlation with mean annual air temperature when IR6ME < 0.5, allowing for the use of MBT‧/CBT as temperature proxy. However, MBT‧ has a significant correlation with mean annual precipitation (i.e., a substantial reflection of SWC impact) when IR6ME > 0.5, implying that MBT‧ may respond to hydrological change in these regions and can be used as a proxy for MAP.

  19. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    NASA Astrophysics Data System (ADS)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  20. Branched glycerol dialkyl glycerol tetraethers in Arctic lake sediments: Sources and implications for paleothermometry at high latitudes

    NASA Astrophysics Data System (ADS)

    Peterse, Francien; Vonk, Jorien E.; Holmes, R. Max; Giosan, Liviu; Zimov, Nikita; Eglinton, Timothy I.

    2014-08-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are analyzed in different lakes of the Mackenzie (Canadian Arctic) and Kolyma (Siberian Arctic) River basins to evaluate their sources and the implications for brGDGT-based paleothermometry in high-latitude lakes. The comparison of brGDGT distributions and concentrations in the lakes with those in river suspended particulate matter, riverbank sediments, and permafrost material indicates that brGDGTs in Arctic lake sediments have mixed sources. In contrast to global observations, distributional offsets between brGDGTs in Arctic lakes and elsewhere in the catchment are minor, likely due to the extreme seasonality and short window of biological production at high latitudes. Consequently, both soil- and lake-calibrated brGDGT-based temperature proxies return sensible temperature estimates, even though the mean air temperature (MAT) in the Arctic is below the calibration range. The original soil-calibrated MBT-CBT (methylation of branched tetraethers-cyclisation of branched tetraethers) proxy generates MATs similar to those in the studied river basins, whereas using the recently revised MBT'-CBT calibration overestimates MAT. The application of the two global lake calibrations, generating summer air temperatures (SAT) and MAT, respectively, illustrates the influence of seasonality on the production of brGDGTs in lakes, as the latter overestimates actual MAT, whereas the SAT-based lake calibration accounts for this influence and consequently returns more accurate temperatures. Our results in principle support the application of brGDGT-based temperature proxies in high-latitude lakes in order to obtain long-term paleotemperature records for the Arctic, although the calibration and associated transfer function have to be selected with care.