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Sample records for capillaries critical glycerol

  1. Critical Capillary Number of Interfacial Film Displacement in a Capillary Tube

    CERN Document Server

    Yan, Changfei

    2016-01-01

    The role of surface tension and wettability in the dynamics of air-liquid interfaces during immiscible fluid displacement flows in capillary tube driven by pressure has been investigated. The contact angle and capillary number drive the force wetting processes which is controlled by the balance between the capillary and the viscous lubrication forces. The dynamic wetting condition with the critical capillary number is studied analytically and validated experimentally, which demonstrates that the critical capillary number is associated with the contact angle, slip length and capillary radius.

  2. Critical Velocity in Open Capillary Channel Flows

    Science.gov (United States)

    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.

  3. Simultaneous determination of free and total glycerol in biodiesel by capillary electrophoresis using multiple short-end injection.

    Science.gov (United States)

    Spudeit, Daniel Alfonso; Piovezan, Marcel; Dolzan, Maressa D; Vistuba, Jacqueline Pereira; Azevedo, Mônia Stremel; Vitali, Luciano; Leal Oliveira, Marcone Augusto; Oliveira Costa, Ana Carolina; Micke, Gustavo Amadeu

    2013-12-01

    A rapid method for the simultaneous determination of free glycerol (FG) and total glycerol (TG) in biodiesel by CE using a short-end multiple injection (SE/MI) configuration system is described. The sample preparation for FG involves the extraction of glycerol with water and for TG a saponification reaction is carried out followed by extraction as in the case of FG. The glycerol extracted in both cases is submitted to periodate oxidation and the iodate ions formed are measured on a CE-SE/MI system. The relevance of this study lies in the fact that no analytical procedure has been previously reported for the determination of TG (or of FG and TG simultaneously) by CE. The optimum conditions for the saponification/extraction process were 1.25% KOH and 25°C, with a time of only 5 min, and biodiesel mass in the range of 50.0-200.0 mg can be used. Multiple injections were performed hydrodynamically with negative pressure as follows: 50 mbar/3s (FG sample); 50 mbar/6s (electrolyte spacer); 50 mbar/3s (TG sample). The linear range obtained was 1.55-46.5 mg/L with R(2) > 0.99. The LOD and LOQ were 0.16 mg/L and 0.47 mg/L, respectively for TG. The method provides acceptable throughput for application in quality control and monitoring biodiesel synthesis process. In addition, it offers simple sample preparation (saponification process), it can be applied to a variety biodiesel samples (soybean, castor, and waste cooking oils) and it can be used for the determination of two key parameters related to the biodiesel quality with a fast separation (less than 30 s) using an optimized CE-SE/MI system.

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

    Science.gov (United States)

    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

  5. Sub-critical Column and Capillary Chromatography with Water as Mobile Phase and Flame Ionization Detection

    Institute of Scientific and Technical Information of China (English)

    LuFeng; LiLing; SunPeng; WuYutian

    2001-01-01

    A sub-critical chromatography (SubWC) with water as mobile phase and FID detection system is employed to separate several alcohols with high or medium polarity, with pure water as the eluent. The flow rate gets up to 50 μ1-min-1 for packed column (1 mm i.d.) and 70 μ1-min-1 for capillary (50 μm i.d.). Increasing the temperatureup to 140℃, together with temperature programming, markedly improves the separation and peak shapes within short analysis time. Sub-critical state is guaranteed.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. Is length an appropriate estimator to characterize pulmonary alveolar capillaries? A critical evaluation in the human lung

    DEFF Research Database (Denmark)

    Mühlfeld, Christian; Weibel, Ewald R.; Hahn, Ute;

    2010-01-01

    Stereological estimations of total capillary length have been used to characterize changes in the alveolar capillary network (ACN) during developmental processes or pathophysiological conditions. Here, we analyzed whether length estimations are appropriate to describe the 3D nature of the ACN. Semi...... resulted in a mean of 2,746 km (SD: 722 km). Because of the geometry of the ACN both approaches carry an unpredictable bias. The bias incurred by the design-based approach is proportional to the ratio between radius and length of the capillary segments in the ACN, the number of branching points...... and the winding of the capillaries. The model-based approach is biased because of the real noncylindrical shape of capillaries and the network structure. In conclusion, the estimation of the total length of capillaries in the ACN cannot be recommended as the geometry of the ACN does not fulfill the requirements...

  11. Glycerol hypersensitivity in a Drosophila model for glycerol kinase deficiency is affected by mutations in eye pigmentation genes.

    Directory of Open Access Journals (Sweden)

    Patrick J Wightman

    Full Text Available Glycerol kinase plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP dependent reaction. In humans, glycerol kinase deficiency results in a wide range of phenotypic variability; patients can have severe metabolic and CNS abnormalities, while others possess hyperglycerolemia and glyceroluria with no other apparent phenotype. In an effort to help understand the pathogenic mechanisms underlying the phenotypic variation, we have created a Drosophila model for glycerol kinase deficiency by RNAi targeting of dGyk (CG18374 and dGK (CG7995. As expected, RNAi flies have reduced glycerol kinase RNA expression, reduced phosphorylation activity and elevated glycerol levels. Further investigation revealed these flies to be hypersensitive to fly food supplemented with glycerol. Due to the hygroscopic nature of glycerol, we predict glycerol hypersensitivity is a result of greater susceptibility to desiccation, suggesting glycerol kinase to play an important role in desiccation resistance in insects. To evaluate a role for genetic modifier loci in determining severity of the glycerol hypersensitivity observed in knockdown flies, we performed a preliminary screen of lethal transposon insertion mutant flies using a glycerol hypersensitive survivorship assay. We demonstrate that this type of screen can identify both enhancer and suppressor genetic loci of glycerol hypersensitivity. Furthermore, we found that the glycerol hypersensitivity phenotype can be enhanced or suppressed by null mutations in eye pigmentation genes. Taken together, our data suggest proteins encoded by eye pigmentation genes play an important role in desiccation resistance and that eye pigmentation genes are strong modifiers of the glycerol hypersensitive phenotype identified in our Drosophila model for glycerol kinase deficiency.

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

    Science.gov (United States)

    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.

  13. Glycerol-induced hyperhydration

    Science.gov (United States)

    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.

  14. The Generation of Gravity-Capillary Solitary Waves by a Pressure Source Moving at a Trans-critical Speed

    CERN Document Server

    Masnadi, Naeem

    2016-01-01

    The unsteady response of a water free surface to a localized pressure source moving at constant speed $U$ in the range $0.95c_\\mathrm{min} \\lesssim U \\leq 1.02 c_\\mathrm{min}$, where $c_\\mathrm{min}$ is the minimum phase speed of linear gravity-capillary waves in deep water, is investigated through experiments and numerical simulations. This unsteady response state, which consists of a V-shaped pattern behind the source and features periodic shedding of pairs of depressions from the tips of the V, was first observed qualitatively by Diorio et al. (Phys. Rev. Let., 103, 214502, 2009) and called state III. In the present investigation, cinematic shadowgraph and refraction-based techniques are utilized to measure the temporal evolution of the free surface deformation pattern downstream of the source as it moves along a towing tank, while numerical simulations using the model equation proposed by Cho et al. (J. Fluid Mech., 672, 288-306, 2011) are used to extend the experimental results over longer times than are...

  15. Laser-based capillary polarimeter.

    Science.gov (United States)

    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

  16. Calibrating the glycerol dialkyl glycerol tetraether temperature signalin speleothems

    OpenAIRE

    Blyth, A.J.; Schouten, S.

    2013-01-01

    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 a...

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

    Science.gov (United States)

    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

  18. due to Capillary Forces

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2009-01-01

    Full Text Available We present modeling and analysis for the static behavior and collapse instabilities of doubly-clamped and cantilever microbeams subjected to capillary forces. These forces can be as a result of a volume of liquid trapped underneath the microbeam during the rinsing and drying process in fabrication. The model considers the microbeam as a continuous medium, the capillary force as a nonlinear function of displacement, and accounts for the mid-plane stretching and geometric nonlinearities. The capillary force is assumed to be distributed over a specific length underneath the microbeam. The Galerkin procedure is used to derive a reduced-order model consisting of a set of nonlinear algebraic and differential equations that describe the microbeams static and dynamic behaviors. We study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so-called pinned configuration. We calculate the pull-in length that distinguishes the free from the pinned configurations as a function of the beam thickness and gap width for both microbeams. Comparisons are made with analytical results reported in the literature based on the Ritz method for linear and nonlinear beam models. The instability problem, which brings the microbeam from a pinned to adhered configuration is also investigated. For this case, we use a shooting technique to solve the boundary-value problem governing the deflection of the microbeams. The critical microbeam length for this second instability is also calculated.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  1. Glycerol inhibition of ruminal lipolysis in vitro

    Science.gov (United States)

    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...

  2. Biohydrogen Production from Glycerol using Thermotoga spp

    NARCIS (Netherlands)

    Maru, B.T.; Bielen, A.A.M.; Kengen, S.W.M.; Constantini, M.; Medina, F.

    2012-01-01

    Given the highly reduced state of carbon in glycerol and its availability as a substantial byproduct of biodiesel production, glycerol is of special interest for sustainable biofuel production. Glycerol was used as a substrate for biohydrogen production using the hyperthermophilic bacterium, Thermot

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

    Science.gov (United States)

    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

  4. Crude glycerol combustion: Particulate, acrolein, and other volatile organic emissions

    KAUST Repository

    Steinmetz, Scott A.

    2013-01-01

    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 fossil fuel substitution. However, challenges to the use of crude glycerol as a boiler fuel include its low energy density, high viscosity, and high autoignition temperature. We have previously shown that a refractory-lined, high swirl burner can overcome challenges related to flame ignition and stability. However, critical issues related to ash behavior and the possible formation of acrolein remained. The work presented here indicates that the presence of dissolved catalysts used during the esterification and transesterification processes results in extremely large amounts of inorganic species in the crude glycerol. For the fuels examined here, the result is a submicron fly ash comprised primarily of sodium carbonates, phosphates, and sulfates. These particles report to a well-developed accumulation mode (0.3-0.7 μm diameter), indicating extensive ash vaporization and particle formation via nucleation, condensation, and coagulation. Particle mass emissions were between 2 and 4 g/m3. These results indicate that glycerol containing soluble catalyst is not suitable as a boiler fuel. Fortunately, process improvements are currently addressing this issue. Additionally, acrolein is of concern due to its toxicity, and is known to be formed from the low temperature thermal decomposition of glycerol. Currently, there is no known reliable method for measuring acrolein in sources. Acrolein and emissions of other volatile organic compounds were characterized through the use of a SUMMA canister-based sampling method followed by GC-MS analysis designed for ambient measurements. Results indicate crude glycerol combustion produces relatively small amounts of acrolein (∼15 ppbv) and other volatile organic

  5. The Lubricity of Glycerol and its Solutions

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, J.

    2016-01-01

    Glycerol has been recognised as an excellent diesel fuel and lubricant. It is a liquid that can originate from the transesterification of plant oil that also results in plant oil metyl (or ethyl) ester (biodiesel). Machine elements lubricated by glycerol show very low friction, in fact lower than...... the one predicted by hydrodynamic lubrication calculations. Addition of water to glycerol lowers the friction but increases the wear. In the present paper the lubricity (boundary lubrication performance) of glycerol and its solutions with water, ethanol and methanol is investigated. Dilution of glycerol...

  6. Freezing of capillary waves at the glass transition

    International Nuclear Information System (INIS)

    The freezing of capillary waves on glycerol surfaces is studied by in situ x-ray reflectivity measurements. A wide temperature range around the calorimetric glass transition temperature at Tg≅186 K is investigated. For T>250 K the obtained surface roughness as a function of the temperature differs significantly from the value predicted by the classical capillary waves theory. Below the temperature T≅250 K the magnitude of the roughness remains constant. Furthermore, a large hysteresis, i.e., a large difference of the roughnesses measured during cooling and heating of the sample, is observed. These findings are discussed in terms of viscosity effects

  7. Glycerol inhibition of ruminal lipolysis in vitro.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  9. 毛细管在跨临界CO2制冷空调中的数值解析%Numerical Analysis of Capillary in Trans-Critical Co2 Refrigeration Air-Condition System

    Institute of Scientific and Technical Information of China (English)

    焦玉琳; 王新华

    2012-01-01

    In view of trans-critical co2 refrigeration technology, lumped parameter is used to establish the dynamic mathematical model for the trans-critical co2 refrigeration technology according to capillary's energy conservation, mornentum conservation, mass conservation. Matlab is used to carry through calculating and solving, and condenser condensing temperature, condenser outlet temperature and evaporator inlet tem-perature are selected as output parameters. The model simulates the refrigeration system when the length and diameter of capillary change. Af- ter analyzing data and adjusting parameters, the energy efficiency ratio and refrigeration performance of the refrigeration air-condition system are both to be the best which could save time and material resources for designing and developing in industry. The model can reflect integrally the relationship of multiple-input and multiple input of trans critical co2 refrigeration system, research the influence of controlled variable pa rameters to the system performance, and build found well foundation for the system's optimization controlling and designing.%针对跨临界CO2制冷技术,根据毛细管的能量守恒、动量守恒、质量守恒,采用集中参数为跨临界CO2制冷系统建立了动态数学模型,运用Matlab进行数学计算及求解,选取了冷凝器冷凝温度、冷凝器出口温度、蒸发器入口温度作为输出参数,对毛细管长度和直径发生改变时的制冷系统进行了仿真,再对其数据进行分析与参数调整,使得制冷空调系统的能效比和制冷性能达到最佳.从而为工业设计和开发节约时间和物力.且该模型能够完整地反映跨临界CO2制冷系统的多输入多输出关系,研究控制参数对系统性能的影响,为CO2制冷系统的优化设计和优化控制打下了良好的基础.

  10. Capillary-Tube Model and Experiment of Multiphase Flow in Capillary Fringes

    Institute of Scientific and Technical Information of China (English)

    武晓峰; 唐杰; 吕贤弼

    2002-01-01

    Contamination of soil and groundwater by organic substances is causing more and more problems worldwide. Analysis of the movement and distribution of nonaqueous phase liquids (NAPLs) in subsurface domain is critical for contaminant remediation. Two-dimensional experiments were conducted in a transparent plexiglass trough (105.0 cm×70.0 cm×1.5 cm) to simulate the release and redistribution of gasoline and kerosene in porous media. The results show that before the contaminant distribution reaches equilibrium, the movement of light NAPLs (LNAPLs) can be divided into four sub-stages. After the contaminant front reaches the upper boundary of the capillary fringe, contaminant movement along the upper boundary of the capillary fringe is the primary transport process. Most of the contaminants then move into the capillary fringe except for the residual part. One-dimensional and two-dimensional capillary tube models were developed to analyze the movement of LNAPLs in the capillary fringe.

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

    OpenAIRE

    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 ex...

  12. Fermentative glycerol-free ethanol production

    NARCIS (Netherlands)

    Pronk, J.T.; Van Maris, A.J.A.; Guadalupe Medina, V.G.

    2011-01-01

    The present invention relates to a yeast cell, in particular a recombinant yeast cell, the cell lacking enzymatic activity needed for the NADH-dependent glycerol synthesis or the cell having a reduced enzymatic activity with respect to the NADH- dependent glycerol synthesis compared to its correspon

  13. Correlation spectroscopy applied to glycerol polyester spectra

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  15. Capillary-scale polarimetry for flowing streams.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  17. Microbial recycling of glycerol to biodiesel.

    Science.gov (United States)

    Yang, Liu; Zhu, Zhi; Wang, Weihua; Lu, Xuefeng

    2013-12-01

    The sustainable supply of lipids is the bottleneck for current biodiesel production. Here microbial recycling of glycerol, byproduct of biodiesel production to biodiesel in engineered Escherichia coli strains was reported. The KC3 strain with capability of producing fatty acid ethyl esters (FAEEs) from glucose was used as a starting strain to optimize fermentation conditions when using glycerol as sole carbon source. The YL15 strain overexpressing double copies of atfA gene displayed 1.7-fold increase of FAEE productivity compared to the KC3 strain. The titer of FAEE in YL15 strain reached to 813 mg L(-1) in minimum medium using glycerol as sole carbon source under optimized fermentation conditions. The titer of glycerol-based FAEE production can be significantly increased by both genetic modifications and fermentation optimization. Microbial recycling of glycerol to biodiesel expands carbon sources for biodiesel production.

  18. First level prevention instead of third level intervention-review of research to improve biocompatibility and performance of capillary membrane apheresis in critically ill patients.

    Science.gov (United States)

    Russ, Martin; Bedarf, Janis R; Grosch-Ott, Sascha; Haltern, Claudia; Rossaint, Rolf; Unger, Juliane K

    2013-06-01

    In intensive care medicine, convection-based apheresis is of growing interest. Applying extracorporeal systems in the critically ill patient can cause severe complications like nosocomial infections and bleeding, which can be worsened or even initialized by the anticoagulation protocol used. Furthermore, the filter modules (hemo- and plasmafilters) often tend to a fast blockage. A decrease in sieving performance due to membrane fouling may be tolerable for some time, but the complete blockage of high percentages of hollow fibers, which is named "clotting," often requires the immediate exchange of the filter. Extracorporeal detoxification and high clearance renal replacement regimes both require high blood flow and filtration rates. As a consequence, filter clotting and anticoagulation-associated bleeding are the most sensitive aspects in these applications. We were interested in the paradox phenomenon of the parallel occurrence of intra vitam bleeding and filter clotting in critically ill patients. Through stepwise investigations based on in vitro and animal experiments, we identified a stasis of blood flow followed by blood cell sedimentation and aggregation ("clogging") as the main factor of hollow fiber blockage in hemo- and plasma filters. As a result, various aspects which increase the risk of stasis inside the hollow fibers were investigated, for example, patient's hemorheology, configuration of an extracorporeal treatment system including interaction of catheter features with the filtration procedure, and basic therapeutic approaches such as colloidal volume substitutes and tolerated acidosis. Finally, an etiological triad for the blockage of hollow fibers due to filter clogging and consecutive filter failure was formed.

  19. Intramedullary capillary haemangioma.

    LENUS (Irish Health Repository)

    Kelleher, T

    2012-02-03

    Intramedullary capillary haemangioma is extremely rare and only four cases have been previously reported. We describe a further case, outlining the clinical, radiological, surgical and pathological features.

  20. DNA Sequencing Using capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    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

  1. Aquaporin-10 represents an alternative pathway for glycerol efflux from human adipocytes.

    Directory of Open Access Journals (Sweden)

    Umberto Laforenza

    Full Text Available 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

  2. Radiotracer and electrochemical study of the adsorption and electrocatalytic oxidation of glycerol at a platinized platinum electrode

    International Nuclear Information System (INIS)

    Adsorption and electrocatalytic oxidation of glycerol at a platinized platinum electrode have been studied in acidic medium (1 mol dm-3 HClO4). Adsorption phenomena were studied by a radiotracer method using 14C-labelled glycerol. Competitive adsorption of glycerol with chloride ions was studied using 36Cl-labelled HCl. Results of potentiostatic polarization studies were examined in the light of information obtained from tubes model. This model is the main tool used in the process of determination of parameters describing structure of the pores. The last part of the report is devoted to a brief discussion of the obtaned results. Appendix 1 contains definitions of the parameters derived from the capillary pressure curves, appendix 2 contains the input and output data of the computer program used in the calculations in a graphical form. (EG)

  3. 填充柱和毛细管亚临界水色谱-FID检测的研究%Sub-critical Column and Capillary Chromatography with Water as Mobile Phase and Flame Ionization Detection

    Institute of Scientific and Technical Information of China (English)

    陆峰; 李玲; 孙鹏; 吴玉田

    2001-01-01

    A sub-critical chromatography (SubWC) with water as mobile phase and FID detection system isemployed to separate several alcohols with high or medium polarity, with pure water as the eluent. The flow rate getsup to 50 μl@min-1 for packed column (1 mm i.d.) and 70 μl@min-1 for capillary (50 μm i.d.). Increasing the temperatureup to 140 ℃, together with temperature programming, markedly improves the separation and peak shapes withinshort analysis time. Sub-critical state is guaranteed.%本文采用纯水作流动相,在一定压力下升高系统温度以保证水处在亚临界状态,FID为检测器,分析了甲醇、异丙醇、正丁醇、2-丁醇、正戊醇、异戊醇、己醇等具有中等以上极性的醇.填充柱(1 mm i.d.)流速50μl@min-1,毛细管柱(50 μm i.d.)流速70 μl.min-1.升高温度至140℃,结合温度梯度,亚临界水可以模拟高效液相色谱常用的甲醇-水混合流动相的极性,可以显著缩短分析时间并改善峰形.分析系统保证了亚临界状态,并有望应用于无紫外吸收、含量极低的极性化合物的分析.

  4. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    Amit Sinha; B P Sharma

    2005-06-01

    High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The powders were well crystalline and contained oxygen, carbon and hydrogen as impurities. Overall purity was better than 99.9%. The yield of silver powder was better than 99%.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  7. Efficient green methanol synthesis from glycerol

    Science.gov (United States)

    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.

  8. Aminolysis Reaction of Glycerol Carbonate in Organic and Hydroorganic Medium

    OpenAIRE

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

    2012-01-01

    Aminolysis reaction of glycerol carbonate with primary amine in organic and hydroorganic media leads to the formation of two hydroxyurethane isomers and a partial decomposition of glycerol carbonate into glycerol. Aminolysis with a secondary amine promotes the condensation reaction and limits the formation of glycerol. The ratio of α versus β was determined by zgig 13C NMR. This technique permits computing the yield of α and β products in the medium. The quantity of glycerol was determined by...

  9. Intracellular glycerol influences resistance to freeze stress in Saccharomyces cerevisiae: analysis of a quadruple mutant in glycerol dehydrogenase genes and glycerol-enriched cells.

    Science.gov (United States)

    Izawa, Shingo; Sato, Machiko; Yokoigawa, Kumio; Inoue, Yoshiharu

    2004-11-01

    Glycerol is well known as a cryoprotectant similar to trehalose. However, there is little information about the effects of intracellular glycerol on the freeze-thaw stress tolerance of yeast. Through analysis of a quadruple-knockout mutant of glycerol dehydrogenase genes (ara1 Delta gcy1 Delta gre3 Delta ypr1 Delta) in Saccharomyces cerevisiae, we revealed that the decrease in glycerol dehydrogenase activity led to increased levels of intracellular glycerol. We also found that this mutant showed higher tolerance to freeze stress than wild type strain W303-1A. Furthermore, we demonstrated that intracellular-glycerol-enriched cells cultured in glycerol medium acquire tolerance to freeze stress and retain high leavening ability in dough even after frozen storage for 7 days. These results suggest the possibility of using intracellular-glycerol-enriched cells to develop better frozen dough. PMID:15127164

  10. Dramatic increase in glycerol biosynthesis upon oxidative stress in the anaerobic protozoan parasite Entamoeba histolytica.

    Directory of Open Access Journals (Sweden)

    Afzal Husain

    Full Text Available Entamoeba histolytica, a microaerophilic enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. Trophozoites of E. histolytica are exposed to a variety of reactive oxygen and nitrogen species during infection. Since E. histolytica lacks key components of canonical eukaryotic anti-oxidative defense systems, such as catalase and glutathione system, alternative not-yet-identified anti-oxidative defense strategies have been postulated to be operating in E. histolytica. In the present study, we investigated global metabolic responses in E. histolytica in response to H(2O(2- and paraquat-mediated oxidative stress by measuring charged metabolites on capillary electrophoresis and time-of-flight mass spectrometry. We found that oxidative stress caused drastic modulation of metabolites involved in glycolysis, chitin biosynthesis, and nucleotide and amino acid metabolism. Oxidative stress resulted in the inhibition of glycolysis as a result of inactivation of several key enzymes, leading to the redirection of metabolic flux towards glycerol production, chitin biosynthesis, and the non-oxidative branch of the pentose phosphate pathway. As a result of the repression of glycolysis as evidenced by the accumulation of glycolytic intermediates upstream of pyruvate, and reduced ethanol production, the levels of nucleoside triphosphates were decreased. We also showed for the first time the presence of functional glycerol biosynthetic pathway in E. histolytica as demonstrated by the increased production of glycerol 3-phosphate and glycerol upon oxidative stress. We proposed the significance of the glycerol biosynthetic pathway as a metabolic anti-oxidative defense system in E. histolytica.

  11. Distribution of glycerol dialkyl glycerol tetraether lipids in the water column of Lake Tanganyika

    NARCIS (Netherlands)

    Schouten, S.; Rijpstra, W.I.C.; Durisch-Kaiser, E.; Schubert, C.J.; Sinninghe Damste, J.S.

    2012-01-01

    We studied the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in suspended particulate matter from the water column of Lake Tanganyika (East Africa), where sediment studies had shown the applicability of the TEX86 proxy for reconstructing surface lake water temperature. GDGTs, in part

  12. Distribution of glycerol dialkyl glycerol tetraether lipids in the water column of Lake Tanganyika

    NARCIS (Netherlands)

    We studied the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in suspended particulate matter from the water column of Lake Tanganyika (East Africa), where sediment studies had shown the applicability of the TEX86 proxy for reconstructing surface lake water temperature. GDGTs, in part

  13. Capillary saturation and desaturation.

    Science.gov (United States)

    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. PMID:26764820

  14. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    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%.

  15. Catalytic glycerol steam reforming for hydrogen production

    Science.gov (United States)

    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%.

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

    Science.gov (United States)

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

    2009-06-01

    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.

  17. Gas-Filled Capillary Model

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  18. Biorefinery for Glycerol Rich Biodiesel Industry Waste.

    Science.gov (United States)

    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

  19. How Capillary Rafts Sink

    CERN Document Server

    Protiere, S; Aristoff, J; Stone, H

    2010-01-01

    We present a fluid dynamics video showing how capillary rafts sink. 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. Thanks to Archimedes principle we can easily predict whether an object sinks or floats. But what happens when several small particles are placed at an interface between two fluids. In this case surface tension also plays an important role. These particles self-assemble by capillarity and thus form what we call a "capillary raft". We show how such capillary rafts sink for varying sizes of particles and define how this parameter affects the sinking process.

  20. Derivatization in Capillary Electrophoresis.

    Science.gov (United States)

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS). PMID:27645730

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

    Science.gov (United States)

    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 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.

  2. Determining Atmospheric Pressure with a Eudiometer and Glycerol

    Science.gov (United States)

    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…

  3. Catalytic Synthesis of Glycerol tert-Butyl Ethers as Fuel Additives from the Biodiesel By-Product Glycerol

    Directory of Open Access Journals (Sweden)

    Rui Huang

    2015-01-01

    Full Text Available Glycerol is a major by-product in the biodiesel production process. Every 100 kg of biodiesel produced generates approximately 10 kg of crude glycerol. As the biodiesel industry has expanded rapidly in recent years, finding new uses of the excess crude glycerol is important. Many studies have examined alternative uses of crude glycerol. One of them is the use of glycerol derivatives, such as glycerol tert-butyl ethers as fuel additives. In this paper, the etherification kinetics of glycerol with tert-butyl alcohol to glycerol tert-butyl ethers was studied using an Amberlyst catalyst. The influences of the catalyst type and loading, reaction time, molar ratio, and temperature were investigated in detail.

  4. Biogeochemical controls on glycerol dialkyl glycerol tetraether lipid distributions in sediments characterized by diffusive methane flux

    OpenAIRE

    Weijers, J.W.H.; Lim, K.L.H.; Aquilina, A.; Sinninghe Damsté, J.S.; Pancost, R.D.

    2011-01-01

    The TEX(86) (TetraEther indeX of tetraethers consisting of 86 carbon atoms) is a proxy for sea surface temperature (SST) based on the distribution of isoprenoidal glycerol dialkyl glycerol tetraether (GDGT) membrane lipids synthesized by marine pelagic Thaumarchaeota. One of the caveats of this proxy is the production of additional GDGTs by sedimentary Euryarchaeota involved in anaerobic oxidation of methane (AOM) that occurs at deep-sea methane seeps but is also widespread in many continenta...

  5. Distribution of glycerol dialkyl glycerol tetraether lipids in the water column of Lake Tanganyika

    OpenAIRE

    2012-01-01

    We studied the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in suspended particulate matter from the water column of Lake Tanganyika (East Africa), where sediment studies had shown the applicability of the TEX86 proxy for reconstructing surface lake water temperature. GDGTs, in particular crenarchaeol, showed maximum abundance within the suboxic zone (100-180 m), suggesting that this is the preferred niche of ammonia-oxidizing Thaumarchaeota. Despite evidence for anaerobic me...

  6. Capillary permeability in adipose tissue

    DEFF Research Database (Denmark)

    Paaske, W P; Nielsen, S L

    1976-01-01

    of about 7 ml/100 g-min. This corresponds to a capillary diffusion capacity of 2.0 ml/100 g-min which is half the value reported for vasodilated skeletal muscle having approximately twice as great capillary surface area. Thus, adipose tissue has about the same capillary permeability during slight metabolic...

  7. Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.

    1992-06-01

    Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

  8. Glycerol and glycerol carbonate as ultraviscous solvents for mixture analysis by NMR

    Science.gov (United States)

    Lameiras, Pedro; Boudesocque, Leslie; Mouloungui, Zéphirin; Renault, Jean-Hugues; Wieruszeski, Jean-Michel; Lippens, Guy; Nuzillard, Jean-Marc

    2011-09-01

    NMR of weakly polar analytes in an apolar ultraviscous solvent has recently been proposed for mixture analysis as a pertinent alternative to the DOSY experiment. The present article reports the first use of glycerol and glycerol carbonate as polar solvents for the NMR analysis of a model mixture of dipeptides. This work demonstrates the high potentiality of these solvents for the analysis of mixtures made of polar and potentially bioactive compounds. Medium-sized molecules slowly reorient in glycerol and glycerol carbonate under particular temperature conditions, so that solute resonances may show spin diffusion in NOESY spectra, thus opening the way to mixture analysis. Glycerol and glycerol carbonate have turned out to be ultraviscous solvents of choice for the individualization of four structurally close mixed dipeptides: Leu-Val, Leu-Tyr, Gly-Tyr and Ala-Tyr by means of 1D and 2D NOESY experiments. Selective sample excitation and signal detection were implemented to eliminate the intense proton signals of the non-deuterated solvents. Moreover, the recording of a multiplet selective 2D NOESY-TOCSY has shown that the analytical power of NMR in highly viscous solvents is not limited to the extraction of mixture component 1D subspectra but may also yield some supplementary information about atom connectivity within components.

  9. Investigation of glycerol assimilation and cofactor metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed

    was to investigate the suitability of lactic acid bacteria as production organisms for the production of biofuels and biochemicals. Specifically, the goal was to adapt the model organism Lactococcus lactis to convert crude glycerol, to value-added fuels or chemicals. Work was divided between four main areas: life...... glycerol assimilation operon was designed based on components from known glycerol metabolizers. Three genetic elements were placed in the operon: the glycerol facilitator glpF from E. coli, the glycerol dehydrogenase dhaD from Citrobacter freundii and the dihydroxyacetone kinase dhaK also from Citrobacter...

  10. Bioconversion technologies of crude glycerol to value added industrial products

    Directory of Open Access Journals (Sweden)

    Vijay Kumar Garlapati

    2016-03-01

    Full Text Available Crude glycerol that is produced as the by-product from biodiesel, has to be effectively utilized to contribute to the viability of biodiesel. Crude glycerol in large amounts can pose a threat to the environment. Therefore, there is a need to convert this crude glycerol into valued added products using biotechnological processes, which brings new revenue to biodiesel producers. Crude glycerol can serve as a feedstock for biopolymers, poly unsaturated fatty acids, ethanol, hydrogen and n-butanol production and as a raw material for different value added industrial products. Hence, in this review we have presented different bioconversion technologies of glycerol to value added industrial products.

  11. Glycerol from biodiesel production: the new corn for dairy cattle

    Directory of Open Access Journals (Sweden)

    Shawn S Donkin

    2008-07-01

    Full Text Available Glycerol, also known as glycerin, is a colorless, odorless, hygroscopic, and sweet-tasting viscous liquid. It is a sugar alcohol with high solubility index in water and has a wide range of applications in the food, pharmaceutical, and cosmetic industries. The use of glycerol in diets for dairy cattle is not novel; however, this interest has been renewed due to the increased availability and favorable pricing of glycerol as a consequence of recent growth in the biofuels industry. Experimental evidence supports the use of glycerol as a transition cow therapy but feeding rates are low, ranging from 5 to 8 % of the diet DM. There is a paucity of research that examines the use of glycerol as a macro-ingredient in rations for lactating dairy cows. Most reports indicate a lack of effect of addition of glycerol to the diet when it replaces corn or corn starch. Recent feeding experiments with lactating dairy cows indicate replacing corn with glycerol to a level of 15% of the ration DM does not adversely effect milk production or composition. Milk production was 37.0, 36.9, 37.3, 36.4 ± 0.6 kg/d and feed intake was 24.0, 24.5, 24.6, 24.1 ± 0.5 kg/d for 0, 5, 10 and 15% glycerol treatments respectively and did not differ (P > 0.05 except for a modest reduction in feed intake during the first 7 days for the 15% glycerol treatment. Glycerol fed to dairy cattle is fermented to volatile fatty acids in the rumen and early reports indicated that glycerol is almost entirely fermented to propionate. In vitro data indicates glycerol fermentation increases the production of propionate and butyrate at the expense of acetate. Rumen microbes appear to adapt to glycerol feeding and consequently, cows fed glycerol also require an adaptation period to glycerol inclusion. Debate exists regarding the fate of glycerol in the rumen and although most reports suggest that glycerol is largely fermented in the rumen, the extent of rumen digestion may depend on level of

  12. Yeast Fps1 glycerol facilitator functions as a homotetramer.

    Science.gov (United States)

    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

  13. Nanostructure of an ionic liquid-glycerol mixture.

    Science.gov (United States)

    Murphy, Thomas; Hayes, Robert; Imberti, Silvia; Warr, Gregory G; Atkin, Rob

    2014-07-14

    The nanostructure of a 50 : 50 vol% mixture of glycerol and ethylammonium formate (EAF), a protic ionic liquid (IL), has been investigated using neutron diffraction and empirical potential structure refinement (EPSR) fits. EPSR fits reveal that the mixture is nanostructured. Electrostatic interactions between IL charge groups leads to the formation of ionic regions. These solvophobically repel cation alkyl groups which cluster together to form apolar domains. The polar glycerol molecules are preferentially incorporated into the charged domains, and form hydrogen bonds with EAF groups rather than with other glycerol molecules. However, radial distribution functions reveal that glycerol molecules pack around each other in a fashion similar to that found in pure glycerol. This suggests that a glycerol channel runs through the ionic domain of EAF. The absence of significant glycerol-glycerol hydrogen bonding indicates that glycerol molecules are able to span the polar domain, bridging EAF charge groups. Glycerol can adopt six distinct conformations. The distribution of conformers in the EAF mixture is very different to that found in the pure liquid because hydrogen bonds form with EAF rather than with other glycerol molecules, which imparts different packing constraints.

  14. Adjuvant glycerol is not beneficial in experimental pneumococcal meningitis

    Directory of Open Access Journals (Sweden)

    Wittwer Matthias

    2010-03-01

    Full Text Available Abstract Background Bacterial meningitis in children causes high rates of mortality and morbidity. In a recent clinical trial, oral glycerol significantly reduced severe neurological sequelae in paediatric meningitis caused by Haemophilus influenzae type b, and a tendency towards a benefit of adjunctive glycerol was seen in pneumococcal meningitis. Methods Here we examined the effects of glycerol in pneumococcal meningitis of infant rats and adult mice. All animals received ceftriaxone, and glycerol or placebo. Brain damage, hearing loss, and inflammatory parameters were assessed. Results Clinically and by histopathology, animals treated with glycerol or placebo did not differ. While both groups showed equally high levels of matrix metalloproteinase-9 at 24 h after infection, a significant difference in favour of glycerol was observed at 40 h after infection. However, this difference in matrix metalloproteinase-9 in late disease did not result in an improvement of histopathologic parameters. Conclusion No benefit of adjunctive glycerol was found in these models of pneumococcal meningitis.

  15. Supercapacitor carbon electrodes from pyrolyzed glycerol

    International Nuclear Information System (INIS)

    In this study pyrolyzed glycerol was explored as electrode material using a catalytic agent during pyrolysis. Here, evaporation of glycerol at high temperatures was prevented by catalyzing the formation of oligoglycerol in turn leading to carbonization above 300 °C. A one-step and tow-step pyrolysis process were developed and compared based on the suercapacitive properties of the carbon material. The pyrolysis of the glycerol was performed at 600 °C for 1 hour under nitrogen atmosphere. The product obtained was washed with 1 M HCl, and characterized using scanning electron microscopy (SEM), nitrogen adsorption (BET surface analysis), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge measurements. Carbon percent yields of 4-6% were obtained for the two different processes. The one-step process was found to have slightly higher yields. FTIR spectroscopy showed that majority of the functional groups had been removed during the pyrolysis process. SEM images show no significant difference in the surface morphology and porosity from the products of the two processes. Fabricated electrodes showed specific capacitances ranging from 0.25 Fg-“1 to 1.36 Fg-“1 through cyclic voltammetry in 1 M Li2SO4 with a sweep rate of 100 mV s”-“1 and galvonostatic cycling with a current of 1 and 5 mA from 0 to 1.2 V. These results show the potential use of carbon from pyrolysis of glycerol as active component in carbon-based supercapacitors. (author)

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

    Science.gov (United States)

    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

  17. Trapped liquid drop at the end of capillary.

    Science.gov (United States)

    Wang, Zhengjia; Yen, Hung-Yu; Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2013-10-01

    The liquid drop captured at the capillary end, which is observed in capillary valve and pendant drop technique, is investigated theoretically and experimentally. Because of contact line pinning of the lower meniscus, the lower contact angle is able to rise from the intrinsic contact angle (θ*) so that the external force acting on the drop can be balanced by the capillary force. In the absence of contact angle hysteresis (CAH), the upper contact angle remains at θ*. However, in the presence of CAH, the upper contact angle can descend to provide more capillary force. The coupling between the lower and upper contact angles determines the equilibrium shape of the captured drop. In a capillary valve, the pinned contact line can move across the edge as the pressure difference exceeds the valving pressure, which depends on the geometrical characteristic and wetting property of the valve opening. When CAH is considered, the valving pressure is elevated because the capillary force is enhanced by the receding contact angle. For a pendant drop under gravity, the maximal capillary force is achieved as the lower contact angle reaches 180° in the absence of CAH. However, in the presence of CAH, four regimes can be identified by three critical drop volumes. The lower contact angle can exceed 180°, and therefore the drop takes on the shape of a light bulb, which does not exist in the absence of CAH. The comparisons between Surface Evolver simulations and experiments are quite well. PMID:24004041

  18. Transversally periodic solitary gravity-capillary waves.

    Science.gov (United States)

    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

  19. Capillary droplets on Leidenfrost micro-ratchets

    CERN Document Server

    Marin, Alvaro G; Römer, Gertwillem R B E; Pathiraj, B; Veld, Albertus Huis in 't; Lohse, Detlef

    2012-01-01

    Leidenfrost ratchets are structures with the ability of transporting liquid droplets when heated over the critical Leidenfrost temperature. Once this temperature is reached, the droplet levitates over the surface and moves in the direction marked by the slope of the ratchet at terminal velocities around 10 cm/s. Here we provide new experiments with micron-sized ratchets, which have been produced with picosecond pulse laser ablation. In the following work, we use a simple method to measure the thrust driving droplets of capillary size over the micro-ratchets. The mechanism responsible for the force acting on the drop on superheated ratchets has been recently under debate. We extend the recently proposed 'viscous mechanism' proposed by Dupeaux et al. [Europhys. Lett., 96, 58001 (2011)] to capillary droplets and find good agreement with our measurements.

  20. Glycerol dialkyl glycerol tetraethers and TEX86 index in sinking particles in the western North Pacific

    OpenAIRE

    Yamamoto, Masanobu; Shimamoto, Akifumi; Fukuhara, Tatsuo; Tanaka, Yuichiro; Ishizaka, Joji

    2012-01-01

    Seasonal and depth variation in the flux of glycerol dialkyl glycerol tetraethers (GDGTs) and TEX86 (TEXH86 and TEXL86) values in sinking particles was examined by conducting a 21 month time-series sediment trap experiment at a mooring station (WCT-2, 39°N, 147°E) in the mid-latitude NW Pacific. The aim was to understand the sinking process of GDGTs in the water column and the preservation of the TEX86 signal in the water column and sediment surface. In the shallow trap, the sinking flux of G...

  1. Anaerobic digestion of pig manure and glycerol from biodiesel production

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh, Sumate Chaiprapat, Chaisri Suksaroj

    2015-01-01

    Full Text Available Increasing biodiesel production causes a surplus of glycerol. This work aims to investigate the crude glycerol pretreatment method and then apply the glycerol as a co-substrate with pig manure for anaerobic digestion. The optimum crude glycerol pretreatment method was acidification with 6% of H2SO4 that highest glycerol recovery was obtained with lowest cost. Co-digestions of glycerol and pig manure enhanced biogas and methane productions compared with mono-digestions. Biogas and methane productions in semi-continuous digestions were highly effected by OLR. The optimum OLR was 3.06 kg SCOD/m3 that biogas production was maintained at 3 L/d with methane composition of 72% and SCOD removal higher than 80%.

  2. Glycerol ether lipids in sediments: sources, diversity and implications

    OpenAIRE

    Liu, Xiao-Lei

    2011-01-01

    Glycerol ether lipids are prominent membrane constituents in Archaea and Bacteria that are characterized by high potential for preservation in geological settings.During the past decade they were increasingly used in molecular proxies. For example,selected glycerol dialkyl glycerol tetraethers (GDGT) are used in ratios such as the TEX86 and BIT index for reconstructing past sea surface temperature (SST) and terrestrial input, respectively. However, the distribution and structural diversity of...

  3. Fungal biotransformation of crude glycerol into malic acid.

    Science.gov (United States)

    West, Thomas P

    2015-01-01

    Malic acid production from the biodiesel coproduct crude glycerol by Aspergillus niger ATCC 9142, ATCC 10577 and ATCC 12846 was observed to occur with the highest malic acid level acid being produced by A. niger ATCC 12846. Fungal biomass production from crude glycerol was similar, but ATCC 10577 produced the highest biomass. Fungal biotransformation of crude glycerol into the commercially valuable organic acid malic acid appeared feasible.

  4. Glycerol from biodiesel production: the new corn for dairy cattle

    OpenAIRE

    Donkin, Shawn S.

    2008-01-01

    Glycerol, also known as glycerin, is a colorless, odorless, hygroscopic, and sweet-tasting viscous liquid. It is a sugar alcohol with high solubility index in water and has a wide range of applications in the food, pharmaceutical, and cosmetic industries. The use of glycerol in diets for dairy cattle is not novel; however, this interest has been renewed due to the increased availability and favorable pricing of glycerol as a consequence of recent growth in the biofuels industry. Experimental ...

  5. Borrelia burgdorferi requires glycerol for maximum fitness during the tick phase of the enzootic cycle.

    Directory of Open Access Journals (Sweden)

    Christopher J Pappas

    2011-07-01

    Full Text Available 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.

  6. Tapered capillary optics

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  8. Capillary optics for radiation focusing

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Ion guiding in alumina capillaries

    DEFF Research Database (Denmark)

    Juhász, Z.; Sulik, B.; Biri, S.;

    2009-01-01

    Transmission of a few keV impact energy Ne ions through capillaries in anodic alumina membranes has been studied with different ion counting methods using an energy dispersive electrostatic spectrometer, a multichannel plate (MCP) array and sensitive current-measurement. In the present work, we...... focus our attention to the measurements with the MCP array. The alumina capillaries were prepared by electro-chemical oxidation of aluminium foils. For the present experiments guiding of 3-6 keV Ne ions has been studied in two samples with capillary diameter of about 140 nm and 260 nm and with capillary...... length of about 15 μm. At these energies, the ions have been efficiently guided by the capillaries up to few degrees tilt angle. In this work, we compare the results obtained by the energy dispersive spectrometer to those studied by the MCP array. © 2008 Elsevier B.V. All rights reserved....

  10. Biomedical applications of capillary electrophoresis

    Science.gov (United States)

    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.

  11. The order of condensation in capillary grooves.

    Science.gov (United States)

    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

  12. Capillary fracture of soft gels

    Science.gov (United States)

    Bostwick, Joshua B.; Daniels, Karen E.

    2013-10-01

    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L∝t3/4. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent.

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

    Directory of Open Access Journals (Sweden)

    Árpád Gyéresi

    2013-02-01

    Full Text Available 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.

  14. Economic Risk Assessment of Early Stage Designs for Glycerol2Valorization in Biorefinery Concepts

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Cheali, Peam; Posada, John A.;

    2016-01-01

    A systematic methodology to critically assess and screen among early stage design alternatives was developed for the use of glycerol. Through deterministic sensitivity analysis it was found that variations in the product and feedstock prices, total production cost, fixed capital investment...... (failure to achieve a positive NPV times the consequential profit loss). It was found that the best potential options for glycerol valorization is through the production of either (i) lactic acid (9 MM$ with 63% probability of failure to achieve a positive NPV); (ii) succinic acid (14 MM$ with 76......%); or finally, (iii) 1,2-propanediol (16 MM$ with 68%). As a risk reduction strategy, a multiproduct biorefinery is suggested which is capable of switching between the production of lactic acid and succinic acid. This solution comes with increased capital investment; however, it leads to more robust NPV...

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

    Science.gov (United States)

    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.

  16. Influence of glycerol on the melting of potato starch

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Soest, J.J.G. van; Bezemer, R.C.; Wit, D. de

    1996-01-01

    The gelatinization and melting of granular and recrystallized starch have been studied in the presence of low and high levels of glycerol or water by differential scanning calorimetry. The gelatinization onset temperature is increased in the presence of glycerol, whereas the excess gelatinization en

  17. Influence of glycerol on the melting of potato starch

    NARCIS (Netherlands)

    Soest, van J.J.G.; Bezemer, R.C.; Wit, de D.; Viiegenthart, J.F.G.

    1996-01-01

    The gelatinization and melting of granular and recrystallized starch have been studied in the presence of low and high levels of glycerol or water by differential scanning calorimetry. The gelatinization onset temperature is increased in the presence of glycerol, whereas the excess gelantinization e

  18. Single crystals of V Amylose complexed with glycerol

    NARCIS (Netherlands)

    Hulleman, S.H.D.; Helbert, W.; Chanzy, H.

    1996-01-01

    Lamellar single crystals of amylose V glycerol were grown at 100°C by evaporating water from solutions of amylose in aqueous glycerol. The crystals which were square, with lateral dimensions of several micrometers, gave sharp electron diffraction patterns presenting an orthorhombic symmetry with a p

  19. Microbial community engineering for biopolymer production from glycerol

    NARCIS (Netherlands)

    Moralejo-Gárate, H.; Mar'atusalihat, E.; Kleerebezem, R.; Van Loosdrecht, M.C.M.

    2011-01-01

    In this work, the potential of using microbial community engineering for production of polyhydroxyalkanoates (PHA) from glycerol was explored. Crude glycerol is a by-product of the biofuel (biodiesel and bioethanol) industry and potentially a good substrate for bioplastic production. A PHA-producing

  20. THERMOPLASTIC STARCH-KRAFT LIGNIN-GLYCEROL BLENDS

    Science.gov (United States)

    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 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States)

    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.

  2. Bioconversion of crude glycerol feedstocks into ethanol by Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Jensen, Peter Ruhdal; Workman, Mhairi

    2012-01-01

    Glycerol, the by-product of biodiesel production, is considered as a waste by biodiesel producers. This study demonstrated the potential of utilising the glycerol surplus through conversion to ethanol by the yeast Pachysolen tannophilus (CBS4044). This study demonstrates a robust bioprocess which...... was not sensitive to the batch variability in crude glycerol dependent on raw materials used for biodiesel production. The oxygen transfer rate (OTR) was a key factor for ethanol production, with lower OTR having a positive effect on ethanol production. The highest ethanol production was 17.5 g/L on 5% (v/v) crude...... glycerol, corresponding to 56% of the theoretical yield. A staged batch process achieved 28.1 g/L ethanol, the maximum achieved so far for conversion of glycerol to ethanol in a microbial bioprocess. The fermentation physiology has been investigated as a means to designing a competitive bioethanol...

  3. Instability of the capillary bridge

    Science.gov (United States)

    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.

  4. Frequency dispersion of small-amplitude capillary waves in viscous fluids

    CERN Document Server

    Denner, Fabian

    2016-01-01

    This work presents a detailed study of the dispersion of capillary waves with small amplitude in viscous fluids using an analytically derived solution to the initial value problem of a small-amplitude capillary wave as well as direct numerical simulation. A rational parametrization for the dispersion of capillary waves in the underdamped regime is proposed, including predictions for the wavenumber of critical damping based on a harmonic oscillator model. The scaling resulting from this parametrization leads to a self-similar solution of the frequency dispersion of capillary waves that covers the entire underdamped regime, which allows an accurate evaluation of the frequency at a given wavenumber, irrespective of the fluid properties. This similarity also reveals characteristic features of capillary waves, for instance that critical damping occurs when the characteristic timescales of dispersive and dissipative mechanisms are balanced. In addition, the presented results suggest that the widely adopted hydrodyn...

  5. Differential degradation of intact polar and core glycerol dialkyl glycerol tetraether lipids upon post-depositional oxidation

    NARCIS (Netherlands)

    Lengger, S.K.; Kraaij, M.; Tjallingii, R.; Baas, M.; Stuut, J.-B.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S.

    2013-01-01

    Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids (GDGTs) are used in various proxies, such as TEX86 and the BIT index. In living organism, they contain polar head groups (intact polar lipids – IPLs). IPL GDGTs have also been detected in ancient marine sediments and it is unclear wh

  6. Branched glycerol dialkyl glycerol tetraethers in lake sediments: Can they be used as temperature and pH proxies?

    NARCIS (Netherlands)

    Blaga, C.I.; Reichart, G.J.; Schouten, S.; Lotter, A.F.; Werne, J.P.; Kosten, S.; Mazzeo, N.; Lacerot, G.; Damste, J.S.S.

    2010-01-01

    A series of surface sediments from 82 lakes of variable water depth and size was analyzed for glycerol dialkyl glycerol tetraethers (GDGTs) in order to investigate the potential of the MBT/CBT (methylation ratio/cyclization ratio of branched tetraethers) as a continental palaeothermometer in lacustr

  7. An Experimental Design Approach for the Analysis of Liquid Phase Products in Water for Hydrogenolysis of Glycerol using Immersed Solid-Phase Micro extraction

    International Nuclear Information System (INIS)

    In this study, a response surface methodology (RSM) was applied to optimize the immersed-solid-phase micro extraction (immersed-SPME) conditions for the first time using a polyacrylate (PA) coated fiber. This was to determine liquid phase compounds in water for hydrogenolysis reaction of glycerol. There are a three-factor response surface experimental design was used to evaluate the interactive effects of extraction temperature (30-70 degree Celsius), extraction time (10-30 minutes) and desorption time (2-18 minutes) on the analysis of liquid phase compounds in water for hydrogenolysis of glycerol using immersed-solid-phase micro extraction (immersed-SPME). The extraction conditions using immersed-SPME were optimized in order to achieve high enrichment of the analytes from aqueous samples. The isolated compounds from the SPME fiber were desorbed and separated on a capillary polar column of a gas chromatography-flame ionization detector (GC-FID). The extraction time and desorption time were found significant in increasing the amount of glycerol in aqueous hydrogenolysis of glycerol. Nevertheless, the effect of extraction temperature was not significant. In terms of interactions between the effects, the relation between extraction temperature and extraction time was the most significant. The optimised immersed-SPME conditions were at extraction temperature of 27 degree Celsius, extraction time of 30 minutes and 15 minutes of desorption time. Thus, the application of SPME was found to be a rapid and effective technique in the determination of glycerol and propylene glycol compounds in aqueous hydrogenolysis glycerol. (author)

  8. Surface Tension and Capillary Rise

    Science.gov (United States)

    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)

  9. Capillary Condensation in Confined Media

    CERN Document Server

    Charlaix, Elisabeth

    2009-01-01

    We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and crack tips) and to their influence on AFM imaging techniques as well as on the static and dynamic friction properties of solids (including granular heaps and sliding nanocontacts). A great attention is spent in investigating the delicate role of the surface roughness and all the difficulties involved in the reduction of the probe size to nanometric dimensions. Another major consequence of capillary condensation in nanosystems is the activation of several chemical and corrosive processes that can significantly alter the surface properties, such as dissolution/redeposition of solid materials and stress-corrosion crack propagati...

  10. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Science.gov (United States)

    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.

  11. Glycerol inhibits water permeation through Plasmodium falciparum aquaglyceroporin.

    Science.gov (United States)

    Chen, Liao Y

    2013-01-01

    Plasmodium falciparum aquaglyceroporin (PfAQP) is a multifunctional membrane protein in the plasma membrane of P. falciparum, the parasite that causes the most severe form of malaria. The current literature has established the science of PfAQP's structure, functions, and hydrogen-bonding interactions but left unanswered the following fundamental question: does glycerol modulate water permeation through aquaglyceroporin that conducts both glycerol and water? This paper provides an affirmative answer to this question of essential importance to the protein's functions. On the basis of the chemical-potential profile of glycerol from the extracellular bulk region, throughout PfAQP's conducting channel, to the cytoplasmic bulk region, this study shows the existence of a bound state of glycerol inside aquaglyceroporin's permeation pore, from which the dissociation constant is approximately 14μM. A glycerol molecule occupying the bound state occludes the conducting pore through which permeating molecules line up in single file by hydrogen-bonding with one another and with the luminal residues of aquaglyceroporin. In this way, glycerol inhibits permeation of water and other permeants through aquaglyceroporin. The biological implications of this theory are discussed and shown to agree with the existent in vitro data. It turns out that the structure of aquaglyceroporin is perfect for the van der Waals interactions between the protein and glycerol to cause the existence of the bound state deep inside the conducting pore and, thus to play an unexpected but significant role in aquaglyceroporin's functions.

  12. Flow rate limitation in open capillary channel flows.

    Science.gov (United States)

    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.

  13. Capillary fracture of soft gels.

    Science.gov (United States)

    Bostwick, Joshua B; Daniels, Karen E

    2013-10-01

    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L[proportional]t(3/4). We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent. PMID:24229192

  14. The inhibition of ice nucleators by insect antifreeze proteins is enhanced by glycerol and citrate.

    Science.gov (United States)

    Duman, J G

    2002-02-01

    Antifreeze proteins depress the freezing point of water while not affecting the melting point, producing a characteristic difference in freezing and melting points termed thermal hysteresis. Larvae of the beetle Dendroides canadensis accumulate potent antifreeze proteins (DAFPs) in their hemolymph and gut, but to achieve high levels of thermal hysteresis requires enhancers, such as glycerol. DAFPs have previously been shown to inhibit the activity of bacterial and hemolymph protein ice nucleators, however, the effect was not large and therefore the effectiveness of the DAFPs in promoting supercooling of the larvae in winter was doubtful. However, this study demonstrates that DAFPs, in combination with the thermal hysteresis enhancers glycerol (1 M) or citrate (0.5 M), eliminated the activity of hemolymph protein ice nucleators and Pseudomonas syringae ice-nucleating active bacteria, and lowered the supercooling points (nucleation temperatures) of aqueous solutions containing these ice nucleators to those of water or buffer alone. This shows that the DAFPs, along with glycerol, play a critical role in promoting hemolymph supercooling in overwintering D. canadensis. Also, DAFPs in combination with enhancers may be useful in applications which require inhibition of ice nucleators. PMID:11916110

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

    Science.gov (United States)

    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

  16. Effect Of Solid Acids In The Conversion Of Glycerol Over Ru/Bentonite Catalyst In Glycerol Hydrogenolysis Reaction

    OpenAIRE

    Noraini Hamzah; Aznira Alias; Nadia Farhana Adnan; Ainol Hayah Nadzri; Norasikin Mohamad Nordin; Mohamad Kassim; Mohd Ambar Yarmo

    2011-01-01

    Glycerol known as by-product of transesterification of vegetables oil become an important materials after some chemical modification. In this study, hydrogenolysis reaction of glycerol to 1,2-propanediol was conducted using various supported ruthenium based catalyst. The support materials used in this study are bentonite ,TiO2, Al2O3 and SiO2. All experiments were carried out at reaction condition of 150°C, hydrogen pressure 20-30 bar for 7 hours and the 20%(wt) glycerol content in distil...

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

    Science.gov (United States)

    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. Comprehensive utilization of glycerol from sugarcane bagasse pretreatment to fermentation.

    Science.gov (United States)

    Jiang, Liqun; Zheng, Anqing; Zhao, Zengli; He, Fang; Li, Haibin

    2015-11-01

    In this study, the effects of glycerol pretreatment on subsequent glycerol fermentation and biomass fast pyrolysis were investigated. The liquid fraction from the pretreatment process was evaluated to be feasible for fermentation by Paenibacillus polymyxa and could be an economic substrate. The pretreated biomass was further utilized to obtain levoglucosan by fast pyrolysis. The pretreated sugarcane bagasse exhibited significantly higher levoglucosan yield (47.70%) than that of un-pretreated sample (11.25%). The promotion could likely be attributed to the effective removal of alkali and alkaline earth metals by glycerol pretreatment. This research developed an economically viable manufacturing paradigm to utilize glycerol comprehensively and enhance the formation of levoglucosan effectively from lignocellulose. PMID:26241838

  19. Influence of glycerol on the melting of potato starch

    OpenAIRE

    Vliegenthart, J.F.G.; Soest, J.J.G. van; Bezemer, R.C.; de Wit, D.

    1996-01-01

    The gelatinization and melting of granular and recrystallized starch have been studied in the presence of low and high levels of glycerol or water by differential scanning calorimetry. The gelatinization onset temperature is increased in the presence of glycerol, whereas the excess gelatinization enthalpy is not affected. A broadening of the transition or change in shape is observed by lowering the amount of plasticizer. The increase of the melting onset temperature by the addition of glycero...

  20. Efficient synthetic protocols in glycerol under heterogeneous catalysis.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  2. Glycerol inclusion levels in corn and sunflower silages

    Directory of Open Access Journals (Sweden)

    Adriana de Souza Martins

    2014-10-01

    Full Text Available Due to the seasonal cycle of forage, the use of silage to feed animals provides nutrients throughout the year. However, its quality can be improved with the inclusion of additives and other products. Glycerol is a rich source of energy and present a high efficiency of utilization by animals. The purpose of this work was to evaluate the effect of glycerol inclusion on the chemical and fermentation characteristics of corn and sunflower silages. Two silage sources (maize and sunflower were used and four levels of glycerol inclusion (0, 15, 30 and 45% based on dry matter were carried out. The experimental design was completely randomized in a 2 x 4 factorial arrangement with five replications. The pH values and chemical composition of corn and sunflower silages were determined. In both silages there was increment of dry matter, non-fiber carbohydrates and total digestible nutrients (TDN added to a reduction of crude protein, neutral detergent fiber and acid detergent fiber due to the glycerol inclusion. The corn silage required 45% glycerol to achieve the TDN level of the sunflower silage. The glycerol addition contributed to the increase in the nutritional value, offsetting loss of quality in the ensiling process.

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

    Science.gov (United States)

    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. Baker's yeast catalyzed asymmetric reduction of methyl acetoacetate in glycerol containing systems

    Directory of Open Access Journals (Sweden)

    Adi Wolfson

    2008-09-01

    Full Text Available The asymmetric hydrogenation of methyl acetoacetate was successfully performed with baker's yeast in pure glycerol and mixtures of glycerol and water. Though yeast viability was very low after exposure to glycerol, the enzymatic activity in pure glycerol was preserved for some days. In addition, a mixture of glycerol and water combined the advantageous of each individual solvent and resulted in high catalytic performance and efficient product extraction yield

  5. Deer Frozen Semen Quality in Tris Sucrose and Tris Glucose Extender with Different Glycerol Concentrations

    OpenAIRE

    W. M. M. Nalley; R. Handarini; R.I Arifiantini; T.L. Yusuf; B. Purwantara; G. Semiadi

    2011-01-01

    In order to improve Timor deer (Cervus timorensis) frozen semen quality, the influence of sugar and glycerol concentration on semen characteristics of sperm was investigated. The semen was collected from five sexually mature Timor deer using an electroejaculator. The semen was evaluated and divided into six equal tubes and diluted with Tris sucrose glycerol 10% (TSG10); Tris sucrose glycerol 12% (TSG12); Tris sucrose glycerol 14% (TSG14); Tris glucose glycerol 10% (TGG10); Tris glucose glyce...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Baker's yeast catalyzed asymmetric reduction of methyl acetoacetate in glycerol containing systems

    OpenAIRE

    Adi Wolfson; Nisim Haddad; Chrstina Dlugy; Dorith Tavor; Yoram Shotland

    2008-01-01

    The asymmetric hydrogenation of methyl acetoacetate was successfully performed with baker's yeast in pure glycerol and mixtures of glycerol and water. Though yeast viability was very low after exposure to glycerol, the enzymatic activity in pure glycerol was preserved for some days. In addition, a mixture of glycerol and water combined the advantageous of each individual solvent and resulted in high catalytic performance and efficient product extraction yield

  8. Glycerol Affects Root Development through Regulation of Multiple Pathways in Arabidopsis

    OpenAIRE

    Jun Hu; Yonghong Zhang; Jinfang Wang; Yongming Zhou

    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 se...

  9. Reducing the Edge Chipping for Capillary End Face Grinding and Polishing

    Directory of Open Access Journals (Sweden)

    Hošek J.

    2013-05-01

    Full Text Available This paper presents results of glass capillary end face grinding and polishing by approach that reduces the edge chipping. Brittle materials have natural tendency for edge chipping what leads to beveling the sharp edges. Not beveled sharp edges on glass capillary are important for special applications like surface tension measurement of small liquid samples. We use common grinding and polishing process for capillary end face machining modified with gradual decreasing of grinding load based on the relation of the critical chipping load. Achieved surface roughness is measured using atomic force microscopy (AFM. Capillary inner edge quality is checked both with optical microscopes and electron microscope too. We achieved a non-chipped capillary inner edge with radius down to 100 nm.

  10. Impacts on oil recovery from capillary pressure and capillary heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Bognoe, Thomas

    2008-07-01

    The main conclusions drawn from this thesis are; 7 scientific papers are published on a broad variety of subjects, and describes in detail the experiments and research treated in this thesis. Scientific research has been performed, investigating the subjects of capillary pressure and capillary heterogeneities from different angles. This thesis discusses the findings in this study and aims to illustrate the benefits of the results obtained for further development of other experiments, and/or even the industrial benefits in field development. The methods for wettability alteration have developed throughout the work. From producing heterogeneous wettability alterations, the methods have improved to giving both radial and lateral uniform wettability alterations, which also remains unaltered throughout the duration of the experimental work. The alteration of wettability is dependent on initial water saturation, flow rate, aging time and crude oil composition. Capillary pressure and relative permeability curves have been measured for core plugs at different wettabilities using conventional centrifuge methods. The trends observed are mostly consistent with theory. The production mechanisms of strongly and moderately water wet chalk has been investigated. At strongly water wet conditions in fractured chalk; the flow is governed by capillary forces, showing strong impact from the fractures. At moderately water wet conditions, the impact of the fractures are absent, and a dispersed water front is observed during the displacement. The oil recovery is about the same, at the two wettabilities. Fracture crossing mechanisms at the same wettability conditions have been mapped. And the observations are consistent with those of the water floods. During strongly water wet displacement, the fracture crossing is occurring once the inlet core has reached endpoint of spontaneous imbibition. At moderately water wet conditions the fracture crossing is less abrupt, and creation of wetting

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  13. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    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. Differential degradation of intact polar and core glycerol dialkyl glycerol tetraether lipids upon post-depositional oxidation

    OpenAIRE

    Lengger, S. K.; Kraaij, M.; Tjallingii, R.; Baas, M.; Stuut, J.-B.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S.

    2013-01-01

    Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids (GDGTs) are used in various proxies, such as TEX86 and the BIT index. In living organism, they contain polar head groups (intact polar lipids – IPLs). IPL GDGTs have also been detected in ancient marine sediments and it is unclear whether or not they are fossil entities or are part of living cells. In order to determine the extent of degradation of IPL GDGTs over geological timescales, we analyzed turbidite deposits, which had...

  15. Glycerol dialkyl glycerol tetraether membrane lipids in lacustrine environments and their application as proxies for palaeoclimate reconstructions. Geologica Ultraiectina (322)

    OpenAIRE

    Blaga, C. I.

    2010-01-01

    Lacustrine sediments often contain relatively high amounts of organic matter because of limited bottom water oxygenation and relatively high sedimentation rates. The membrane lipids of Crenarchaeota, a major group of the domain Archaea, consist of isoprenoid glycerol dialkyl glycerol tetraether (GDGTs) containing cyclopentane moieties, a characteristic considered an adaptation mechanism to temperature of the membrane. Analyses of core top sediments showed that the distribution of isoprenoid G...

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

    Science.gov (United States)

    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.

  17. Current opinions of capillary leak syndrome

    Institute of Scientific and Technical Information of China (English)

    SU Jun; WANG Jin-quan; ZHANG Ying

    2012-01-01

    Capillary leak syndrome(CLS) in critically ill patients is common, and the clinical manifestations of CLS include systemic edema, hypoproteinemia, effective circulating blood volume reduction and blood concentrated.The common pathogenesy is sepsis, severe trauma, cardiopulmonary bypass and so on.CLS is divided into leakage period and recovery period usually. Clinical manifestation and treatment in different period are different in each pathophysiologic process.Although the methods of treatment are more, effective treatment measures are in shortage. More therapeutic measures are studied currently which include improvement of endothelial cell function, macromolecular colloidal solution application, continuous blood purification and so on. It is a guiding value to understand the pathological mechanism, clinical manifestations, diagnosis and treatment of the CLS.

  18. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter; Hassager, Ole

    1998-01-01

    The capillary thinning of a polymeric filament is analysed experimentally as well as by means of numerical simulation. The experimental procedure is as follows. Initially a liquid sample is kept between two cylindrical plates. Then the bottom plate is lowered under gravity to yield a given strain...

  19. Capillary Rise in a Wedge

    Science.gov (United States)

    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…

  20. Effect Of Solid Acids In The Conversion Of Glycerol Over Ru/Bentonite Catalyst In Glycerol Hydrogenolysis Reaction

    Directory of Open Access Journals (Sweden)

    Noraini Hamzah

    2011-09-01

    Full Text Available Glycerol known as by-product of transesterification of vegetables oil become an important materials after some chemical modification. In this study, hydrogenolysis reaction of glycerol to 1,2-propanediol was conducted using various supported ruthenium based catalyst. The support materials used in this study are bentonite ,TiO2, Al2O3 and SiO2. All experiments were carried out at reaction condition of 150°C, hydrogen pressure 20-30 bar for 7 hours and the 20%(wt glycerol content in distilled water. The result shows that activity of the catalyts increased following this order: Ru/SiO2< Ru/TiO2 ≈ Ru/Al2O3 < Ru/bentonite. High selectivity to 1,2-propanediol was obtained in hydrogenolysis glycerol over Ru/TiO2 (83.7% and Ru/bentonite (80.1% catalysts. Since Ru/bentonite catalyst performed better than other tested catalyst, we choose this catalyst system to investigate the effect of various solid acids (zeolite, ZrO2, Nb2O5 and amberlyst on conversion of glycerol in hydrogenolysis reaction. Addition of solid acid in hydrogenolysis glycerol had promote the activity of Ru/bentonite catalyst drastically. The result shows that the presence of zeolite make the conversion of glycerol increased to maximum from 62.8% to 81.6% compared the other solid acids. Interestingly, selectivity to 1,2-propanediol still was achieved over 80.0%. These catalysts system were characterized by XRD, XPS, BET, and TEM for obtaining some physicochemical properties of the catalysts.

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

    Science.gov (United States)

    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

  2. Dysferlin and myoferlin regulate transverse tubule formation and glycerol sensitivity.

    Science.gov (United States)

    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

    2014-01-01

    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.

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

    Science.gov (United States)

    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

  4. Digestible energy of crude glycerol for pacu and silver catfish

    Directory of Open Access Journals (Sweden)

    Rafael Ernesto Balen

    2014-01-01

    Full Text Available The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs for energy of crude glycerol for P. mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg-1 of digestible energy for Pacu and Silver catfish, respectively. In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.

  5. Source, settling and degradation of branched glycerol dialkyl glycerol tetraethers in the marine water column

    Science.gov (United States)

    Yamamoto, Masanobu; Shimamoto, Akifumi; Fukuhara, Tatsuo; Tanaka, Yuichiro

    2016-10-01

    Branched glycerol dialkyl glycerol tetraethers (branched GDGTs) are commonly found in distal marine sediments. However, their presence in the water column, source and delivery process are not fully understood. In this study, we examined seasonal and depth variation in the flux of branched GDGTs in sinking particles and underlying sediment at 39°N, 147°E in the mid-latitude NW Pacific from November 1997 to August 1999. Branched GDGTs showed synchronous variation in their sinking flux at different depths, and the variation was similar to that of lithogenic material of eolian dust origin. Their degrees of cyclization and methylation were nearly constant and bear some resemblance to those of alkaline soils. This suggests that westerly winds transport branched GDGTs to the study site via the atmosphere from continental Asia. The sinking flux of branched GDGTs was higher in 1999 than in 1998, presumably reflecting changes in the migration path of Asian dust in response to the El Niño-Southern Oscillation. Synchronous variation in branched GDGT concentrations at different depths implies rapid vertical transport of branched GDGTs to deep water with a sinking velocity exceeding 260 m d-1. The sinking flux of the branched GDGTs decreased with increasing depth, but the rate of decrease was much smaller than those of other compounds. The preservation efficiency of branched GDGTs was 3.5-6.4% of surface inputs at the water-sediment interface, which is much higher than those of isoprenoid GDGTs (1.0-1.3%) and other compounds. The branched and isoprenoid tetraether (BIT) index values were extremely low (i.e. <0.0015) in comparison with any other studies so far. The BIT values in the surface sediment were five times higher than those in sinking particles, which is attributed to the preferential preservation of branched GDGTs in oxic environments.

  6. In Situ Production of Branched Glycerol Dialkyl Glycerol Tetraethers in a Great Basin Hot Spring (USA

    Directory of Open Access Journals (Sweden)

    Chuanlun eZhang

    2013-07-01

    Full Text Available Branched glycerol dialkyl glycerol tetraethers (bGDGTs are predominantly found in soils and peat bogs. In this study, we analyzed core-bGDGTs and polar (P- 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 Core (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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    J. Menges

    2013-06-01

    Full Text Available 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.

  9. Effects of addition glycerol co-product of biodiesel in the thermophysical properties of water-glycerol solution applied as secondary coolant

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Pedro Samuel Gomes; Barbosa, Cleiton Rubens Formiga; Fontes, Francisco de Assis Oliveira [Federal University of Rio Grande do Norte, Natal, RN (Brazil). Energy Laboratory. Thermal Systems Studies Group], e-mail: cleiton@ufrnet.br

    2010-07-01

    This paper evaluates the effects of glycerol concentration on thermophysical properties of water-glycerol solution applied as a secondary coolant in refrigeration systems by expansion-indirect. The processing of triglycerides for biodiesel production generates glycerol as co-product and there are concerns of environmental and economic order on the surplus of glycerol. The addition of glycerol in water alters the colligative and thermophysical properties (melting point, mass, specific heat, thermal conductivity and dynamic viscosity). There are studies that prove the feasibility of using glycerol as an additive and this paper has the goal to verify the changes on properties compared with pure water. This comparison was made from data obtained by the software simulation and they analyzed using graphs and tables. It was shown that glycerol increases the density and dynamic viscosity, and reduces the specific heat and thermal conductivity. This behavior of water-glycerol solution is proportional to the mass concentration of glycerol and it is justified because the glycerol has low values of specific heat, thermal conductivity and high viscosity when compared with water. Despite the losses in the thermophysical properties, glycerol shows its potential application, because of the cryoscopic effect and it is a non-toxic substance at low cost. (author)

  10. Transoval trigeminal cisternography and glycerol injection in trigeminal neuralgia.

    Science.gov (United States)

    Van de Velde, C; Smeets, P; Caemaert, J; Van de Velde, E

    1989-04-01

    In a series of 25 consecutive patients suffering from essential trigeminal neuralgia, transoval glycerol injection following Håkanson was performed in order to alleviate the pain attacks. This treatment proved to be successful in 76% of the patients. No major side-effects were reported. Authors stress the importance of a precise cisternography of Meckel's cave to ascertain the correct position of the needle, before injecting the glycerol. They discuss their mode of conducting the examination in using a conventional radiologic set-up. Transoval glycerol injection is a valuable interventional radiologic procedure and has to be taken into account as an alternative treatment of essential trigeminal neuralgia, especially when current therapeutic measures have failed. PMID:2788644

  11. Potentiometric vs amperometric sensing of glycerol using glycerol dehydrogenase immobilized via layer-by-layer self-assembly

    International Nuclear Information System (INIS)

    An electrochemical biosensor for glycerol was obtained by using a novel concatenation of molecules to immobilize glycerol dehydrogenase (GlDH) on a gold electrode via layer-by-layer (LBL) self-assembly. The surface of the enzyme electrodes was characterized by cyclic voltammetry and scanning electron microscopy which confirmed the attachment of enzyme on the gold electrode with the assistance of the tethering molecules. The biosensor was assessed for its potentiometric and amperometric response to glycerol in the presence of the enzyme stimulants, ammonium sulfate and manganese chloride. The electrodes demonstrated good selectivity and reproducibility, with a amperometric response at a working voltage of 1.3 V in the 0.001 to 1 M glycerol concentration range, a 12.07 μA · M−1 sensitivity, and a 6.8 μM lower limit of detection. The average diffusion coefficient of glycerol is 8.63 × 10−6 cm2s−1 as determined by chronoamperometry. (author)

  12. A review on the performance of glycerol carbonate production via catalytic transesterification: Effects of influencing parameters

    International Nuclear Information System (INIS)

    Highlights: • Utilization of glycerol to synthesize glycerol carbonate through various routes. • Different types of carbonates and catalysts used for glycerol carbonate production via transesterification are elucidated. • Important factors influencing glycerol carbonate production performances are detailed. • Future research needs of glycerol carbonate production are proposed. - Abstract: Driven by high energy demand and environmental concerns, biodiesel as a substitute for fossil fuels is recognized to be promising renewable and clean energy. The increase in the biodiesel plant dramatically leads to the oversupply of its by-product glycerol in the biodiesel industries. Developing new industrial uses for glycerol is essential to increase the net energy and sustainability of biodiesel. Moreover, glycerol has great potential to be converted into marketable and valuable chemicals. The conversion of glycerol to glycerol carbonate (GC) has been extensively studied and transesterification of glycerol to GC has been proven to be the most promising route. Aimed to reveal the underlying mechanism of this successful conversion path, this paper reviews the chemo- and biocatalytic transesterification of glycerol with different carbonates sources. Also, a detail elucidation of the influence of the catalysts and operating conditions on the GC yield is included to provide an insight into the process. In addition, the future direction of glycerol carbonate production via catalytic transesterification is provided in this review

  13. Pulse loading of glycerol by electric explosion of wire

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  15. Exponential asymptotics and capillary waves

    OpenAIRE

    Chapman, S. J.; Vanden-Broeck, J.

    2002-01-01

    Recently developed techniques in exponential asymptotics beyond all orders are employed on the problem of potential flows with a free surface and small surface tension, in the absence of gravity. Exponentially small capillary waves are found to be generated on the free surface where the equipotentials from singularities in the flow (for example, stagnation points and corners) meet it. The amplitude of these waves is determined, and the implications are considered for many quite general flows....

  16. Capillary electrophoresis in food authenticity.

    Science.gov (United States)

    Kvasnicka, Frantisek

    2005-06-01

    Food authenticity is a term which simply refers to whether the food purchased by the consumer matches its description. False description can occur in many forms, from the undeclared addition of water or other cheaper materials, or the wrong declaration of the amount of a particular ingredient in the product, to making false statements about the source of ingredients i.e., their geographic, plant, or animal origin. The aim of this review is to summarize applications of capillary electrophoresis in food authentication.

  17. Inertial Rise in Short Capillaries

    CERN Document Server

    Shardt, Orest; Derksen, J J; Mitra, Sushanta K

    2013-01-01

    In this fluid dynamics video we show capillary rise experiments with diethyl ether in short tubes. The height of each short tube is less than the maximum height the liquid can achieve, and therefore the liquid reaches the top of the tube while still rising. Over a narrow range of heights, the ether bulges out from the top of the tube and spreads onto the external wall.

  18. Capillary Electrophoresis - Optical Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Uncovering transcriptional regulation of glycerol metabolism in Aspergilli through genome-wide gene expression data anlysis

    DEFF Research Database (Denmark)

    Salazar, Margarita Pena; Vongsangnak, Wanwipa; Panagiotou, Gianni;

    2009-01-01

    Glycerol is catabolized by a wide range of microorganisms including Aspergillus species. To identify the transcriptional regulation of glycerol metabolism in Aspergillus, we analyzed data from triplicate batch fermentations of three different Aspergilli (Aspergillus nidulans, Aspergillus oryzae...

  20. Influence of local capillary trapping on containment system effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

    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

  1. Synthesis of glycerol Carbonate from glycerol and urea using zinc-containing solid catalysts: A homogeneous reaction

    OpenAIRE

    Fujita, Shin-ichiro; Yamanishi, Yuki; Arai, Masahiko

    2013-01-01

    Zinc-containing solid catalysts (zinc oxide, smectite, hydrotalcite) and several inorganic zinc salts were used to produce glycerol carbonate from glycerol and urea under solvent-free conditions at 130℃ and at a reduced pressure of 3 kPa. The leaching of Zn species was observed to occur for the solid catalysts and the carbonate yield was shown to be correlated with the amount of zinc species dissolved into the liquid phase with a single relationship in common for all the catalysts employed. T...

  2. Progression of Diabetic Capillary Occlusion: A Model.

    Directory of Open Access Journals (Sweden)

    Xiao Fu

    2016-06-01

    Full Text Available 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.

  3. Optimized transcritical CO{sub 2} heat pumps: Performance comparison of capillary tubes against expansion valves

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Neeraj; Bhattacharyya, Souvik [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2008-05-15

    A capillary tube based CO{sub 2} heat pump is unique because of the transcritical nature of the system. The transcritical cycle has two independent parameters, pressure and temperature, unlike the subcritical cycle. In the present study, a steady state simulation model has been developed to evaluate the performance of a capillary tube based transcritical CO{sub 2} heat pump system for simultaneous heating and cooling at 73 C and 4 C, respectively against optimized expansion valve systems. Capillary tubes of various configurations having diameters of 1.4, 1.5 and 1.6 mm along with internal surface roughness of 0.001-0.003 mm have been tested to obtain the optimum design and operating conditions. Subcritical and supercritical thermodynamic and transport properties of CO{sub 2} are calculated employing a precision in-house property code. It is observed that the capillary tube system is quite flexible in response to changes in ambient temperature, almost behaving to offer an optimal pressure control. System performance is marginally better with a capillary tube at higher gas cooler exit temperature. Capillary tube length turns out to be the critical parameter that influences system optimum conditions. A novel nomogram has been developed that can be employed as a guideline to select the optimum capillary tube. (author)

  4. Direct measurement of the surface dynamics of supercooled liquid-glycerol by optical scanning a film

    Institute of Scientific and Technical Information of China (English)

    Zhang Fang; Zhang Guo-Feng; Dong Shuang-Li; Sun Jian-Hu; Chen Rui-Yun; Xiao Lian-Tuan; Jia Suo-Tang

    2009-01-01

    The surface dynamics of supercooled liquid-glycerol is studied by scanning the thickness of the glycerol film with single photon detection. Measurements are performed at room temperature well above the glycerol's glass transition temperature. It is shown that the surface dynamics of the glycerol film is very sensitive to the temperature. The linear relationship between the thickness of the film and the viscosity predicted by the Vogel-Fulcher-Tammann-Hesse (VFTH) law is also presented experimentally.

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

    Science.gov (United States)

    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.

  6. Reforming of methanol and glycerol in supercritical water

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Assink, D.; Heeres, H. J.

    2011-01-01

    Reforming of pure glycerol, crude glycerin, and methanol (pure and in the presence of Na(2)CO(3)) in supercritical water was investigated. Continuous experiments were carried out at temperatures between 450 and 650 degrees C, residence times between 6 and 173 s, and feed concentrations of 3-20 wt%.

  7. Comment on ``Fast dynamics of glass-forming glycerol''

    Science.gov (United States)

    Ngai, K. L.; Roland, C. M.

    1997-02-01

    The coupling model predicts the existence of a prominent fast α process at times Wuttke, Petry, Coddens, and Fujara (WPCF) [Phys. Rev. E 52, 4026 (1995)], leading to the conclusion that the fast α process is indeed quite weak therein. Thus, the coupling model predictions are fully consistent with the glycerol data, notwithstanding WPCF's statement to the contrary.

  8. Coronary artery bypass with glycerol-preserved saphenous vein allografts

    OpenAIRE

    Bortolotti, Uberto; Casarotto, Dino; Frugoni, Carlo; De Mozzi, Pierluigi; Thiene, Gaetano; Gallucci, Vincenzo

    1981-01-01

    Over a 2-year period, 19 patients whose autologous saphenous veins were either unsuitable or unavailable underwent myocardial revascularization with saphenous vein allografts (SVAs) at our institution. All SVAs had been preserved in 98% glycerol at room temperature for at least 3 weeks (average, 7 weeks); before use, they were rinsed with saline and antibiotic solution.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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...

  12. Glycerol reforming and methanol synthesis for the production of renewable methanol

    NARCIS (Netherlands)

    van Bennekom, Joost Gerardus

    2013-01-01

    De productie van biodiesel is flink toegenomen in het eerste decennium van de 21ste eeuw. Bij de productie van 100 kg biodiesel komt ongeveer 10 kg aan glycerol vrij, wat heeft geleid tot een sterk gestegen glycerol aanbod. Een mogelijkheid om wat met de glycerol te doen, is het omzetten van glycero

  13. Glycerol fermentation to hydrogen by Thermotoga maritima: Proposed pathway and bioenergetic considerations

    NARCIS (Netherlands)

    Maru, B.T.; Bielen, A.A.M.; Constanti, M.; Medina, F.; Kengen, S.W.M.

    2013-01-01

    The production of biohydrogen from glycerol, by the hyperthermophilic bacterium Thermotoga maritima DSM 3109, was investigated in batch and chemostat systems. T. maritima converted glycerol to mainly acetate, CO2 and H2. Maximal hydrogen yields of 2.84 and 2.41 hydrogen per glycerol were observed fo

  14. Frequency dispersion of small-amplitude capillary waves in viscous fluids.

    Science.gov (United States)

    Denner, Fabian

    2016-08-01

    This work presents a detailed study of the dispersion of capillary waves with small amplitude in viscous fluids using an analytically derived solution to the initial value problem of a small-amplitude capillary wave as well as direct numerical simulation. A rational parametrization for the dispersion of capillary waves in the underdamped regime is proposed, including predictions for the wave number of critical damping based on a harmonic-oscillator model. The scaling resulting from this parametrization leads to a self-similar solution of the frequency dispersion of capillary waves that covers the entire underdamped regime, which allows an accurate evaluation of the frequency at a given wave number, irrespective of the fluid properties. This similarity also reveals characteristic features of capillary waves, for instance that critical damping occurs when the characteristic time scales of dispersive and dissipative mechanisms are balanced. In addition, the presented results suggest that the widely adopted hydrodynamic theory for damped capillary waves does not accurately predict the dispersion when viscous damping is significant, and an alternative definition of the damping rate, which provides consistent accuracy in the underdamped regime, is presented. PMID:27627395

  15. Modeling and Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects in Glycerol Continuous Fermentation

    Directory of Open Access Journals (Sweden)

    Zhaohua Gong

    2012-01-01

    Full Text Available Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an extension of the state space method, an improved genetic algorithm is then constructed to solve the parameter identification model. An illustrative numerical example shows the appropriateness of the proposed model and the validity of optimization algorithm. Since it is difficult to measure the concentrations of intracellular substances, a quantitative robustness analysis method is given to infer whether the model is plausible for the intracellular substances. Numerical results show that the proposed model is of good robustness.

  16. The use of glycerol-preserved corneas in the developing world

    Directory of Open Access Journals (Sweden)

    Feilmeier Michael

    2010-01-01

    Full Text Available Corneal opacity is the third leading cause of blindness in the developing world and encompasses a wide variety of infectious, inflammatory and degenerative eye diseases. Most caes of corneal blindness are treatable with partial or full-thickness keratoplasty, provided adequate corneal tissue and surgical skill is available. However, access to sight-restoring keratoplasty in developing countries is limited by the lack of developed eye banking networks and a critical shortage of tissue suitable for transplantation. Beyond the developed world, corneal transplantation using fresh corneal tissue (FCT is further hindered by unreliable storage and transportation facilities, unorganized distribution networks, the cost-prohibitive nature of imported tissue, unreliable compliance with medications and follow-up instructions and inadequate health and education services. Glycerol-preserved corneas overcome many of these limitations inherent to the use of FCT. As surgical innovation in lamellar corneal surgery expands the potential use of acellular corneal tissue, long-term preservation techniques are being revisited as a way to increase availability of corneal tissue to corneal surgeons throughout the developing world. Herein, we discuss the advantages of using and the applications for glycerol-preserved corneal tissue throughout the developing world.

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

    Science.gov (United States)

    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.

  18. A Simulation of Blood Cells in Branching Capillaries

    CERN Document Server

    Isfahani, Amir H G; Freund, Jonathan B

    2008-01-01

    The multi-cellular hydrodynamic interactions play a critical role in the phenomenology of blood flow in the microcirculation. A fast algorithm has been developed to simulate large numbers of cells modeled as elastic thin membranes. For red blood cells, which are the dominant component in blood, the membrane has strong resistance to surface dilatation but is flexible in bending. Our numerical method solves the boundary integral equations built upon Green's functions for Stokes flow in periodic domains. This fluid dynamics video is an example of the capabilities of this model in handling complex geometries with a multitude of different cells. The capillary branch geometries have been modeled based upon observed capillary networks. The diameter of the branches varies between 10-20 mum. A constant mean pressure gradient drives the flow. For the purpose of this fluid dynamics video, the red blood cells are initiated as biconcave discs and white blood cells and platelets are initiated as spheres and ellipsoids resp...

  19. Capillary pumped loop body heat exchanger

    Science.gov (United States)

    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.

  20. Measurement of Liquid Viscosities in Tapered or Parabolic Capillaries.

    Science.gov (United States)

    Ershov; Zorin; Starov

    1999-08-01

    The possibility of using tapered or parabolic capillaries for measurement of liquid viscosities is investigated both experimentally and theoretically. It is demonstrated that even small deviations in capillary radius from a constant value may substantially affect measurement results. Equations are derived which allow correct analysis of the measurement results in tapered or parabolic capillaries. The following cases are analyzed: a water imbibition into a tapered or parabolic capillary and displacement of one liquid by another immiscible liquid in tapered or parabolic capillaries. Two possibilities are considered: (a) the narrow end of the capillary as capillary inlet and (b) the wide end of the capillary as capillary inlet. Copyright 1999 Academic Press.

  1. Analysis of Small Ions with Capillary Electrophoresis.

    Science.gov (United States)

    Aulakh, Jatinder Singh; Kaur, Ramandeep; Malik, Ashok Kumar

    2016-01-01

    Small inorganic ions are easily separated through capillary electrophoresis because they have a high charge-to-mass ratio and suffer little from some of the undesired phenomenon affecting higher molecular weight species like adsorption to the capillary wall, decomposition, and precipitation. This chapter is focused on the analysis of small ions other than metal ions using capillary electrophoresis. Methods are described for the determination of ions of nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, and iodine. PMID:27645739

  2. A New Conductivity Detector for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new conductivity detector for capillary electrophoresis consisting of an electrochemical cell and a conductive meter was developed. In the cell, the microelectrode and capillary were inserted through the cell wall and fixed by screws and sealing ring, the ends of microelectrode and capillary were located by a guide with two cross holes. LOD for K+ was 1.5×10-5 mol/L.

  3. Serum proteins analysis by capillary electrophoresis

    OpenAIRE

    Uji, Yoshinori; Okabe, Hiroaki

    2001-01-01

    The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of...

  4. Slope wavenumber spectrum models of capillary and capillary-gravity waves

    Institute of Scientific and Technical Information of China (English)

    贾永君; 张杰; 王岩峰

    2010-01-01

    Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using th...

  5. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter

    1999-01-01

    The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then......, the bottom plate is lowered under gravity to produce a specified strain. The sample is thereby stretched into a filament. Provided the filament is sufficiently long, surface tension will induce a thinning of the filament until breakup in finite time. The numerical simulations are performed with a Lagrangian...

  6. Electromigration dispersion in Capillary Electrophoresis

    CERN Document Server

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

    2012-01-01

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

  7. Capillary electrophoresis theory and practice

    CERN Document Server

    Grossman, Paul D

    1992-01-01

    This book is designed to be a practical guide, used by wide audience, including those new to CE, those more experienced, routine users, those interested in technology development, and those involved with applications research. References have been emphasized to allow the reader to explore the detailed specifics and theoretical foundations.This book draws together the rapidly evolving, diverse, and multidisciplinary subject of capillary electrophoresis (CE). It is designed as a practical guide to be used by a wide audience, including those new to CE as well as more experienced users. T

  8. Effects of Glycerol in the Refolding and Unfolding of Creatine Kinase

    Institute of Scientific and Technical Information of China (English)

    欧文斌; 朴龙斗; 孟凡国; 周海梦

    2002-01-01

    The effects of glycerol in the refolding, reactivation, unfolding, and inactivation of guanidine- denatured creatine kinase were studied by observing the fluorescence emission spectra and the circular dichroism spectra, and by recovery and inactivation of enzymatic activity and aggregation. The results show that low concentrations of glycerol (<25%) improve the refolding yields of creatine kinase, but high glycerol concentrations decrease its recovery. Glycerol favors the secondary structural formation and inhibits aggregation of creatine kinase as proline does. These systematic observations further support the suggestion that low concentrations of glycerol possibly play a chaperone role in the refolding of creatine kinase. In addition, glycerol reduces the inactivation and unfolding rate of creatine kinase, increases the change in transition free energy of unfolding (ΔΔGu) and stabilizes its active conformation relative to the partially unfolded state with no glycerol. In the presence of glycerol, the inactivation and unfolding dynamics of creatine kinase are related to glycerol concentrations. Glycerol blocks the exposure of hydrophobic areas and the dissociation of dimers, and protects creatine kinase against guanidine denaturation in a concentration-dependent manner. This study suggests that glycerol as an energy substrate for metabolism and organic components in vivo, assists correct protein folding, maintains adequate rates of enzymatic catalysis and stabilizes the protein secondary and tertiary conformations.

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

    Directory of Open Access Journals (Sweden)

    Kristopher Burkewitz

    Full Text Available 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

  10. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    Science.gov (United States)

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

    The term nonaqueous capillary electrophoresis (NACE) commonly refers to capillary electrophoresis with purely nonaqueous background electrolytes (BGE). Main advantages of NACE are the possibility to analyze substances with very low solubility in aqueous media as well as separation selectivity that can be quite different in organic solvents (compared to water)-a property that can be employed for manipulation of separation selectivities. Mass spectrometry (MS) has become more and more popular as a detector in CE a fact that applies also for NACE. In the present chapter, the development of NACE-MS since 2004 is reviewed. Relevant parameters like composition of BGE and its influence on separation and detection in NACE as well as sheath liquid for NACE-MS are discussed. Finally, an overview of the papers published in the field of NACE-MS between 2004 and 2014 is given. Applications are grouped according to the field (analysis of natural products, biomedical analysis, food analysis, analysis of industrial products, and fundamental investigations). PMID:27645734

  11. Atomic Force Controlled Capillary Electrophoresis

    Science.gov (United States)

    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.

  12. Cryogenic Capillary Screen Heat Entrapment

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  14. Diagnostics of a high current capillary discharge

    International Nuclear Information System (INIS)

    We have demonstrated that thin (10 to 25 μm diameter) capillaries can be fabricated in suitably configured insulators for use in pulse power machines. Large currents can be used to heat these capillaries which produce photons with an energies greater than 1 keV

  15. Pulmonary capillary haemangiomatosis in a premature infant

    International Nuclear Information System (INIS)

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  16. Pulmonary capillary haemangiomatosis in a premature infant

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cicero J.T.A.; Massie, John; Mandelstam, Simone A. [University of Melbourne, Royal Children' s Hospital, Parkville, VIC (Australia)

    2005-06-01

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  17. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gholami, Zahra, E-mail: zahra.gholami@petronas.com.my [Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my; Gholami, Fatemeh, E-mail: fgholami59@gmail.com [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus,14300 Nibong Tebal, Penang (Malaysia); Vakili, Mohammadtaghi, E-mail: farshid3601@gmail.com [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    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%.

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

    International Nuclear Information System (INIS)

    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%

  20. PROPERTIES OF THERMO-MOLDED GLUTEN/GLYCEROL/SILICA COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Yi-hu Song; Qiang Zheng; Zheng-zheng Lai

    2008-01-01

    Environmentally friendly thermosetting composites were successfully prepared by conventional blending wheat gluten as matrix.glycerol as plasticizer and silica as filler followed by thermo-molding of the mixture at 120℃.The strong interfacial interaction between silica particles and gluten proteins leaded to an increase in storage modulus and a decrease in loss factor as revealed by dynamic mechanical analysis.The moisture absorption and elongation at break decrease while Young's modulus and tensile strength increase with increasing silica content from 0 to 10 wt%.However,the moisture absorption and mechanical properties show discontinuous changes at a silica content of 6 wt%.The glycerol content also has a marked influence on the moisture absorption and mechanical properties of the composites with a constant gluten-to-silica ratio.

  1. Biomass Pretreatment using Ionic Liquid and Glycerol Mixtures

    Science.gov (United States)

    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

  2. Capillary Zone Electrophoresis-Mass Spectrometry of Intact Proteins.

    Science.gov (United States)

    Domínguez-Vega, Elena; Haselberg, Rob; Somsen, Govert W

    2016-01-01

    Capillary electrophoresis (CE) coupled with mass spectrometry (MS) has proven to be a powerful analytical tool for the characterization of intact proteins. It combines the high separation efficiency, short analysis time, and versatility of CE with the mass selectivity and sensitivity offered by MS detection. This chapter focuses on important practical considerations when applying CE-MS for the analysis of intact proteins. Technological aspects with respect to the use of CE-MS interfaces and application of noncovalent capillary coatings preventing protein adsorption are treated. Critical factors for successful protein analysis are discussed and four typical CE-MS systems are described demonstrating the characterization of different types of intact proteins by CE-MS. These methodologies comprise the use of sheath-liquid and sheathless CE-MS interfaces, and various types of noncovalent capillary coatings allowing efficient and reproducible protein separations. The discussion includes the analysis of lysozyme-drug conjugates and the therapeutic proteins human growth hormone, human interferon-β-1a, and human erythropoietin. PMID:27473479

  3. Evaporation Limited Radial Capillary Penetration in Porous Media.

    Science.gov (United States)

    Liu, Mingchao; Wu, Jian; Gan, Yixiang; Hanaor, Dorian A H; Chen, C Q

    2016-09-27

    The capillary penetration of fluids in thin porous layers is of fundamental interest in nature and various industrial applications. When capillary flows occur in porous media, the extent of penetration is known to increase with the square root of time following the Lucas-Washburn law. In practice, volatile liquid evaporates at the surface of porous media, which restricts penetration to a limited region. In this work, on the basis of Darcy's law and mass conservation, a general theoretical model is developed for the evaporation-limited radial capillary penetration in porous media. The presented model predicts that evaporation decreases the rate of fluid penetration and limits it to a critical radius. Furthermore, we construct a unified phase diagram that describes the limited penetration in an annular porous medium, in which the boundaries of outward and inward liquid are predicted quantitatively. It is expected that the proposed theoretical model will advance the understanding of penetration dynamics in porous media and facilitate the design of engineered porous architectures. PMID:27583455

  4. MACROSCOPIC KINETIC MODELS OF GLYCEROL BATCH FERMENTATION WITH OSMOTOLERANT YEAST

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    l introductionGlycerol production by fermentation has beenwidely investigated to meet the great commercialdemand in last decades and osmotolerant yeast wasthe microorganism studied most. To analyze thefermentation process more efficiently, a kinetic modelshould be established but little works about it werereported because of its complicated metabolism ofglycerol [1-3]. Batch fermentation experiment showedthat low glucose concentration in the latterfermentation stage resulted in decrease in both glucoseconsu...

  5. Glycerol Monolaurate Inhibits Virulence Factor Production in Bacillus anthracis

    OpenAIRE

    Vetter, Sara M; Schlievert, Patrick M.

    2005-01-01

    Anthrax, caused by Bacillus anthracis, has been brought to the public's attention because of the 2001 bioterrorism attacks. However, anthrax is a disease that poses agricultural threats in the United States as well as human populations in Europe, China, Africa, and Australia. Glycerol monolaurate (GML) is a compound that has been shown to inhibit exotoxin production by Staphylococcus aureus and other gram-positive bacteria. Here, we study the effects of GML on growth and toxin production in B...

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

    Science.gov (United States)

    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 (crystallisation and reorganisation effects, which give rise to pronounced out-of phase components of the specific heat at higher temperatures. PMID:26723689

  7. Protease activation in glycerol-based deep eutectic solvents

    OpenAIRE

    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 exa...

  8. Bio-Propane from glycerol for biogas addition

    Energy Technology Data Exchange (ETDEWEB)

    Brandin, Jan; Hulteberg, Christian; Liljegren Nilsson, Andreas (Biofuel-Solution AB, Malmoe (Sweden))

    2008-11-15

    In this report, the technical and economical feasibility to produce higher alkanes from bioglycerol has been investigated. The main purpose of producing this kind of chemicals would be to replace the fossil LPG used in upgraded biogas production. When producing biogas and exporting it to the natural gas grid, the Wobbe index and heating value does not match the existing natural gas. Therefore, the upgraded biogas that is put into the natural gas grid in Sweden today contains 8-10 vol-% of LPG. The experimental work performed in association to this report has shown that it is possible to produce propane from glycerol. However, the production of ethane from glycerol may be even more advantageous. The experimental work has included developing and testing catalysts for several intermediate reactions. The work was performed using different micro-scale reactors with a liquid feed rate of 18 g/h. The first reaction, independent on if propane or ethane is to be produced, is dehydration of glycerol to acrolein. This was showed during 60 h on an acidic catalyst with a yield of 90%. The production of propanol, the second intermediate to producing propane, was shown as well. Propanol was produced both using acrolein as the starting material as well as glycerol (combining the first and second step) with yields of 70-80% in the first case and 65-70% in the second case. The propanol produced was investigated for its dehydration to propene, with a yield of 70-75%. By using a proprietary, purposely developed catalyst the propene was hydrogenated to propane, with a yield of 85% from propanol. The formation of propane from glycerol was finally investigated, with an overall yield of 55%. The second part of the experimental work performed investigated the possibilities of decarbonylating acrolein to form ethane. This was made possible by the development of a proprietary catalyst which combines decarbonylation and water-gas shift functionality. By combining these two functionalities, no

  9. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    DEFF Research Database (Denmark)

    Parsons, M.T.; Westh, Peter; Davies, J.V.;

    2001-01-01

    The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...

  10. Influence of local capillary trapping on containment system effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

    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

  11. Numerical Simulation of Unsteady Blood Flow through Capillary Networks.

    Science.gov (United States)

    Davis, J M; Pozrikidis, C

    2011-08-01

    A numerical method is implemented for computing unsteady blood flow through a branching capillary network. The evolution of the discharge hematocrit along each capillary segment is computed by integrating in time a one-dimensional convection equation using a finite-difference method. The convection velocity is determined by the local and instantaneous effective capillary blood viscosity, while the tube to discharge hematocrit ratio is deduced from available correlations. Boundary conditions for the discharge hematocrit at divergent bifurcations arise from the partitioning law proposed by Klitzman and Johnson involving a dimensionless exponent, q≥1. When q=1, the cells are partitioned in proportion to the flow rate; as q tends to infinity, the cells are channeled into the branch with the highest flow rate. Simulations are performed for a tree-like, perfectly symmetric or randomly perturbed capillary network with m generations. When the tree involves more than a few generations, a supercritical Hopf bifurcation occurs at a critical value of q, yielding spontaneous self-sustained oscillations in the absence of external forcing. A phase diagram in the m-q plane is presented to establish conditions for unsteady flow, and the effect of various geometrical and physical parameters is examined. For a given network tree order, m, oscillations can be induced for a sufficiently high value of q by increasing the apparent intrinsic viscosity, decreasing the ratio of the vessel diameter from one generation to the next, or by decreasing the diameter of the terminal vessels. With other parameters fixed, oscillations are inhibited by increasing m. The results of the continuum model are in excellent agreement with the predictions of a discrete model where the motion of individual cells is followed from inlet to outlet.

  12. Comparison of CO2 trapping in highly heterogeneous reservoirs with Brooks-Corey and van Genuchten type capillary pressure curves

    CERN Document Server

    Gershenzon, Naum I; Dominic, David F; Mehnert, Edward; Okwen, Roland T

    2015-01-01

    Geological heterogeneities essentially affect the dynamics of a CO2 plume in subsurface environments. Previously we showed how the dynamics of a CO2 plume is influenced by the multi-scale stratal architecture in deep saline reservoirs. The results strongly suggest that representing small-scale features is critical to understanding capillary trapping processes. Here we present the result of simulation of CO2 trapping using two different conventional approaches, i.e. Brooks-Corey and van Genuchten, for the capillary pressure curves. We showed that capillary trapping and dissolution rates are very different for the Brooks-Corey and van Genuchten approaches when heterogeneity and hysteresis are both represented.

  13. Effects of Capillary Forces and Adsorption on Reserves Distribution

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1996-01-01

    The purpose of this study is to evaluate the effects of capillary forces and adsorption on the distribution of a hydrocarbon mixture in an oil-gas-condensate reservoir. These effects consist in the precipitation of the liquid phase in thin pores and on the internal surface of the reservoir rock....... To estimate the amount of the dispersed liquid condensate, analytical methods based on the generalization of the Kelvin equation and on the potential theory of adsorption have been developed. Sample calculations show significant role of adsorption, especially, in the neighborhood of the critical point...

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

    Science.gov (United States)

    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

  15. Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

    KAUST Repository

    Selembo, Priscilla A.

    2009-12-15

    The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H2/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H 2/mol-glycerol (43 mL H2/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste. © 2009 Wiley Periodicals, Inc.

  16. Enhancement of glycerol utilization ability of Ralstonia eutropha H16 for production of polyhydroxyalkanoates.

    Science.gov (United States)

    Fukui, Toshiaki; Mukoyama, Masaharu; Orita, Izumi; Nakamura, Satoshi

    2014-09-01

    Ralstonia eutropha H16 is a well-studied bacterium with respect to biosynthesis of polyhydroxyalkanoates (PHAs), which has attracted attentions as biodegradable bio-based plastics. However, this strain shows quite poor growth on glycerol of which bulk supply has been increasing as a major by-product of biodiesel industries. This study examined enhancement of glycerol assimilation ability of R. eutropha H16 by introduction of the genes of aquaglyceroporin (glpF) and glycerol kinase (glpK) from Escherichia coli. Although introduction of glpFK Ec into the strain H16 using a multi-copy vector was not successful, a recombinant strain possessing glpFK Ec within the chromosome showed much faster growth on glycerol than H16. Further analyses clarified that weak expression of glpK Ec alone allowed to establish efficient glycerol assimilation pathway, indicating that the poor growth of H16 on glycerol was caused by insufficient kination activity to glycerol, as well as this strain had a potential ability for uptake of extracellular glycerol. The engineered strains expressing glpFK Ec or glpK Ec produced large amounts of poly[(R)-3-hydroxybutyrate] [P(3HB)] from glycerol with much higher productivity than H16. Unlike other glycerol-utilizable wild strains of R. eutropha, the H16-derived engineered strains accumulated P(3HB) with no significant decrease in molecular weights on glycerol, and the polydispersity index of the glycerol-based P(3HB) synthesized by the strains expressing glpFK Ec was lower than those by the parent strains. The present study demonstrated possibility of R. eutropha H16-based platform for production of useful compounds from inexpensive glycerol.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramanan, Keerthi P.; Boatman, Judy J.; Taconi, Katherine A. [Alabama Univ., Huntsville, AL (United States). Dept. of Chemical and Materials Engineering; Kurniawan, Yogi; Bothun, Geoffrey D. [Rhode Island Univ., Kingston, RI (United States). Dept. of Chemical Engineering; Scholz, Carmen [Alabama Univ., Huntsville, AL (United States). Dept. of Chemistry

    2012-02-15

    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. (orig.)

  19. Dielectric and specific heat relaxations in vapor deposited glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Kasina, A., E-mail: angeline.kasina@fys.kuleuven.be, E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M., E-mail: angeline.kasina@fys.kuleuven.be, E-mail: wubbenhorst@fys.kuleuven.be [Department of Physics and Astronomy, Soft Matter and Biophysics Section, KU Leuven, Leuven (Belgium)

    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

  20. Effective heterogeneous transition metal glycerolates catalysts for one-step biodiesel production from low grade non-refined Jatropha oil and crude aqueous bioethanol

    OpenAIRE

    Pak-Chung Lau; Tsz-Lung Kwong; Ka-Fu Yung

    2016-01-01

    The utilization of bioethanol as the alcohol source for biodiesel production is more environmentally advantageous over methanol owing to its lower toxicity, lower flammability and its sustainable supply from renewable agricultural resources. However, as the presence of water in crude bioethanol is the critical factor limiting the biodiesel production process, the energy-intensive and costly purification of bioethanol is necessary for biodiesel application. Manganese glycerolate (MnGly) is rep...

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

    Science.gov (United States)

    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

  2. Bioconversion of glycerol for bioethanol production using isolated Escherichia coli SS1

    Directory of Open Access Journals (Sweden)

    Sheril Norliana Suhaimi

    2012-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  4. Gas-phase dehydration of glycerol over thermally-stable SAPO-40 catalyst

    OpenAIRE

    Lourenço, J. P.; Fernandes, A; Bértolo, R. A.; Ribeiro, M. F.

    2015-01-01

    SAPO-40 was used as catalyst for the gas-phase dehydration of glycerol towards acrolein. At 350 ºC the catalyst attained full conversion of glycerol with a negligible deactivation in the first 48 h, a glycerol conversion above 50 % after 120 h on stream and a nearly constant selectivity to acrolein above 70%. This catalyst proved to be highly resistant under the experimental conditions used and can be regenerated without loss of activity or significant structural damage. The compa...

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

    Science.gov (United States)

    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

  6. Substrate specificity and transport properties of the glycerol facilitator of Escherichia coli.

    OpenAIRE

    Heller, K B; Lin, E C; Wilson, T H

    1980-01-01

    The specificity of the glycerol facilitator (glpF) of Escherichia coli was studied with an osmotic method. This transport system allowed the entry of polyols (glycerol and erythritol), pentitols, and hexitols. The analogous sugars were not transported. However, urea, glycine, and DL-glyceraldehyde could use this pathway to enter the cell. The glpF protein allowed the rapid efflux of preequilibrated xylitol. Glycerol surprisingly did not inhibit the uptake of xylitol, and xylitol only slightly...

  7. Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

    OpenAIRE

    Liangjun Zhu; Lei Yang; Sijia Min; Haiping Zhang; Lianxia Deng; Mingying Yang

    2011-01-01

    An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol) sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition ...

  8. Pharmacological investigations of Punica granatum in glycerol-induced acute renal failure in rats

    OpenAIRE

    Amrit Pal Singh; Amteshwar Jaggi Singh; Nirmal Singh

    2011-01-01

    Objective : The present study was designed to investigate the ameliorative potential and possible mechanism of hydroalcoholic extract of flowers of P. granatum in glycerol-induced acute renal failure (ARF) in rats. Materials and Methods : The rats were subjected to rhabdomyolytic ARF by single intramuscular injection of hypertonic glycerol (50% v/v; 8 ml/kg) and the animals were sacrificed after 24 hours of glycerol injection. The plasma creatinine, blood urea nitrogen, creatinine clearance, ...

  9. Microbial Conversion of Waste Glycerol from Biodiesel Production into Value-Added Products

    OpenAIRE

    Hong Liu; Cheng Li; Keaton L. Lesnik

    2013-01-01

    Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable c...

  10. Effects of modulation of glycerol kinase expression on lipid and carbohydrate metabolism in human muscle cells.

    Science.gov (United States)

    Montell, Eulàlia; Lerín, Carlos; Newgard, Christopher B; Gómez-Foix, Anna M

    2002-01-25

    Glycerol is taken up by human muscle in vivo and incorporated into lipids, but little is known about regulation of glycerol metabolism in this tissue. In this study, we have analyzed the role of glycerol kinase (GlK) in the regulation of glycerol metabolism in primary cultured human muscle cells. Isolated human muscle cells exhibited lower GlK activity than fresh muscle explants, but the activity in cultured cells was increased by exposure to insulin. [U-(14)C]Glycerol was incorporated into cellular phospholipids and triacylglycerides (TAGs), but little or no increase in TAG content or lactate release was observed in response to changes in the medium glycerol concentration. Adenovirus-mediated delivery of the Escherichia coli GlK gene (AdCMV-GlK) into muscle cells caused a 30-fold increase in GlK activity, which was associated with a marked rise in the labeling of phospholipid or TAG from [U-(14)C]glycerol compared with controls. Moreover, GlK overexpression caused [U-(14)C]glycerol to be incorporated into glycogen, which was dependent on the activation of glycogen synthase. Co-incubation of AdCMV-GlK-treated muscle cells with glycerol and oleate resulted in a large accumulation of TAG and an increase in lactate production. We conclude that GlK is the limiting step in muscle cell glycerol metabolism. Glycerol 3-phosphate is readily used for TAG synthesis but can also be diverted to form glycolytic intermediates that are in turn converted to glycogen or lactate. Given the high levels of glycerol in muscle interstitial fluid, these finding suggest that changes in GlK activity in muscle can exert important influences on fuel deposition in this tissue. PMID:11714702

  11. Quantitative analysis of glycerol accumulation, glycolysis and growth under hyper osmotic stress.

    Directory of Open Access Journals (Sweden)

    Elzbieta Petelenz-Kurdziel

    Full Text Available We provide an integrated dynamic view on a eukaryotic osmolyte system, linking signaling with regulation of gene expression, metabolic control and growth. Adaptation to osmotic changes enables cells to adjust cellular activity and turgor pressure to an altered environment. The yeast Saccharomyces cerevisiae adapts to hyperosmotic stress by activating the HOG signaling cascade, which controls glycerol accumulation. The Hog1 kinase stimulates transcription of genes encoding enzymes required for glycerol production (Gpd1, Gpp2 and glycerol import (Stl1 and activates a regulatory enzyme in glycolysis (Pfk26/27. In addition, glycerol outflow is prevented by closure of the Fps1 glycerol facilitator. In order to better understand the contributions to glycerol accumulation of these different mechanisms and how redox and energy metabolism as well as biomass production are maintained under such conditions we collected an extensive dataset. Over a period of 180 min after hyperosmotic shock we monitored in wild type and different mutant cells the concentrations of key metabolites and proteins relevant for osmoadaptation. The dataset was used to parameterize an ODE model that reproduces the generated data very well. A detailed computational analysis using time-dependent response coefficients showed that Pfk26/27 contributes to rerouting glycolytic flux towards lower glycolysis. The transient growth arrest following hyperosmotic shock further adds to redirecting almost all glycolytic flux from biomass towards glycerol production. Osmoadaptation is robust to loss of individual adaptation pathways because of the existence and upregulation of alternative routes of glycerol accumulation. For instance, the Stl1 glycerol importer contributes to glycerol accumulation in a mutant with diminished glycerol production capacity. In addition, our observations suggest a role for trehalose accumulation in osmoadaptation and that Hog1 probably directly contributes to the

  12. Modulation of crude glycerol fermentation byClostridium pasteurianum DSM 525 towards theproduction of butanol

    OpenAIRE

    Gallardo, R.; Alves, M. M.; Rodrigues, L. R.

    2014-01-01

    High production yields and productivities are requisites for the development of an industrial butanol production process based on biodiesel-derived crude glycerol. However, impurities present in this substrate and/or the concentration of glycerol itself can affect the microbial metabolism. In this work, the effect of crude glycerol concentration on the production of butanol and 1,3-propanediol (1,3-PDO) by Clostridium pasteurianum DSM 525 is studied. Also, the effect of acetate...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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

  15. Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions

    DEFF Research Database (Denmark)

    Nilsson, C.; Harwigsson, I.; Becker, K.;

    2010-01-01

    Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas (R), 6.7 cm effective length). In the absence of n...... at protein friendly conditions. The developed capillary-based method facilitates future electrochromatography of proteins on polymer-based microchips under physiological conditions and enables the initial optimization of separation conditions in parallel to the chip development....

  16. Dietary Tools To Modulate Glycogen Storage in Gilthead Seabream Muscle: Glycerol Supplementation

    DEFF Research Database (Denmark)

    Silva, Tomé S.; Matos, Elisabete; Cordeiro, Odete D.;

    2012-01-01

    The quality and shelf life of fish meat products depend on the skeletal muscle’s energetic state at slaughter, as meat decomposition processes can be exacerbated by energy depletion. In this study, we tested dietary glycerol as a way of replenishing muscle glycogen reserves of farmed gilthead......, and organoleptic properties (aroma and color). Proteomic analysis showed a low impact of glycerol-supplementation on muscle metabolism, with most changes probably reflecting increased stress coping capacity in glycerol-fed fish. This suggests inclusion of crude glycerol in gilthead seabream diets (particularly...

  17. Microbial synthesis of polyhydroxybutyrate from glycerol: gluconeogenesis, molecular weight and material properties of biopolyester.

    Science.gov (United States)

    Tanadchangsaeng, Nuttapol; Yu, Jian

    2012-11-01

    Glycerol is considered as an ideal feedstock for producing bioplastics via bacterial fermentation due to its ubiquity, low price, and high degree of reduction substrate. In this work, we study the yield and cause of limitation in poly(3-hydroxybutyrate) (PHB) production from glycerol. Compared to glucose-based PHB production, PHB produced by Cupriavidus necator grown on glycerol has a low productivity (0.92 g PHB/L/h) with a comparably low maximum specific growth rate of 0.11 h(-1) . We found that C. necator can synthesize glucose from glycerol and that the lithotrophical utilization of glycerol (non-fermentative substrate) or gluconeogenesis is an essential metabolic pathway for biosynthesis of cellular components. Here, we show that gluconeogenesis affects the reduction of cell mass, the productivity of biopolymer product, and the molecular chain size of intracellular PHB synthesized from glycerol by C. necator. We use NMR spectroscopy to show that the isolated PHB is capped by glycerol. We then characterized the physical properties of the isolated glycerol-based PHB with differential scanning calorimetry and tensile tests. We found that although the final molecular weight of the glycerol-based PHB is lower than those of glucose-based and commercial PHB, the thermal and mechanical properties of the biopolymers are similar. PMID:22566160

  18. Anaerobic and aerobic batch cultivations of Saccharomyces cerevisiae mutants impaired in glycerol synthesis

    DEFF Research Database (Denmark)

    Nissen, Torben Lauesgaard; Hamann, Claus Wendelboe; Kielland-Brandt, M. C.;

    2000-01-01

    Glycerol is formed as a by-product in production of ethanol and baker's yeast during fermentation of Saccharomyces cerevisiae under anaerobic and aerobic growth conditions, respectively. One physiological role of glycerol formation by yeast is to reoxidize NADH, formed in synthesis of biomass...... and secondary fermentation products, to NAD(+). The objective of this study was to evaluate whether introduction of a new pathway for reoxidation of NADH, in a yeast strain where glycerol synthesis had been impaired, would result in elimination of glycerol production and lead to increased yields of ethanol...

  19. Photocatalytic hydrogen generation using glycerol wastewater over Pt/TiO2

    Institute of Scientific and Technical Information of China (English)

    Min LI; Yuexiang LI; Shaoqin PENG; Gongxuan LU; Shuben LI

    2009-01-01

    Using glycerol as electron donor, photocataly-tic hydrogen generation over Pt/TiO2 was investigated.The results show that glycerol can not only improve the efficiency of photocatalytic hydrogen generation but can also be decomposed effectively. The factors which affect photocatalytic hydrogen generation, such as irradiation time, initial concentration of the glycerol solution, pH-value of the suspensions and the coexisting substances were studied. The final oxidation products of glycerol were H2O and CO2. Glyceraldhyde, glycoladehyde, glycolic acid and formaldehyde were identified as the intermedi-ates. A possible reaction mechanism was discussed.

  20. Engineering of the glycerol decomposition pathway and cofactor regulation in an industrial yeast improves ethanol production.

    Science.gov (United States)

    Zhang, Liang; Tang, Yan; Guo, Zhongpeng; Shi, Guiyang

    2013-10-01

    Glycerol is a major by-product of industrial ethanol production and its formation consumes up to 4 % of the sugar substrate. This study modified the glycerol decomposition pathway of an industrial strain of Saccharomyces cerevisiae to optimize the consumption of substrate and yield of ethanol. This study is the first to couple glycerol degradation with ethanol formation, to the best of our knowledge. The recombinant strain overexpressing GCY1 and DAK1, encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, in glycerol degradation pathway, exhibited a moderate increase in ethanol yield (2.9 %) and decrease in glycerol yield (24.9 %) compared to the wild type with the initial glucose concentration of 15 % under anaerobic conditions. However, when the mhpF gene, encoding acetylating NAD⁺-dependent acetaldehyde dehydrogenase from Escherichia coli, was co-expressed in the aforementioned recombinant strain, a further increase in ethanol yield by 5.5 % and decrease in glycerol yield by 48 % were observed for the resultant recombinant strain GDMS1 when acetic acid was added into the medium prior to inoculation compared to the wild type. The process outlined in this study which enhances glycerol consumption and cofactor regulation in an industrial yeast is a promising metabolic engineering strategy to increase ethanol production by reducing the formation of glycerol.

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

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Mortensen, Uffe Hasbro; Workman, Mhairi

    2013-01-01

    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....

  2. Determination of aggregation thresholds of UV absorbing anionic surfactants by frontal analysis continuous capillary electrophoresis.

    Science.gov (United States)

    Le Saux, Thomas; Varenne, Anne; Gareil, Pierre

    2004-06-01

    Aggregation of anionic surfactants was investigated by frontal analysis continuous capillary electrophoresis (FACCE), a method involving the continuous electrokinetic introduction of the surfactant sample into the separation capillary. This process results in a partial separation of the monomeric and aggregated forms without perturbing the monomer-aggregate equilibrium. The critical micelle concentration (CMC) can then be easily derived from the height of the firstly detected migration front, corresponding to the monomeric form. This approach is exemplified with octyl and dodecylbenzenesulfonates and compared with conductimetry and surface tension measurements. FACCE turns out to be an effective method for the determination of CMC and intermediate aggregation phenomena with very small sample and short time requirements.

  3. Capillary electrochromatography using fibers as stationary phases.

    Science.gov (United States)

    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.

  4. Capillary detectors for high resolution tracking

    CERN Document Server

    Annis, P

    1997-01-01

    We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

  5. Capillary electrochromatography using fibers as stationary phases.

    Science.gov (United States)

    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

  6. Capillary Optics generate stronger X-rays

    Science.gov (United States)

    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.

  7. Pre-exercise glycerol hydration improves cycling endurance time

    Science.gov (United States)

    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.

  8. Selectivity and detection in capillary electrophoresis

    OpenAIRE

    Khaled, Maha Yehia

    1994-01-01

    This work is a contribution to the minimization of some of the selectivity and detection limitations in capillary electrophoresis. A more practical design of an electrochemical detector is introduced with simultaneous on-line UV detection (1), for the selective detection of a number of pungent and neurological compounds, the piperines and the capsacinoids. Commercially available microelectrodes together with large 25 μm id fused silica capillary columns are used for the fir...

  9. Cell adhesion during bullet motion in capillaries.

    Science.gov (United States)

    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.

  10. Fluid trapping during capillary displacement in fractures

    Science.gov (United States)

    Yang, Zhibing; Neuweiler, Insa; Méheust, Yves; Fagerlund, Fritjof; Niemi, Auli

    2016-09-01

    The spatial distribution of fluid phases and the geometry of fluid-fluid interfaces resulting from immiscible displacement in fractures cast decisive influence on a range of macroscopic flow parameters. Most importantly, these are the relative permeabilities of the fluids as well as the macroscopic irreducible saturations. They also influence parameters for component (solute) transport, as it usually occurs through one of the fluid phase only. Here, we present a numerical investigation on the critical role of aperture variation and spatial correlation on fluid trapping and the morphology of fluid phase distributions in a geological fracture. We consider drainage in the capillary dominated regime. The correlation scale, that is, the scale over which the two facing fracture walls are matched, varies among the investigated geometries between L/256 and L (self-affine fields), L being the domain/fracture length. The aperture variability is quantified by the coefficient of variation (δ), ranging among the various geometries from 0.05 to 0.25. We use an invasion percolation based model which has been shown to properly reproduce displacement patterns observed in previous experiments. We present a quantitative analysis of the size distribution of trapped fluid clusters. We show that when the in-plane curvature is considered, the amount of trapped fluid mass first increases with increasing correlation scale Lc and then decreases as Lc further increases from some intermediate scale towards the domain length scale L. The in-plane curvature contributes to smoothening the invasion front and to dampening the entrapment of fluid clusters of a certain size range that depends on the combination of random aperture standard deviation and spatial correlation.

  11. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    Science.gov (United States)

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results. PMID:26402948

  12. Distributions of glycerol dialkyl glycerol tetraethers in surface soils of Qinghai–Tibetan Plateau: implications of GDGT-based proxies in cold and dry regions

    Directory of Open Access Journals (Sweden)

    S. Ding

    2015-01-01

    Full Text Available 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.

  13. Distributions of glycerol dialkyl glycerol tetraethers in surface soils of Qinghai-Tibetan Plateau: implications of GDGT-based proxies in cold and dry regions

    Science.gov (United States)

    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.

  14. Use of molecular dynamics to assess the biophysiological role of hydroxyl groups in glycerol dyalkyl glycerol teraethers

    Science.gov (United States)

    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.

  15. Nucleation theory - Is replacement free energy needed?. [error analysis of capillary approximation

    Science.gov (United States)

    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.

  16. Percolation study for the capillary ascent of a liquid through a granular soil

    CERN Document Server

    Cárdenas-Barrantes, M A; Araujo, N A M

    2016-01-01

    Capillary rise plays a crucial role in the construction of road embankments in flood zones, where hydrophobic compounds are added to the soil to suppress the rising of water and avoid possible damage of the pavement. Water rises through liquid bridges, menisci and trimers, whose width and connectivity depends on the maximal half-length {\\lambda} of the capillary bridges among grains. Low {\\lambda} generate a disconnect structure, with small clusters everywhere. On the contrary, for high {\\lambda}, create a percolating cluster of trimers and enclosed volumes that form a natural path for capillary rise. Hereby, we study the percolation transition of this geometric structure as a function of {\\lambda} on a granular media of monodisperse spheres in a random close packing. We determine both the percolating threshold {\\lambda}_{c} = (0.049 \\pm 0.004)R (with R the radius of the granular spheres), and the critical exponent of the correlation length {\

  17. Test results of reliable and very high capillary multi-evaporators / condenser loop

    Energy Technology Data Exchange (ETDEWEB)

    Van Oost, S.; Dubois, M.; Bekaert, G. [Societe Anonyme Belge de Construction Aeronautique - SABCA (Belgium)

    1996-12-31

    The paper present the results of various SABCA activities in the field of two-phase heat transport system. These results have been based on a critical review and analysis of the existing two-phase loop and of the future loop needs in space applications. The research and the development of a high capillary wick (capillary pressure up to 38 000 Pa) are described. These activities have led towards the development of a reliable high performance capillary loop concept (HPCPL), which is discussed in details. Several loop configurations mono/multi-evaporators have been ground tested. The presented results of various tests clearly show the viability of this concept for future applications. Proposed flight demonstrations as well as potential applications conclude this paper. (authors) 7 refs.

  18. CriticalEd

    DEFF Research Database (Denmark)

    Kjellberg, Caspar Mølholt; Meredith, David

    2014-01-01

    such as Sibelius or Finale. It was hypothesized that it would be possible to develop a Sibelius plug-in, written in Manuscript 6, that would improve the critical editing work flow, but it was found that the capabilities of this scripting language were insufficient. Instead, a 3-part system was designed and built......, consisting of a Sibelius plug-in, a cross-platform application, called CriticalEd, and a REST-based solution, which handles data storage/retrieval. A prototype has been tested at the Danish Centre for Music Publication, and the results suggest that the system could greatly improve the efficiency...

  19. Stability conditions and mechanism of cream soaps: role of glycerol.

    Science.gov (United States)

    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.

  20. Protease activation in glycerol-based deep eutectic solvents

    Science.gov (United States)

    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

  1. Theoretical studies on the unimolecular decomposition of propanediols and glycerol.

    Science.gov (United States)

    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

  2. Sustaining Biodiesel Production via Value-Added Applications of Glycerol

    Directory of Open Access Journals (Sweden)

    Omotola Babajide

    2013-01-01

    Full Text Available The production of biofuels worldwide has been significant lately due to the shift from obtaining energy from nonrenewable energy (fossil fuels to renewable sources (biofuels. This energy shift arose as a result of the disturbing crude petroleum price fluctuations, uncertainties about fossil fuel reserves, and greenhouse gas (GHG concerns. With the production of biofuels increasing considerably and the current global biodiesel production from different feedstock, reaching about 6 billion liters per year, biodiesel production costs have been highly dependent on feedstock prices, ranging from 70 to 25; of total production costs, and in comparison with the conventional diesel fuel, the biodiesel is currently noncompetitive. An efficient production process is, therefore, crucial to lowering biodiesel production costs. The question of sustainability, however, arises, taking into account the African diverse conditions and how vital concerns need to be addressed. The major concern about biodiesel production costs can be reduced by finding value-added applications for its glycerol byproduct. This paper, thus, provides an overview of current research trends that could overcome the major hurdles towards profitable commercialization of biodiesel and also proposes areas of opportunity probable to capitalize the surplus glycerol obtained, for numerous applications.

  3. Crossover from shear-driven to thermally activated drainage of liquid-infused microscale capillaries

    Science.gov (United States)

    Colosqui, Carlos E.; Wexler, Jason S.; Liu, Ying; Stone, Howard A.

    2016-10-01

    The shear-driven drainage of capillary grooves filled with viscous liquid is a dynamic wetting phenomenon relevant to numerous industrial processes and lubricant-infused surfaces for drag reduction and antifouling. Prior work has reported that a finite length L∞ of the capillary groove can remain indefinitely filled with liquid even when large shear stresses are applied. The mechanism preventing full drainage is attributed to a balance between the shear-driven flow and a counterflow driven by capillary pressures caused by deformation of the free surface. In this work, we examine closely the approach to the final equilibrium length L∞ and report a crossover to a slow drainage regime that cannot be described by conventional dynamic models considering solely hydrodynamic and capillary forces. The slow drainage regime observed in experiments can be instead modeled by a kinetic equation describing a sequence of random thermally activated transitions between multiple metastable states caused by surface defects with nanoscale dimensions. Our findings provide insights on the critical role that natural or engineered surface roughness with nanoscale dimensions can play in the imbibition and drainage of capillaries and other dynamic wetting processes in microscale systems.

  4. A Novel Polybrene/Chondroitin Sulfate C Double Coated Capillary and Its Application in Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    DU,Ying-Xiang(杜迎翔); HONDA,Susumu; TAGA,Atsushi; LIU,Wen-Ying(刘文英); SUZUKI,Shigeo

    2002-01-01

    A new capillary coated by double polymer, polybrene/chondroitin sulfate C (P/CC), was developed using a simple procedure. The P/CC double coated capillary showed long lifetime,strong chemical stability and good reproducibility. It endured during more than 100 replicated analyses and was also tolerant to HCl (1 mol/L), NaOH (0.01 mol/L), CH3OH and CH3CN. The P/CC double coated capillary can be applied to basic drug analyses. The adsorption of basic drugs to the capillary wall was suppressed and the peak tailing greatly decreased. The use of the P/CC double coated capillary allowed excelent separation of the enantiomers of some basic drugs by using chondroitin sulfate C as the chiral selector, ami the peak symmetry of basic drugs was further improved under these conditions.

  5. Seasonal changes in glycerol dialkyl glycerol tetraether concentrations and fluxes in a perialpine lake: Implications for the use of the TEX86 and BIT proxies

    OpenAIRE

    Blaga, C. I.; G. J. Reichart; Vissers, E.W.; Lotter, A. F.; Anselmetti, F. S.; Sinninghe Damsté, J.S.

    2011-01-01

    To determine where and when glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in lakes are produced, we collected descending particles in Lake Lucerne (Switzerland) using two sediment traps (at 42 and 72 m water depth) with a monthly resolution from January 2008 to late March 2009. Suspended particulate matter (SPM) was monthly filtered from the water column at three different depths. The potential application of GDGTs in palaeoenvironmental and palaeoclimatic reconstructions was in...

  6. Distributions of glycerol dialkyl glycerol tetraethers in surface soils of Qinghai–Tibetan Plateau: implications of GDGT-based proxies in cold and dry regions

    OpenAIRE

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

    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 a...

  7. Influence of lake water pH and alkalinity on the distribution of coreand intact polar branched glycerol dialkyl glycerol tetraethers (GDGTs) in lakes

    OpenAIRE

    Schoon, P. L.; de Kluijver, A.; Middelburg, J.J.; J. A. Downing; Sinninghe Damsté, J. S.; Schouten, S.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) are bacterial membrane lipids, ubiquitously present in soils and peat bogs, as well as in rivers, lakes and lake sediments. Their distribution in soil is controlled mainly by pH and mean annual air temperature, but the controls on their distribution in lake sediments are less well understood. Several studies have found a relationship between the distribution of branched GDGTs in lake sediments and average lake water pH, suggesting an aqua...

  8. Chemoselective Oxidation of Bio-Glycerol with Nano-Sized Metal Catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Kotni, Ramakrishna; Zhang, Qiuyun;

    2015-01-01

    selectively oxidize glycerol and yield products with good selectivity is the use of nano-sized metal particles as heterogeneous catalysts. In this short review, recent developments in chemoselective oxidation of glycerol to specific products over nano-sized metal catalysts are described. Attention is drawn to...

  9. Separation of oily sludge and glycerol from biodiesel processing waste by coagulation

    Directory of Open Access Journals (Sweden)

    Qiao-guang Xie1,

    2011-12-01

    Full Text Available Raw waste glycerol is a by-product of biodiesel production from transesterification, which is high in salt, and has a highpH value (more than 9.6. The purpose of this research is to reduce the water pollution from waste glycerol by using acoagulation process and discussing the possibility of waste glycerol reuse. The commercial coagulant (2% by weight, whichwas composed by cationic polyamine (PA 6% and poly-aluminium chloride (PACl 94% (w/w, was used as coagulant totreat waste glycerol. The results showed that after acidification and coagulation process, most of the chemical oxygen demand(COD, biochemical oxygen demand (BOD5, total suspended solids (TSS, and oily sludge (such as fatty acid, methyl ester,methanol and soap in raw waste glycerol were removed, except glycerol. The removal efficiencies of COD, BOD5, TSS, soapand methanol were 96.2%, 93.3%, 98.1%, 100%, and 85.8%, respectively, but the removal efficiency of glycerol was only65.4%. There was still a certain amount of glycerol (about 147.5g/L in the solution, which is separated from oily sludge.

  10. Bench scale demonstration of the Supermethanol concept : The synthesis of methanol from glycerol derived syngas

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2012-01-01

    An integrated process for the synthesis of methanol from aqueous glycerol involving reforming of the feed to syngas followed by methanol synthesis is successfully demonstrated in a continuous bench scale unit. Glycerol reforming was carried out at pressures of 24-27 MPa and temperatures of 948-998 K

  11. Sequential spectrofluorimetric determination of free and total glycerol in biodiesel in a multicommuted flow system

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sidnei G. [Universidade de Sao Paulo, Instituto de Quimica, Sao Paulo (Brazil); Morales-Rubio, Angel; Guardia, Miguel de la [Universidad de Valencia, Department of Analytical Chemistry, Burjassot, Valencia (Spain); Rocha, Fabio R.P. [Universidade de Sao Paulo, Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

    2011-07-15

    A new procedure for spectrofluorimetric determination of free and total glycerol in biodiesel samples is presented. It is based on the oxidation of glycerol by periodate, forming formaldehyde, which reacts with acetylacetone, producing the luminescent 3,5-diacetyl-1,4-dihydrolutidine. A flow system with solenoid micro-pumps is proposed for solution handling. Free glycerol was extracted off-line from biodiesel samples with water, and total glycerol was converted to free glycerol by saponification with sodium ethylate under sonication. For free glycerol, a linear response was observed from 5 to 70 mg L{sup -1} with a detection limit of 0.5 mg L{sup -1}, which corresponds to 2 mg kg{sup -1} in biodiesel. The coefficient of variation was 0.9% (20 mg L{sup -1}, n = 10). For total glycerol, samples were diluted on-line, and the linear response range was 25 to 300 mg L{sup -1}. The detection limit was 1.4 mg L{sup -1} (2.8 mg kg{sup -1} in biodiesel) with a coefficient of variation of 1.4% (200 mg L{sup -1}, n = 10). The sampling rate was ca. 35 samples h{sup -1} and the procedure was applied to determination of free and total glycerol in biodiesel samples from soybean, cottonseed, and castor beans. (orig.)

  12. Synthesis of biodiesel fuel additives from glycerol using green chemistry and supercritical fluids

    Science.gov (United States)

    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...

  13. Effect of glycerol on the morphology of starch-sunflower oil composites

    NARCIS (Netherlands)

    Yilmaz, G.; Jongboom, R.O.J.; Soest, van J.J.G.; Feil, H.

    1999-01-01

    The presented study involves the encapsulation of sunflower oil in starch by casting emulsions of oil in aqueous starch solutions. Glycerol was used as a plasticizer and lecithin was used as an emulsifier, to improve the emulsion stability. Increasing glycerol concentration in the samples resulted i

  14. Co-digestion of sewage sludge with glycerol to boost biogas production

    International Nuclear Information System (INIS)

    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 oC. 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 CH4/d before the addition of glycerol and 2353 ± 94 ml CH4/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 (μmax) and the saturation constant (KS) 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.

  15. Deer Frozen Semen Quality in Tris Sucrose and Tris Glucose Extender with Different Glycerol Concentrations

    Directory of Open Access Journals (Sweden)

    W. M. M. Nalley

    2011-01-01

    Full Text Available In order to improve Timor deer (Cervus timorensis frozen semen quality, the influence of sugar and glycerol concentration on semen characteristics of sperm was investigated. The semen was collected from five sexually mature Timor deer using an electroejaculator. The semen was evaluated and divided into six equal tubes and diluted with Tris sucrose glycerol 10% (TSG10; Tris sucrose glycerol 12% (TSG12; Tris sucrose glycerol 14% (TSG14; Tris glucose glycerol 10% (TGG10; Tris glucose glycerol 12% (TGG12; and Tris glucose glycerol 14% (TGG14. The diluted semen was packed in 0.3 ml minitub straw, equilibrated at 5 oC for 4 hours and frozen on liquid nitrogen vapor for 10 minutes. The total of forward motility, viability, acrosome integrity and membrane integrity were assessed in fresh, after equilibration and after thawing. Results demonstrated that the percentage of sperm motility in TSG10 was higher (P<0.05 than those diluted in other extenders. The highest viability of sperm was demonstrated in TSG10 (63.93±7.23%. The sperm in TSG10 and TSG14 extender were superior in acrosome as well as in membrane integrity. It was concluded that Tris Sucrose with 10% glycerol protected Timor deer sperm better than other combinations.

  16. Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2011-05-01

    Full Text Available An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR spectra, thermogravimetry (TGA and differential scanning calorimetry (DSC curves. Scanning Electron Microscopy (SEM observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering.

  17. REGIOSPECIFIC ANALYSIS OF DIRICINOLEOYL-ACYL-GLYCEROL IN CASTOR OIL USING ELECTROSPRAY IONIZATION-MASS SPECTROMETRY

    Science.gov (United States)

    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...

  18. Model studies on acrylamide generation from glucose/asparagine in aqueous glycerol

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Frandsen, Henrik Lauritz; Granby, Kit;

    2007-01-01

    Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33......Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33...

  19. Inhibitory Effect Evaluation of Glycerol-Iron Oxide Thin Films on Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    C. L. Popa

    2015-01-01

    Full Text Available The main purpose of this study was to evaluate the inhibitory effect of glycerol- iron oxide thin films on Methicillin-Resistant Staphylococcus aureus (MRSA. Our results suggest that glycerol-iron oxide thin films could be used in the future for various biomedical and pharmaceutical applications. The glycerol-iron oxide thin films have been deposited by spin coating method on a silicon (111 substrate. The structural properties have been studied by X-ray diffraction (XRD and scanning electron spectroscopy (SEM. The XRD investigations of the prepared thin films demonstrate that the crystal structure of glycerol-iron oxide nanoparticles was not changed after spin coating deposition. On the other hand, the SEM micrographs suggest that the size of the glycerol-iron oxide microspheres increased with the increase of glycerol exhibiting narrow size distributions. The qualitative depth profile of glycerol-iron oxide thin films was identified by glow discharge optical emission spectroscopy (GDOES. The GDOES spectra revealed the presence of the main elements: Fe, O, C, H, and Si. The antimicrobial activity of glycerol-iron oxide thin films was evaluated by measuring the zone of inhibition. After 18 hours of incubation at 37°C, the diameters of the zones of complete inhibition have been measured obtaining values around 25 mm.

  20. Biodegradable Composites Based on Starch/EVOH/Glycerol Blends and Coconut Fibers

    Science.gov (United States)

    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 ...

  1. Rational design of glycerol dehydratase: Swapping the genes encoding the subunits of glycerol dehydratase to improve enzymatic properties

    Institute of Scientific and Technical Information of China (English)

    QI Xianghui; SUN Liang; LUO Zhaofei; WU Jiequn; MENG Xiaolei; TANG Yue; WEI Yutuo; HUANG Ribo

    2006-01-01

    1,3-propanediol (1,3-PD) is an important material for chemical industry, and there has been always much interest in the production of 1,3-PD using all possible routes. The genes encoding glycerol dehydratase (GDHt) from Citrobacter freundii,Klebsiella pneumoniae and metagenome were cloned and expressed in E. coli. All glycerol dehydratases but the one from metagenome could be detected to show enzyme activities. In order to improve the enzymatic properties of GDHts, the genes encoding α and β-γ subunits were cloned, and the enzyme characteristics were evolved by rational design based on their 3D structures which were constructed by homology modeling. Six heteroenzymes were obtained by swapping the α subunit genes of these three different-source-derived GDHts. The pH,thermal stability and Vmax of some heteroenzymes were dramatically improved by 2-5 times compared with the wild one (GDHtKP). The GDHt cloned from metagenome, originally proved to be with no enzyme activity, was converted into active enzyme by swapping its subunits with other different GDHts. In addition, the effect of subtle 3D structural changes on the properties of the enzyme was also observed.

  2. Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa

    Science.gov (United States)

    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.

  3. Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol.

    Science.gov (United States)

    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

  4. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jun Hu

    Full Text Available 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

  5. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    Science.gov (United States)

    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

  6. Using glycerol produced from biodiesel as a plasticiser in extruded biodegradable films

    Directory of Open Access Journals (Sweden)

    Ana Paula Bilck

    2015-08-01

    Full Text Available AbstractThe demand for renewably sourced biodegradable materials has increased the need to produce materials that combine appropriate functional properties at competitive costs. Thermoplastic starch and polyester blends are an interesting alternative to current materials due to the low cost of starch and the functional properties and processability of the resulting blends. Producing thermoplastic starch (TPS requires using a plasticiser at concentrations between 20 and 30%wt (in relation to starch. Glycerol is the most common plasticiser due to its high plasticising capacity and thermal stability at processing temperatures. The objective of this study was to evaluate glycerol waste from the biodiesel industry, with different degrees of purification, as plasticisers for TPS / poly (butylene adipate-co-terephthalate (PBAT blends. Different purities of glycerol produced films with similar mechanical, optical and barrier properties to those made with purified glycerol (99.7%. Therefore, crude glycerol is a renewable alternative plasticiser that reduces the cost of plasticisation by 6-fold.

  7. Modeling, Simulation and Optimization of Hydrogen Production Process from Glycerol using Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeongpil; Cho, Sunghyun; Kim, Tae-Ok; Shin, Dongil [Myongji University, Yongin (Korea, Republic of); Lee, Seunghwan [JNK Heaters, Seoul (Korea, Republic of); Moon, Dong Ju [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2014-12-15

    For improved sustainability of the biorefinery industry, biorefinery-byproduct glycerol is being investigated as an alternate source for hydrogen production. This research designs and optimizes a hydrogen-production process for small hydrogen stations using steam reforming of purified glycerol as the main reaction, replacing existing processes relying on steam methane reforming. Modeling, simulation and optimization using a commercial process simulator are performed for the proposed hydrogen production process from glycerol. The mixture of glycerol and steam are used for making syngas in the reforming process. Then hydrogen are produced from carbon monoxide and steam through the water-gas shift reaction. Finally, hydrogen is separated from carbon dioxide using PSA. This study shows higher yield than former U.S.. DOE and Linde studies. Economic evaluations are performed for optimal planning of constructing domestic hydrogen energy infrastructure based on the proposed glycerol-based hydrogen station.

  8. Enzymatic production of glycerol carbonate from by-product after biodiesel manufacturing process.

    Science.gov (United States)

    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

  9. Performance of a direct glycerol fuel cell using KOH doped polybenzimidazole as electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Ana P.; Linares, Jose J., E-mail: joselinares@unb.br [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Instituto de Quimica

    2014-03-15

    This paper studies the influence of the operating variables (glycerol concentration, temperature and feed rate) for a direct glycerol fuel cell fed with glycerol using polybenzimidazole (PBI) impregnated with KOH as electrolyte and Pt/C as catalyst. Temperature displays a beneficial effect up to 75 °C due to the enhanced conductivity and kinetics of the electrochemical reactions. The optimum cell feed corresponds to 1 mol L{sup -1} glycerol and 4 mol L{sup -1} KOH, supplying sufficient quantities of fuel and electrolyte without massive crossover nor mass transfer limitations. The feed rate increases the performance up to a limit of 2 mL min{sup -1}, high enough to guarantee the access of the glycerol and the exit of the products. Finally, the use of binary catalysts (PtRu/C and Pt{sub 3}Sn/C) is beneficial for increasing the cell performance. (author)

  10. Synthetic Capillaries to Control Microscopic Blood Flow

    Science.gov (United States)

    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.

  11. EUV radiation from nitrogen capillary discharge

    Science.gov (United States)

    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.

  12. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise.

    Science.gov (United States)

    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

  13. Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography–mass spectrometry

    OpenAIRE

    JUN WANG; DINGQIANG LU; XIUQUAN LING; SHUMIN ZHANG; MINGXIN LIANG; PINGKAI OUYANG; JIANHUI CHEN; WEI REN

    2010-01-01

    As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on...

  14. Capillary Phase-Transition and Self-Diffusion of Ethylene in the Slit Carbon Pores%乙烯分子在狭缝炭孔内的毛细相变和自扩散

    Institute of Scientific and Technical Information of China (English)

    刘涛; 刘洪来; 袁渭康

    2004-01-01

    The grand canonical Monte Carlo (GCMC), the canonical Monte Carlo by using equal probability perturbation, and the molecular dynamics (MD) methods were used to study the capillary phase-transition (capillary condensation and evaporation) and self-diffusion for a simple Lennard-Jones model of ethylene confined in slit carbon pores of 2.109 nm at temperatures between 141.26 K and 201.80 K. The critical point of capillary phase-transition was extrapolated by the critical power law and the law of rectilinear diameter from the capillary phase-transition data in the near critical region. The effects of temperature and fluid density on the parallel self-diffusion coefficients of ethylene molecules confined in the slit carbon pores were examined. The results showed that the parallel selfdiffusion coefficients in the capillary phase transition area strongly depended on the fluids local densities in the slit carbon pores.

  15. Capillary rise of water in hydrophilic nanopores

    CERN Document Server

    Gruener, Simon; Wallacher, Dirk; Kityk, Andriy V; Huber, Patrick; 10.1103/PhysRevE.79.067301

    2009-01-01

    We report on the capillary rise of water in three-dimensional networks of hydrophilic silica pores with 3.5nm and 5nm mean radii, respectively (porous Vycor monoliths). We find classical square root of time Lucas-Washburn laws for the imbibition dynamics over the entire capillary rise times of up to 16h investigated. Provided we assume two preadsorbed strongly bound layers of water molecules resting at the silica walls, which corresponds to a negative velocity slip length of -0.5nm for water flow in silica nanopores, we can describe the filling process by a retained fluidity and capillarity of water in the pore center. This anticipated partitioning in two dynamic components reflects the structural-thermodynamic partitioning in strongly silica bound water layers and capillary condensed water in the pore center which is documented by sorption isotherm measurements.

  16. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Pagliardini, Julien; Hubmann, Georg; Alfenore, Sandrine; Nevoigt, Elke; Bideaux, Carine; Guillouet, Stephane E.

    2013-01-01

    Background: Finely regulating the carbon flux through the glycerol pathway by regulating the expression of the rate controlling enzyme, glycerol-3-phosphate dehydrogenase (GPDH), has been a promising approach to redirect carbon from glycerol to ethanol and thereby increasing the ethanol yield in eth

  18. Quantitative evaluation of yeast's requirement for glycerol formation in very high ethanol performance fed-batch process

    NARCIS (Netherlands)

    Pagliardini, Julien; Hubmann, Georg; Bideaux, Carine; Alfenore, Sandrine; Nevoigt, Elke; Guillouet, Stéphane E.

    2010-01-01

    Background: Glycerol is the major by-product accounting for up to 5% of the carbon in Saccharomyces cerevisiae ethanolic fermentation. Decreasing glycerol formation may redirect part of the carbon toward ethanol production. However, abolishment of glycerol formation strongly affects yeast's robustne

  19. High-current carbon-epoxy capillary cathode

    Science.gov (United States)

    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.

  20. Directional transport of impinging capillary jet on wettability engineered surfaces

    Science.gov (United States)

    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).

  1. Molecular dynamics simulations of glycerol glass-forming liquid

    Energy Technology Data Exchange (ETDEWEB)

    Blieck, J. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires, CNRS UMR 8024, BAT P5-Cite Scientifique, Universite Lille I, 59655 Villeneuve d' Ascq Cedex (France); Affouard, F. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires, CNRS UMR 8024, BAT P5-Cite Scientifique, Universite Lille I, 59655 Villeneuve d' Ascq Cedex (France)], E-mail: frederic.affouard@univ-lille1.fr; Bordat, P. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires, CNRS UMR 8024, BAT P5-Cite Scientifique, Universite Lille I, 59655 Villeneuve d' Ascq Cedex (France); Lerbret, A. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires, CNRS UMR 8024, BAT P5-Cite Scientifique, Universite Lille I, 59655 Villeneuve d' Ascq Cedex (France); Descamps, M. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires, CNRS UMR 8024, BAT P5-Cite Scientifique, Universite Lille I, 59655 Villeneuve d' Ascq Cedex (France)

    2005-10-31

    Structural and dynamical properties of liquid glycerol have been investigated by Molecular Dynamics simulations. An improved model based on a slight reparametrisation of the all-atoms AMBER force field used in [R. Chelli, P. Procacci, G. Cardini, R.G.D. Valle, S. Califano, Phys. Chem. Chem. Phys. 1 (1999) 871] is presented. The structure remains satisfactory, qualitatively similar to that obtained from the original model. This new model is also found to reproduce significantly better the diffusion coefficient and the correlations times as they can be deduced from neutron spin echo (NSE) experiments. Structural heterogeneities revealed as a pre-peak of the static structure factor S(Q) close to Q {approx} 0.6 A{sup -1} are observed. Our results are also found compatible with predictions of the Mode Coupling Theory.

  2. Facile preparation of SiO2/TiO2 composite monolithic capillary column and its application in enrichment of phosphopeptides.

    Science.gov (United States)

    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

  3. Mach-like capillary-gravity wakes.

    Science.gov (United States)

    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.

  4. Capillary Rise of Liquids in Nanopores

    CERN Document Server

    Huber, Patrick; Kityk, Andriy V

    2006-01-01

    We present measurements on the spontaneous imbibition (capillary rise) of water, a linear hydrocarbon (n-C16H34) and a liquid crystal (8OCB) into the pore space of monolithic, nanoporous Vycor glass (mean pore radius 5 nm). Measurements on the mass uptake of the porous hosts as a function of time, m(t), are in good agreement with the Lucas-Washburn square root of time prediction, typical of imbibition of liquids into porous hosts. The relative capillary rise velocities scale as expected from the bulk fluid parameters.

  5. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng

    2015-01-01

    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows

  6. A lymph nodal capillary-cavernous hemangioma.

    Science.gov (United States)

    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

  7. Intracerebral Capillary Hemangioma: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Youn, In Young; Kim, Jae Kyun; Byun, Jun Soo [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of); Park, Eon Sub [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of)

    2012-01-15

    Intracerebral capillary hemangiomas are very rare benign vascular tumors that mostly occur during infancy. We described a 69-year-old man with generalized tonic-clonic seizures who was diagnosed with an intracranial mass. Multidetector computed tomography, magnetic resonance imaging and digital subtraction angiography studies were performed for evaluation of brain, and there was a well-enhancing mass found in the right temporal lobe without a definite feeding vessel. The patient underwent surgery and the pathologic examination demonstrated marked proliferation of small vessels with a lobular pattern in the brain parenchyma, which was confirmed to be capillary hemangioma.

  8. Viscosity measurement in the capillary tube viscometer under unsteady flow

    International Nuclear Information System (INIS)

    The objective of the present study is to develop a new device that the viscous characteristics of fluids are determined by applying the unsteady flow concept to the traditional capillary tube viscometer. The capillary tube viscometer consists of a small cylindrical reservoir, capillary tube, a load cell system that measures the mass flow rate, interfaces, and computer. Due to the small size of the reservoir the height of liquid in the reservoir decreases as soon as the liquid in the reservoir drains out through the capillary and the mass flow rate in the capillary decreases as the hydrostatic pressure in the reservoir decreases resulting in a decrease of the shear rate in the capillary tube. The instantaneous shear rate and driving force in the capillary tube are determined by measuring the mass flow rate through the capillary, and the fluid viscosity is determined from the measured flow rate and the driving force

  9. A Rare Association of Trigeminal Autonomic Cephalgia: Pontine Capillary Telangiectasia

    OpenAIRE

    Gocmen, Rahsan; Kurt, Erdal; Arslan, Sabina; Unal-Cevik, Isin; Karli Oguz, Kader; Tezer, F Irsel

    2015-01-01

    This report describes a case of pontine capillary telangiectasia in a 43-year-old woman with a clinical diagnosis of trigeminal autonomic cephalgia. The possible association with pontine capillary telangiectasia and trigeminal autonomic cephalgia is discussed.

  10. Metabolism of glycerol, glucose, and lactate in the citric acid cycle prior to incorporation into hepatic acylglycerols.

    Science.gov (United States)

    Jin, Eunsook S; Sherry, A Dean; Malloy, Craig R

    2013-05-17

    During hepatic lipogenesis, the glycerol backbone of acylglycerols originates from one of three sources: glucose, glycerol, or substrates passing through the citric acid cycle via glyceroneogenesis. The relative contribution of each substrate source to glycerol in rat liver acylglycerols was determined using (13)C-enriched substrates and NMR. Animals received a fixed mixture of glucose, glycerol, and lactate; one group received [U-(13)C6]glucose, another received [U-(13)C3]glycerol, and the third received [U-(13)C3]lactate. After 3 h, the livers were harvested to extract fats, and the glycerol moiety from hydrolyzed acylglycerols was analyzed by (13)C NMR. In either fed or fasted animals, glucose and glycerol provided the majority of the glycerol backbone carbons, whereas the contribution of lactate was small. In fed animals, glucose contributed >50% of the total newly synthesized glycerol backbone, and 35% of this contribution occurred after glucose had passed through the citric acid cycle. By comparison, the glycerol contribution was ~40%, and of this, 17% of the exogenous glycerol passed first through the cycle. In fasted animals, exogenous glycerol became the major contributor to acylglycerols. The contribution from exogenous lactate did increase in fasted animals, but its overall contribution remained small. The contributions of glucose and glycerol that had passed through the citric acid cycle first increased in fasted animals from 35 to 71% for glucose and from 17 to 24% for glycerol. Thus, a substantial fraction from both substrate sources passed through the cycle prior to incorporation into the glycerol moiety of acylglycerols in the liver.

  11. Meta-analysis: Effects of glycerol administration on plasma volume, haemoglobin, and haematocrit.

    Science.gov (United States)

    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

  12. Metabolic engineering of the ethanol fermentation by Saccharomyces cerevisiae away from glycerol formation towards alternative products

    Energy Technology Data Exchange (ETDEWEB)

    Kumar Jain, V.; Divol, B.; Prior, B.; Franz Bauer, F. [Stellenbosch Univ., (South Africa). Inst. for Wine Biotechnology

    2009-07-01

    This study investigated the commercial advantage of eliminating glycerol from the ethanol fermentation process and possible replacement with other value products. Under fermentative conditions yeast re-oxidizes excess NADH through glycerol production which involves NADH-dependent glycerol-3-phosphate dehydrogenase. Deletion of these two genes renders the cells incapable of maintaining fermentative activity under anaerobic conditions due to accumulation of NADH. This study examined the feasibility of converting this excess NADH to Nad by transforming a glycerol synthesizing double mutant with genes that could restore the redox balance in the yeast. The study showed that although glycerol formation can be eliminated during fermentation, no alternative redox balancing pathway is as efficient at the glycerol pathway in maintaining fermentation. Alternative products such as sorbitol and 1,2propanediol can be produced instead of glycerol, but these genetic manipulations were shown to have negative effects on fermentative ability. Ethanol yields, but not concentrations, were improved in mutants. Significant amounts of acetate were also produced. This paper discussed the metabolic and biotechnological implications of these findings. tabs., figs.

  13. Production of fumaric acid from biodiesel-derived crude glycerol by Rhizopus arrhizus.

    Science.gov (United States)

    Zhou, Yuqing; Nie, Kaili; Zhang, Xin; Liu, Shihong; Wang, Meng; Deng, Li; Wang, Fang; Tan, Tianwei

    2014-07-01

    This work investigated the capability of Rhizopus arrhizus to assimilate biodiesel-derived crude glycerol and convert it into fumaric acid. After optimizing the initial glycerol concentration, spore inoculum and yeast extract concentration, smaller pellets (0.7 mm) and higher biomass (3.11 g/L) were obtained when R. arrhizus grew on crude glycerol. It was found that crude glycerol was more suitable than glucose for smaller R. arrhizus pellet forming. When 80 g/L crude glycerol was used as carbon source, the fumaric acid production of 4.37 g/L was obtained at 192 h. With a highest concentration of 22.81 g/L achieved in the co-fermentation of crude glycerol (40 g/L) and glucose (40 g/L) at 144 h, the fumaric acid production was enhanced by 553.6%, compared to the fermentation using glycerol (80 g/L) as sole carbon source. Moreover, the production cost of fumaric acid in co-fermentation was reduced by approximately 14% compared to glucose fermentation. PMID:24787316

  14. PURIFICATION OF CRUDE GLYCEROL FROM INDUSTRIAL WASTE: EXPERIMENTAL AND SIMULATION STUDIES

    Directory of Open Access Journals (Sweden)

    WAN NOR ROSLAM WAN ISAHAK

    2016-08-01

    Full Text Available In this study, the purification of crude glycerol as a by-product of transesterification reaction was investigated. The first purification stage of the crude glycerol was achieved by employing the neutralization method, followed by microfiltration using 0.45µm filter membrane. Only glycerol peak could be detected by high performance liquid chromatography analysis which indicating that the neutralization step enabled to removal of excess homogeneous catalyst as well as the unreacted free fatty acids from crude glycerol samples. However, the free ions from salt and catalyst were then eliminated through an ion exchange process using two types of Amberlite resins to produce higher glycerol purity up to 99.4%. The purity of glycerol was confirmed by the other analysis such as the Fourier transform infrared, United States Pharmacopoeia and American society for testing and materials methods. The simulation studies were applied using Super-Pro-Designer 7.0 software which can provide the data for scale up to industrial scale. The P2 and P5 simulation process gives a higher purity of pure glycerol of 98.35 wt.% and 99.27 wt%, respectively were generated after through several combinatorial purification steps. The combination between the experimental and simulation process showed a good way to investigate the laboratory experiment input for possible industry scale in future.

  15. Ultrastructure and histochemistry of rat myocardial capillary endothelial cells in response to diabetes and hypertension

    Institute of Scientific and Technical Information of China (English)

    Ludmila OKRUHLICOVA; Narcis TRIBULOVA; Peter WEISMANN; Ruzena SOTNIKOVA

    2005-01-01

    Insufficient growth and rarefaction of capillaries,followed by endothelial dysfunction may represent one of the most critical mechanisms involved in heart damage.In this study we examined histochemical and ultrastructural changes in myocardial capillary endothelium in two models of heart failure streptozotocin-induced diabetes mellitus (STZ) and NOdeficient hypertension in male Wistar rats.Diabetes was induced by a single i.v.dose of STZ (45 mg/kg) and chronic 9-week stage was analysed.To induce NO-deficient hypertension,animals were treated with inhibitor of NO synthase Lnitroarginine methylester (L-NAME) (40 mg/kg) for 4 weeks.Left ventricular tissue was processed for enzyme catalytic histochemistry of capillary alkaline phosphatase (AlPh),dipeptidyl peptidase Ⅳ (DPP Ⅳ),and endothelial NO synthase/NADPH-diaphorase (NOS) and for ultrastructural analysis.In diabetic and hypertensive rats,lower/absent AlPh and DPP Ⅳ activities were found in focal micro-areas.NOS activity was significantly reduced and persisted only locally.Quantitative evaluation demonstrated reduction of reaction product intensity of AlPh,DPP and NOS by 49.50%,74.36%,20.05% in diabetic and 62.93%,82.71%,37.65% in hypertensive rats.Subcellular alterations of endothelial cells were found in heart of both groups suggesting injury of capillary function as well as compensatory processes.Endothelial injury was more significant in diabetic animals,in contrast the adaptation was more evident in hypertensive ones.Concluding: both STZ-induced diabetes- and NO-deficient hypertension-related cardiomyopathy were accompanied by similar features of structural remodelling of cardiac capillary network manifested as angiogenesis and angiopathy.The latter was however,predominant and may accelerate disappearance of capillary endothelium contributing to myocardial dysfunction.

  16. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    Science.gov (United States)

    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.

  17. Evidence of moisture control on the methylation of branched glycerol dialkyl glycerol tetraethers in semi-arid and arid soils

    Science.gov (United States)

    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 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.

  18. Influence of water availability in the distributions of branched glycerol dialkyl glycerol tetraether in soils of the Iberian Peninsula

    Science.gov (United States)

    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.

  19. High-frequency capillary waves excited by oscillating microbubbles

    CERN Document Server

    Pommella, Angelo; Poulichet, Vincent; Garbin, Valeria

    2013-01-01

    This fluid dynamics video shows high-frequency capillary waves excited by the volumetric oscillations of microbubbles near a free surface. The frequency of the capillary waves is controlled by the oscillation frequency of the microbubbles, which are driven by an ultrasound field. Radial capillary waves produced by single bubbles and interference patterns generated by the superposition of capillary waves from multiple bubbles are shown.

  20. Reaction pathways for catalytic gas-phase oxidation of glycerol over mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Suprun, W.; Glaeser, R.; Papp, H. [Leipzig Univ. (Germany). Inst. of Chemical Technology

    2011-07-01

    Glycerol as a main by-product from bio-diesel manufacture is a cheap raw material with large potential for chemical or biochemical transformations to value-added C3-chemicals. One possible way of glycerol utilization involves its catalytic oxidation to acrylic acid as an alternative to petrochemical routes. However, this catalytic conversion exhibits various problems such as harsh reaction conditions, severe catalyst coking and large amounts of undesired by-products. In this study, the reaction pathways for gas-phase conversion of glycerol over transition metal oxides (Mo, V und W) supported on TiO{sub 2} and SiO{sub 2} were investigated by two methods: (i) steady state experiments of glycerol oxidation and possible reactions intermediates, i.e., acrolein, 3-hydroxy propionaldehyde and acetaldehyde, and (ii) temperature-programmed surface reaction (TPSR) studies of glycerol conversion in the presence and in the absence of gas-phase oxygen. It is shown that the supported W-, V and Mo-oxides possess an ability to catalyze the oxidation of glycerol to acrylic acid. These investigations allowed us to gain a deeper insight into the reaction mechanism. Thus, based on the obtained results, three possible reactions pathways for the selective oxidation of glycerol to acrylic acid on the transition metal-containing catalysts are proposed. The major pathways in presence of molecular oxygen are a fast successive destructive oxidation of glycerol to CO{sub x} and the dehydration of glycerol to acrolein which is a rate-limiting step. (orig.)

  1. Application of CHESS single-bounce capillaries at synchrotron beamlines

    Science.gov (United States)

    Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.

    2014-03-01

    Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

  2. Cyclodextrin-Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications.

    Science.gov (United States)

    Adly, Frady G; Antwi, Nana Yaa; Ghanem, Ashraf

    2016-02-01

    In this review, the recently reported approaches for the preparation of cyclodextrin-functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97-109, 2016. © 2015 Wiley Periodicals, Inc.

  3. Design criteria for SW-205 capillary system

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, W.J.

    1989-04-01

    This design criteria covers the converting of the SW-250 Capillary System from fumehood manual operation to sealed glovebox automated operation. The design criteria contains general guidelines and includes drawings reflecting a similar installation at another site. Topics include purpose and physical description, architectural-engineering requirements, reference document, electrical, fire protection, occupational safety and health, quality assurance, and security.

  4. Planetary In Situ Capillary Electrophoresis System (PISCES)

    Science.gov (United States)

    Willis, P. A.; Stockton, A. M.; Mora, M. F.; Cable, M. L.; Bramall, N. E.; Jensen, E. C.; Jiao, H.; Lynch, E.; Mathies, R. A.

    2012-10-01

    We propose to develop PISCES, a 3-kg, 2W, flight-capable microfluidic lab-on-a-chip capillary electrophoresis analyzer capable of ingesting solid, liquid, or gas samples and performing a suite of chemical analyses with parts per trillion sensitivity.

  5. Imbibition of ``Open Capillary'': Fundamentals and Applications

    Science.gov (United States)

    Tani, Marie; Kawano, Ryuji; Kamiya, Koki; Okumura, Ko

    2015-11-01

    Control or transportation of small amount of liquid is one of the most important issues in various contexts including medical sciences or pharmaceutical industries to fuel delivery. We studied imbibition of ``open capillary'' both experimentally and theoretically, and found simple scaling laws for both statics and dynamics of the imbibition, similarly as that of imbibition of capillary tubes. Furthermore, we revealed the existence of ``precursor film,'' which developed ahead of the imbibing front, and the dynamics of it is described well by another scaling law for capillary rise in a corner. Then, to show capabilities of open capillaries, we demonstrated two experiments by fabricating micro mixing devices to achieve (1) simultaneous multi-color change of the Bromothymol blue (BTB) solution and (2) expression of the green florescent protein (GFP). This research was partly supported by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). M. T. is supported by the Japan Society for the Promotion of Science Research Fellowships for Young Scientists.

  6. Shift dynamics of capillary self-alignment

    NARCIS (Netherlands)

    Arutinov, G.; Mastrangeli, M.; Smits, E.C.P.; Heck, G.V.; Schoo, H.F.M.; Toonder, J.J.M. den; Dietzel, A.H.

    2014-01-01

    This paper describes the dynamics of capillary self-alignment of components with initial shift offsets from matching receptor sites. The analysis of the full uniaxial self-alignment dynamics of foil-based mesoscopic dies from pre-alignment to final settling evidenced three distinct, sequential regim

  7. Numerical simulations of capillary barrier field tests

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C.E. [Univ. of Wollongong (Australia); Stormont, J.C. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-12-31

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.

  8. Macroscopic theory for capillary-pressure hysteresis.

    Science.gov (United States)

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

    2015-03-01

    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials. PMID:25646688

  9. Numerical simulations of capillary barrier field tests

    International Nuclear Information System (INIS)

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior

  10. Conversion of the biodiesel by-product glycerol by the non-conventional yeast Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying

    The focus on de veloping new renewable energy in the transportation sector by the EU has boosted the production of biodiesel from rapeseed and other vegetable oils in Europe. This has led to an immense increase in the production of glycerol, which is an inevitable byproduct from the biodiesel...... production process. Since the volume of the glycerol by-product has exceeded the current market need, biodiesel producers are looking for new methods for sustainable glycerol management and improving the competitiveness of the biodiesel industries. The EU Commission funded GLYFINERY project is one initiative...

  11. A comparative evaluation of plasma glycerol and free fatty acids in patients with ischaemic heart disease

    Directory of Open Access Journals (Sweden)

    Singh V

    1979-01-01

    Full Text Available Plasma glycerol concentration was determined in 158 patients admitted to the hospital with acute chest pain. The patients were retrospectively divided into five groups according to their diagnosis, taking into account the presence or absence of myocardial infarc-tion and complicating arrythmias, The plasma glycerol concentra-tion was significantly higher in the group with complicating arrhythmias, irrespective of whether infarction was present or not. Therefore it is proposed that elevation of plasma glycerol may provide an important clue to determine those myocardial ischaemia cases who may develop cardiac arrythmias at a later stage.

  12. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    OpenAIRE

    De Barros Bouchet, M. I.; Matta, C.; Le-Mogne, Th.; Martin, J. Michel; Zhang, Q.; Goddard, W., III; Kano, M; Mabuchi, Y.; J Ye

    2007-01-01

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations us...

  13. Influence of palm oil and glycerol on properties of fish skin gelatin-based films.

    Science.gov (United States)

    Nilsuwan, Krisana; Benjakul, Soottawat; Prodpran, Thummanoon

    2016-06-01

    Properties of fish skin gelatin film incorporated with palm oil at 50 and 75 % (w/w) as affected by glycerol at 0-30 % (w/w) were investigated. Increases in water vapour permeability and elongation at break along with decrease in tensile strength were noticed when levels of glycerol were increased (p palm oil incorporated increased (p palm oil was incorporated. Films added with palm oil had lower glass transition and degradation temperatures than control films. The addition of 75 % palm oil and 10 % glycerol improved water vapour barrier property of fish skin gelatin films without drastic alteration of mechanical properties.

  14. Bioremediation of Parboiled Rice Effluent Supplemented with Biodiesel-Derived Glycerol Using Pichia pastoris X-33

    OpenAIRE

    Diego Gil de los Santos; Carlos Gil Turnes; Fabricio Rochedo Conceição

    2012-01-01

    This paper describes the use of Pichia pastoris X-33 as a bioremediator to reduce the chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and phosphorus (P- P O 4 3 − ), after culture in parboiled rice effluent supplemented with p.a. glycerol or a glycerol by-product of the biodiesel industry. The greatest reduction in the COD (55%), TKN (45%), and P- P O 4 3 − (52%) of the effluent was observed in cultures of P. pastoris X-33 supplemented with 15 g ·L−1 of biodiesel-derived glycerol...

  15. Synthesis and characterization of polyesters derived from glycerol and phthalic acid

    Directory of Open Access Journals (Sweden)

    Danilo Hansen Guimarães

    2007-09-01

    Full Text Available The production of polyester via polycondensation between glycerol and phthalic acid using dibutyltin dilaurate is reported. Three glycerol:phthalic acid molar ratio used for the bulk polymerization were: 2:2; 2:3 and 2:4. FTIR confirmed the esterification of glycerol by the acid for all the polymers. DSC indicated no crystallinity, although the XRD plots indicate a very incipient crystallinity for the polymers containing higher amounts of phthalic anhydride. Scanning electron microscopy results indicates high homogeneity for all the polymers prepared.

  16. Influence of Glycerol Content on Properties of Wheat Gluten/Hydroxyethyl Cellulose Biocomposites

    Institute of Scientific and Technical Information of China (English)

    SONG Yi-hu; ZHENG Qiang; LIU Cheng

    2008-01-01

    Environmentally friendly biocomposites were prepared by blending wheat gluten(WG) as a matrix,hydroxyethyl cellulose(HEC) as a filler,and glycerol as a plasticizer,followed by thermo-molding of the mixture at 120 ℃ for crosslinking the matrix.Moisture absorption,tensile properties,dynamic mechanical analysis,and dynamic theology were evaluated in relation to the glycerol content.Tensile strength and modulus drop dramatically with increasing glycerol content,which is accompanied by significant depression in the glass transition temperature and improvement in the extensibility of the biocomposites.

  17. Microbial Conversion of Waste Glycerol from Biodiesel Production into Value-Added Products

    Directory of Open Access Journals (Sweden)

    Hong Liu

    2013-09-01

    Full Text Available Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable chemicals performed by various bacteria, yeast, fungi, and microalgae are discussed in this review paper, as well as the possibility of extending these conversions to microbial electrochemical technologies.

  18. Investigation on the Adsorption and Photooxidation of Glycerol at TiO2 Nanotubular Arrays

    Directory of Open Access Journals (Sweden)

    Simonetta Palmas

    2012-01-01

    Full Text Available A study is presented on the adsorption of glycerol at TiO2 as well as on its oxidative process during the contemporary water Photoelectro-splitting for hydrogen production. A deepening in the understanding on the working mechanism of the TiO2 nanotubular photoanodes and on the interactions between glycerol and these structures has been gained through photocurrent tests, voltammetric scans, and EIS analysis. A range of wavelength of the incident radiation is investigated from 340 to 400 nm at which the effect of glycerol on the photocurrent is measured. Quantitative analysis of the EIS results is performed by the equivalent circuit approach.

  19. Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

    Science.gov (United States)

    Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2014-08-29

    Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed.

  20. Spectroscopic Approach to Capillary-Alveolar Membrane Damage Induced Acute Lung Injury

    Directory of Open Access Journals (Sweden)

    Jing Wang

    1999-01-01

    Full Text Available BACKGROUND: Acute (or adult respiratory distress syndrome (ARDS is often associated with a high mortality rate in the critical care population. The term acute lung injury (ALI, a primitive phase of ARDS, was introduced by the European and American consensus groups to provide early diagnoses of ARDS. The pathophysiological characterization of ALI/ARDS – an increased pulmonary capillary-alveolar membrane barrier permeability – is generally not included in current intensive care unit diagnosis criteria.

  1. Elasto-capillary collapse of floating structures - Non-linear response of elastic structures under capillary forces

    CERN Document Server

    Adami, N; Roman, B; Bico, J; Caps, H

    2013-01-01

    Flexible rings and rectangle structures floating at the surface of water are prone to deflect under the action of surface pressure induced by the addition of surfactant molecules on the bath. While the frames of rectangles bend inward or outward for any surface pressure difference, circles are only deformed by compression beyond a critical buckling load. However, compressed frames also undergo a secondary buckling instability leading to a rhoboidal shape. Following the pioneering works of \\cite{Hu} and \\cite{Zell}, we describe both experimentally and theoretically the different elasto-capillary deflection and buckling modes as a function of the material parameters. In particular we show how this original fluid structure interaction may be used to probe the adsorption of surfactant molecules at liquid interfaces.

  2. Regional blood flow in the normal and ischemic brain is controlled by arteriolar smooth muscle cell contractility and not by capillary pericytes

    OpenAIRE

    Hill, Robert A.; Tong, Lei; Yuan, Peng; Murikinati, Sasidhar; Gupta, Shobhana; Grutzendler, Jaime

    2015-01-01

    The precise regulation of cerebral blood flow is critical for normal brain function and its disruption underlies many neuropathologies. The extent to which smooth muscle-covered arterioles or pericyte-covered capillaries control vasomotion during neurovascular coupling remains controversial. We found that capillary pericytes in mice and humans do not express smooth muscle actin and are morphologically and functionally distinct from adjacent precapillary smooth muscle cells (SMCs). Using optic...

  3. A complete soil hydraulic model accounting for capillary and adsorptive water retention, capillary and film conductivity, and hysteresis

    NARCIS (Netherlands)

    Sakai, Masaru; Van Genuchten, Martinus Th; Alazba, A. A.; Setiawan, Budi Indra; Minasny, Budiman

    2015-01-01

    A soil hydraulic model that considers capillary hysteretic and adsorptive water retention as well as capillary and film conductivity covering the complete soil moisture range is presented. The model was obtained by incorporating the capillary hysteresis model of Parker and Lenhard into the hydraulic

  4. Wall slip behavior of polymer melts on capillary rheometer

    Institute of Scientific and Technical Information of China (English)

    廖华勇; 谭中欣; 邹国享; 丁永红; 陶国良

    2008-01-01

    Wall slip behavior of three commercial polymer melts polypropylene(iPP),low-density polyethylene(LDPE)(branched chains) and high-density polyethylene(HDPE)(linear chains) were studied by using a capillary rheometer with twin bores at different temperatures.The results show that a sudden first-stick-then-slip transition was observed for HDPE and a first-slip-then-stick transition was observed for LDPE and iPP as the shear rate sweep was done in an increased order,which shows that the chain structure has an obvious effect on the wall slip behavior of polymers.The critical shear stress for the onset of stick-slip transition increases linearly with temperature for HDPE,which accords with the disentanglement mechanism proposed by Brochard and de Gennes.While the extrapolation length used to quantify the magnitude of the transition remains about 0.05-0.09 mm for HDPE at 150-230 ℃.Also the relationship between the critical shear stress for the onset of wall slip and the molecular mass for polymer samples agrees with the disentanglement model of Brochard and de Gennes.The onset of slip-stick transition for LDPE and iPP at a critical shear stress may be interpreted as the shear thinning of the polymer chains at high shear rates,preventing further development of wall slip behavior.

  5. Method of making tapered capillary tips with constant inner diameters

    Science.gov (United States)

    Kelly, Ryan T.; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2009-02-17

    Methods of forming electrospray ionization emitter tips are disclosed herein. In one embodiment, an end portion of a capillary tube can be immersed into an etchant, wherein the etchant forms a concave meniscus on the outer surface of the capillary. Variable etching rates in the meniscus can cause an external taper to form. While etching the outer surface of the capillary wall, a fluid can be flowed through the interior of the capillary tube. Etching continues until the immersed portion of the capillary tube is completely etched away.

  6. Synthesis of high purity monoglycerides from crude glycerol and palm stearin

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2008-07-01

    Full Text Available The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process werefound to be a reaction temperature of 200oC with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction timeof 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared withthe glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glyceroland crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed byadding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved byusing isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35oC. A purity notexceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.

  7. Insect glycerol transporters evolved by functional co-option and gene replacement.

    Science.gov (United States)

    Finn, Roderick Nigel; Chauvigné, François; Stavang, Jon Anders; Belles, Xavier; Cerdà, Joan

    2015-01-01

    Transmembrane glycerol transport is typically facilitated by aquaglyceroporins in Prokaryota and Eukaryota. In holometabolan insects however, aquaglyceroporins are absent, yet several species possess polyol permeable aquaporins. It thus remains unknown how glycerol transport evolved in the Holometabola. By combining phylogenetic and functional studies, here we show that a more efficient form of glycerol transporter related to the water-selective channel AQP4 specifically evolved and multiplied in the insect lineage, resulting in the replacement of the ancestral branch of aquaglyceroporins in holometabolan insects. To recapitulate this evolutionary process, we generate specific mutants in distantly related insect aquaporins and human AQP4 and show that a single mutation in the selectivity filter converted a water-selective channel into a glycerol transporter at the root of the crown clade of hexapod insects. Integration of phanerozoic climate models suggests that these events were associated with the emergence of complete metamorphosis and the unparalleled radiation of insects. PMID:26183829

  8. Enzymatic coproduction of biodiesel and glycerol carbonate from soybean oil and dimethyl carbonate.

    Science.gov (United States)

    Seong, Pil-Je; Jeon, Byoung Wook; Lee, Myunggu; Cho, Dae Haeng; Kim, Duk-Ki; Jung, Kwang S; Kim, Seung Wook; Han, Sung Ok; Kim, Yong Hwan; Park, Chulhwan

    2011-05-01

    The enzymatic coproduction of biodiesel and glycerol carbonate by the transesterification of soybean oil was studied using lipase as catalyst in organic solvent. To produce biodiesel and glycerol carbonate simultaneously, experiments were designed sequentially. Enzyme screening, the molar ratio of dimethyl carbonate (DMC) to soybean oil, reaction temperature and solvent effects were investigated. The results of enzyme screening, at 100 g/L Novozym 435 (immobilized Candida antarctica lipase B), biodiesel and glycerol carbonate showed conversions of 58.7% and 50.7%, respectively. The optimal conditions were 60 °C, 100 g/L Novozym 435, 6.0:1 molar ratio with tert-butanol as solvent: 84.9% biodiesel and 92.0% glycerol carbonate production was achieved. PMID:22113023

  9. Selective liquid phase oxidation of glycerol to glyceric acid over novel supported Pt catalysts

    Directory of Open Access Journals (Sweden)

    Sproge Elina

    2013-01-01

    Full Text Available Several supported platinum catalysts were prepared by extractive-pyrolytic method for the selective glyceric acid production from glycerol. Al2O3, Y2O3, Lu2O3, ZrO2-Y2O3 TiO2, SG, Fe2O3, γ-AlO(OH and C were used as catalyst supports, glycerol oxidation was carried out in the alkaline solutions and oxygen was used as oxidant. The optimal catalyst preparation parameters and glycerol oxidation conditions to obtain glyceric acid were determined. The best result (selectivity to glyceric acid 57% with glycerol conversion 92% was achieved in the presence of 4.8%Pt/Al2O3 catalyst.

  10. AN ALTERNATIVE METHODOLOGY OF DETERMINING FEED SORTING IN TRANSITION DAIRY COWS FED GLYCEROL

    Directory of Open Access Journals (Sweden)

    Eduardo Rodrigues de Carvalho

    2010-12-01

    Full Text Available The objective of this study was to compare the standard methodologywith an alternative method to determine feed sorting in dairy cows during the transition period. Twenty-six Holstein multiparous cows were paired by expected calving date and fed diets containing either glycerol or high moisture corn from -28 through +56 days relative to calving (DRTC. Feed sorting was determined on -16, -9, +9, +15 and +51 DRTC in two different ways. Firstly, it was determinedas the actual intake of each screen of the Penn State Particle Separator (PSPS consumed between 0-4, 4-8, 8-12 and 12-24 hours post feeding, and expressed as a percentage of the predicted intake of that correspondent screen. Secondly, by measuring the particle size distribution of feed consumed between 0-4, 4-8, 8-12 and 12-24 hours post feeding. The total mixed ration (TMR at feeding and at each time post feeding was separated by size using the 3-screen (19, 8, and 1.18 mm Penn State Particle Separator (PSPS to yield long (>19 mm, medium (8 mm, short (1.18 mm, and fine particles (19 mm and reduced (P1.18 mm and fine particles (0.05 the proportion of DM% retained as medium particles (8 mm. Cows fed prepartum glycerol increased (P19 mm according to the standard methodology (77.2 vs. 101.5%, control vs. glycerol and also in the alternative methodology (9.2 vs. 17.8%, control vs. glycerol. Cows fed prepartum glycerol discriminated against (P1.18 mm in the standard methodology (102.6 vs. 94.2%, control vs. glycerol as well as in the alternative methodology (42 vs. 37.3%, control vs. glycerol. There was no response (P>0.05 of diet on feed sorting of fine particles (8 mm according to the standard methodology (108.6 vs. 116.5%, control vs. glycerol, but did not (P>0.05 according to the alternative methodology. Cows fed postpartum glycerol discriminated against (P1.18 mm according to the standard methodology (100.6 vs. 96.6%, control vs. glycerol, but did not (P>0.05 according to the alternative

  11. Glass polymorphism in glycerol-water mixtures: I. A computer simulation study.

    Science.gov (United States)

    Jahn, David A; Wong, Jessina; Bachler, Johannes; Loerting, Thomas; Giovambattista, Nicolas

    2016-04-28

    We perform out-of-equilibrium molecular dynamics (MD) simulations of water-glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA-HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration χ(g) = 0-13% and find that, for the present mixture models and rates, the LDA-HDA transformation is detectable up to χ(g) ≈ 5%. As the concentration increases, the density of the starting glass (i.e., LDA at approximately χ(g) ≤ 5%) rapidly increases while, instead, the density of HDA remains practically constant. Accordingly, the LDA state and hence glass polymorphism become inaccessible for glassy mixtures with approximately χ(g) > 5%. We present an analysis of the molecular-level changes underlying the LDA-HDA transformation. As observed in pure glassy water, during the LDA-to-HDA transformation, water molecules within the mixture approach each other, moving from the second to the first hydration shell and filling the first interstitial shell of water molecules. Interestingly, similar changes also occur around glycerol OH groups. It follows that glycerol OH groups contribute to the density increase during the LDA-HDA transformation. An analysis of the hydrogen bond (HB)-network of the mixtures shows that the LDA-HDA transformation is accompanied by minor changes in the number of HBs of water and glycerol. Instead, large changes in glycerol and water coordination numbers occur. We also perform a detailed analysis of the effects that

  12. Capillary Interactions between a Probe Tip and a Nanoparticle

    Institute of Scientific and Technical Information of China (English)

    SUN Li-Ning; WANG Le-Feng; RONG Wei-Bin

    2008-01-01

    To understand capillary interactions between probe tips and nanoparticles under ambient conditions,a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases.It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force.The capillary force decreases with the increasing separation distances,and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances.The applicability of the symmetric meniscus approximation is discussed.

  13. Lipid and citric acid production by wild yeasts grown in glycerol.

    Science.gov (United States)

    Souza, Karla Silva Teixeira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

    2014-04-01

    In this study, crude glycerol was used as a carbon source in the cultivation of wild yeasts, aiming for the production of microbial lipids and citric acid. Forty yeasts of different sources were tested concerning their growth in crude and commercial glycerol. Four yeasts (Lidnera saturnus UFLA CES-Y677, Yarrowia lipolytica UFLA CM-Y9.4, Rhodotorula glutinis NCYC 2439, and Cryptococcus curvatus NCYC 476) were then selected owing to their ability to grow in pure (OD600 2.133, 1.633, 2.055, and 2.049, respectively) and crude (OD600 2.354, 1.753, 2.316, and 2.281, respectively) glycerol (10%, 20%, and 30%). Y. lipolytica UFLA CM-Y9.4 was selected for its ability to maintain cell viability in concentrations of 30% of crude glycerol, and high glycerol intake (18.907 g/l). This yeast was submitted to lipid production in 30 g/l of crude glycerol, and therefore obtained 63.4% of microbial lipids. In the fatty acid profile, there was a predominance of stearic (C18:0) and palmitic (C16:0) acids in the concentrations of 87.64% and 74.67%, respectively. We also performed optimization of the parameters for the production of citric acid, which yielded a production of 0.19 g/l of citric acid in optimum conditions (38.4 g/l of crude glycerol, agitation of 184 rpm, and temperature of 30°C). Yarrowia lipolytica UFLA CM-Y9.4 presented good lipid production when in the concentration of 30 g/l of glycerol. These data may be used for production in large quantities for the application of industrial biodiesel.

  14. OPTIMAL FEED STRATEGY FOR FED-BATCH GLYCEROL FERMENTATION DETERMINED BY MAXIMUM PRINCIPLE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    1 IntroductionGlycerol fed-batch fermentation is attractive tocommercial application since it can control theglucose concentration by changing the feed rate andget a high glycerol yield, therefore it is essential todevelop an optimal glucose feed strategy. For mostof fed-batch fermentation, optimization of feed ratewas based on Pontryagin's maximum principle [if.Since the term of feed rate appears linearly in theHamiltonian, the optimal feed rate profile usuallyconsists of ba,lg-bang intervals and singular ...

  15. Influence of palm oil and glycerol on properties of fish skin gelatin-based films.

    Science.gov (United States)

    Nilsuwan, Krisana; Benjakul, Soottawat; Prodpran, Thummanoon

    2016-06-01

    Properties of fish skin gelatin film incorporated with palm oil at 50 and 75 % (w/w) as affected by glycerol at 0-30 % (w/w) were investigated. Increases in water vapour permeability and elongation at break along with decrease in tensile strength were noticed when levels of glycerol were increased (p water vapour barrier property of fish skin gelatin films without drastic alteration of mechanical properties. PMID:27478227

  16. Enhanced enzymatic activity of glycerol-3-phosphate dehydrogenase from the cryophilic Saccharomyces kudriavzevii.

    Directory of Open Access Journals (Sweden)

    Bruno M Oliveira

    Full Text Available During the evolution of the different species classified within the Saccharomyces genus, each one has adapted to live in different environments. One of the most important parameters that have influenced the evolution of Saccharomyces species is the temperature. Here we have focused on the study of the ability of certain species as Saccharomyces kudriavzevii to grow at low temperatures, in contrast to Saccharomyces cerevisiae. We observed that S. kudriavzevii strains isolated from several regions are able to synthesize higher amounts of glycerol, a molecule that has been shown to accumulate in response to freeze and cold stress. To explain this observation at the molecular level we studied the expression of glycerol biosynthetic pathway genes and we observed a higher expression of GPD1 gene in S. kudriavzevii compared to S. cerevisiae in micro-vinification conditions. We observed higher enzymatic activity of Gpd1p in S. kudriavzevii in response to osmotic and cold stress. Also, we determined that S. kudriavzevii Gpd1p enzyme presents increased catalytic properties that will contribute to increase glycerol production. Finally, we evaluated the glycerol production with S. cerevisiae, S. kudriavzevii or a recombinant Gpd1p variant in the same background and observed that the S. kudriavzevii enzyme produced increased glycerol levels at 12 or 28°C. This suggests that glycerol is increased in S. kudriavzevii mainly due to increased V max of the Gpd1p enzyme. All these differences indicate that S. kudriavzevii has changed the metabolism to promote the branch of the glycolytic pathway involved in glycerol production to adapt to low temperature environments and maintain the NAD(+/NADH ratio in alcoholic fermentations. This knowledge is industrially relevant due to the potential use, for example, of S. cerevisiae-S. kudriavzevii hybrids in the wine industry where glycerol content is an important quality parameter.

  17. Development of glycerol-based carbon materials for environmental catalytic applications in advanced oxidation processes

    OpenAIRE

    Gomes, Helder; Ribeiro, Rui; Silva, Adrián; Pinho, Teresa; Figueiredo, José; Faria, Joaquim

    2013-01-01

    A glycerol-based carbon material was initially produced by partial carbonization of glycerol with sulphuric acid followed by calcination under inert atmosphere. This material, characterized by high thermal stability, low ash content, non-porous structure and basic character, was further activated in air atmosphere at different temperatures (from 150 to 350 oC), resulting in materials with less basic character, due to the incorporation of oxygenated surface groups, and to a notorious evolution...

  18. Adaptation of acidogenic sludge to increasing glycerol concentrations for biohydrogen production.

    Science.gov (United States)

    Tapia-Venegas, E; Cabrol, L; Brandhoff, B; Hamelin, J; Trably, E; Steyer, J P; Ruiz-Filippi, G

    2015-10-01

    Hydrogen is a promising alternative as an energetic carrier and its production by dark fermentation from wastewater has been recently proposed, with special attention to crude glycerol as potential substrate. In this study, two different feeding strategies were evaluated for replacing the glucose substrate by glycerol substrate: a one-step strategy (glucose was replaced abruptly by glycerol) and a step-by-step strategy (progressive decrease of glucose concentration and increase of glycerol concentration from 0 to 5 g L(-1)), in a continuous stirred tank reactor (12 h of hydraulic retention time (HRT), pH 5.5, 35 °C). While the one-step strategy led to biomass washout and unsuccessful H2 production, the step-by-step strategy was efficient for biomass adaptation, reaching acceptable hydrogen yields (0.4 ± 0.1 molH2 mol(-1) glycerol consumed) around 33 % of the theoretical yield independently of the glycerol concentration. Microbial community structure was investigated by single-strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) fingerprinting techniques, targeting either the total community (16S ribosomal RNA (rRNA) gene) or the functional Clostridium population involved in H2 production (hydA gene), as well as by 454 pyrosequencing of the total community. Multivariate analysis of fingerprinting and pyrosequencing results revealed the influence of the feeding strategy on the bacterial community structure and suggested the progressive structural adaptation of the community to increasing glycerol concentrations, through the emergence and selection of specific species, highly correlated to environmental parameters. Particularly, this work highlighted an interesting shift of dominant community members (putatively responsible of hydrogen production in the continuous stirred tank reactor (CSTR)) according to the gradient of glycerol proportion in the feed, from the family Veillonellaceae to the genera Prevotella and

  19. Optimization of glycerol-organosolv pretreatment for improving enzymatic saccharification of Eucalyptus wood

    OpenAIRE

    Romaní, Aloia; Ruíz, Héctor A.; Pereira, Francisco B.; J.A. Teixeira; Domingues, Lucília

    2014-01-01

    This work contributes to the improvement of biomass pretreatment technologies and shows an efficient pretreatment by glycerol -water with a good lignocellulose biomass fractionation and an enhanced enzymatic susceptibility of pretreated solid. The results show that solubilized wood fraction after glycerol treatment is composed by 15.9 and 13.2 g of lignin and xylose / 100 g of raw material in the liquid phase, respectively, whereas the solid phase was hydrolyzed by enzymes (achieving up to 90...

  20. Biosynthesis of poly(3-hydroxypropionate) from glycerol using engineered Klebsiella pneumoniae strain without vitamin B12

    OpenAIRE

    Feng, Xinjun; Xian, Mo; Liu, Wei; Xu, Chao; Zhang, Haibo; Zhao, Guang

    2015-01-01

    Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. Previous studies demonstrated that engineered Escherichia coli strains can produce P3HP with supplementation of expensive vitamin B12. The present study examined the production of P3HP from glycerol in the recombinant Klebsiella pneumoniae strain, which naturally synthesizes vitamin B12. The genes glycerol dehydratase and its reactivation factor (dhaB123, gdrA, and gdrB from K. pneumoniae), aldehyde dehydroge...

  1. Glycerol-Induced Membrane Stiffening: The Role of Viscous Fluid Adlayers

    OpenAIRE

    Pocivavsek, Luka; Gavrilov, Kseniya; Cao, Kathleen D.; Chi, Eva Y.; Li, Dongxu; Lin, Binhua; Meron, Mati; Majewski, Jaroslaw; Lee, Ka Yee C.

    2011-01-01

    Lipid interfaces, ranging from cell membranes to thin surfactant layers that stabilize lung alveoli, are integral to living systems. Such interfaces are often subjected to mechanical forces, and because of their membrane-like geometry, they can easily deform by bending into localized folds. In this work, we explore the role of small molecules (i.e., glycerol) on the mechanical stability of model lung surfactant monolayers. We demonstrate that the presence of glycerol increases local monolayer...

  2. Effect of the initial glycerol concentration in the medium on the xanthan biosynthesis

    OpenAIRE

    Rončević Zorana Z.; Bajić Bojana Ž.; Grahovac Jovana A.; Dodić Siniša N.; Dodić Jelena M.

    2014-01-01

    This study is concerned with the effect of different initial glycerol concentrations in the medium on xanthan production by Xanthomonas campestris ATCC 13951. Xanthan biosynthesis was carried out in batch mode under aerobic conditions at a temperature of 30oC and agitation rate of 150 rpm for 7 days. The process efficiency was estimated based on the values of raw xanthan yield, average molecular weight of the polymer and residual content of glycerol, total ...

  3. The study of glycerol-based fermentation and broth downstream by nanofiltration

    Directory of Open Access Journals (Sweden)

    Gryta Marek

    2014-12-01

    Full Text Available In this work, the glycerol fermentation was carried out using Citrobacter freundii bacteria. The influence of glycerol and metabolites concentrations, and the pH changes on the efficiency of 1,3-propanediol production, during batch and fed-batch processes, was presented. The nanofiltration was used for the separation of obtained post-fermentation solutions. The resulted 1,3-PD solutions were significantly desalted, which may facilitate further downstream processes during 1,3-PD production.

  4. Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces.

    Science.gov (United States)

    Bradley-Shaw, Joshua L; Camp, Philip J; Dowding, Peter J; Lewtas, Ken

    2016-08-01

    The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of the fluid is characterized in various ways, and the differences between systems with nonaggregated GMO and with preformed GMO reverse micelles are examined. Preformed reverse micelles are metastable under static conditions in all systems. In n-heptane under shear conditions, with or without water, preformed GMO reverse micelles remain intact and adsorb onto one surface or another, becoming surface micelles. In dry toluene, preformed reverse micelles break apart under shear, while in the presence of water, the reverse micelles survive and become surface micelles. In all systems under static and shear conditions, nonaggregated GMO adsorbs onto both surfaces with roughly equal probability. Added water is strongly associated with the GMO, irrespective of shear or the form of the added GMO. In all cases, with increasing shear rate, the GMO molecules flatten on the surface, and the kinetic friction coefficient increases. Under low-shear conditions, the friction is insensitive to the form of the GMO added, whereas the presence of water is found to lead to a small reduction in friction. Under high-shear conditions, the presence of reverse micelles leads to a significant reduction in friction, whereas the presence of water increases the friction in n-heptane and decreases the friction in toluene. PMID:27429247

  5. Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces.

    Science.gov (United States)

    Bradley-Shaw, Joshua L; Camp, Philip J; Dowding, Peter J; Lewtas, Ken

    2016-08-01

    The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of the fluid is characterized in various ways, and the differences between systems with nonaggregated GMO and with preformed GMO reverse micelles are examined. Preformed reverse micelles are metastable under static conditions in all systems. In n-heptane under shear conditions, with or without water, preformed GMO reverse micelles remain intact and adsorb onto one surface or another, becoming surface micelles. In dry toluene, preformed reverse micelles break apart under shear, while in the presence of water, the reverse micelles survive and become surface micelles. In all systems under static and shear conditions, nonaggregated GMO adsorbs onto both surfaces with roughly equal probability. Added water is strongly associated with the GMO, irrespective of shear or the form of the added GMO. In all cases, with increasing shear rate, the GMO molecules flatten on the surface, and the kinetic friction coefficient increases. Under low-shear conditions, the friction is insensitive to the form of the GMO added, whereas the presence of water is found to lead to a small reduction in friction. Under high-shear conditions, the presence of reverse micelles leads to a significant reduction in friction, whereas the presence of water increases the friction in n-heptane and decreases the friction in toluene.

  6. Yeast cells with impaired drug resistance accumulate glycerol and glucose.

    Science.gov (United States)

    Dikicioglu, Duygu; Oc, Sebnem; Rash, Bharat M; Dunn, Warwick B; Pir, Pınar; Kell, Douglas B; Kirdar, Betul; Oliver, Stephen G

    2014-01-01

    Multiple drug resistance (MDR) in yeast is effected by two major superfamilies of membrane transporters: the major facilitator superfamily (MFS) and the ATP-binding cassette (ABC) superfamily. In the present work, we investigated the cellular responses to disruptions in both MFS (by deleting the transporter gene, QDR3) and ABC (by deleting the gene for the Pdr3 transcription factor) transporter systems by growing diploid homozygous deletion yeast strains in glucose- or ammonium-limited continuous cultures. The transcriptome and the metabolome profiles of these strains, as well as the flux distributions in the optimal solution space, reveal novel insights into the underlying mechanisms of action of QDR3 and PDR3. Our results show how cells rearrange their metabolism to cope with the problems that arise from the loss of these drug-resistance genes, which likely evolved to combat chemical attack from bacterial or fungal competitors. This is achieved through the accumulation of intracellular glucose, glycerol, and inorganic phosphate, as well as by repurposing genes that are known to function in other parts of metabolism in order to minimise the effects of toxic compounds. PMID:24157722

  7. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs.

    Science.gov (United States)

    Hedlund, Brian P; Paraiso, Julienne J; Williams, Amanda J; Huang, Qiuyuan; Wei, Yuli; Dijkstra, Paul; Hungate, Bruce A; Dong, Hailiang; Zhang, Chuanlun L

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31-95°C; pH: 6.8-10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS(-)) and positively with properties of oxygenated, low temperature sites (O2, NO(-) 3). Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤70°C).

  8. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs in U.S. Great Basin hot springs

    Directory of Open Access Journals (Sweden)

    Brian P. Hedlund

    2013-08-01

    Full Text Available Branched glycerol dialkyl glycerol tetraethers (bGDGTs are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31-95°C; pH: 6.8-10.7. bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal. The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤ 70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS- and positively with properties of oxygenated, low temperature sites (O2, NO3-. Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤ 70°C.

  9. Glycerol assimilation and production of 1,3-propanediol by Citrobacter amalonaticus Y19.

    Science.gov (United States)

    Ainala, Satish Kumar; Ashok, Somasundar; Ko, Yeounjoo; Park, Sunghoon

    2013-06-01

    Citrobacter amalonaticus Y19 (Y19) was isolated because of its ability for carbon monoxide-dependent hydrogen production (water-gas shift reaction). This paper reports the assimilation of glycerol and the production of 1,3-propanediol (1,3-PDO) by Y19. Genome sequencing revealed that Y19 contained the genes for the utilization of glycerol and 1,2-propanediol (pdu operon) along with those for the synthesis of coenzyme B12 (cob operon). On the other hand, it did not possess the genes for the fermentative metabolism of glycerol of Klebsiella pneumoniae, which consists of both the oxidative (dhaD and dhaK) and reductive (dhaB and dhaT) pathways. In shake-flask cultivation under aerobic conditions, Y19 could grow well with glycerol as the sole carbon source and produced 1,3-PDO. The level of 1,3-PDO production was improved when vitamin B12 was added to the culture medium under aerobic conditions. Under anaerobic conditions, cell growth and 1,3-PDO production on glycerol was also possible, but only when an exogenous electron acceptor, such as nitrate or fumarate, was added. This is the first report of the glycerol metabolism and 1,3-PDO production by C. amalonaticus Y19.

  10. Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

    Science.gov (United States)

    Maru, Biniam T; Constanti, Magda; Stchigel, Alberto M; Medina, Francesc; Sueiras, Jesus E

    2013-01-01

    Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol.

  11. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    Science.gov (United States)

    Schrader, Alex M.; Cheng, Chi-Yuan; Israelachvili, Jacob N.; Han, Songi

    2016-07-01

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  12. Gas-phase dehydration of glycerol over commercial Pt/γ-Al2O3 catalysts

    Institute of Scientific and Technical Information of China (English)

    Sergey Danov; Anton Esipovich; Artem Belousov; Anton Rogozhin

    2015-01-01

    Gas-phase dehydration of glycerol to produce acrolein was investigated over commercial catalysts based onγ-Al2O3, viz. A-64, A-56, I-62, AP-10, AP-56, AP-64 and KR-104. To understand the effect of Cl−anions, HCl-impregnated sup-ports have been investigated in the dehydration reaction of glycerol at 375 °C. For comparison, various H-zeolites were also examined. It was found that the glycerol conversion over the solid acid catalysts was strongly dependent on their acidity and surface area. And the relationship between the catalytic activity and the acidity of the catalysts was discussed. The outstanding properties of Pt/γ-Al2O3 catalyst systems for the dehydration of glycerol were revealed. Pt/γ-Al2O3 catalyst (AP-64) showed the highest catalytic activity after 50 h of reaction with an acrolein selectivity of 65%at a conversion of glycerol of 90%. Based on these results, catalysts based onγ-Al2O3 appear to be most promising for gas phase dehydration of glycerol.

  13. Identification of positive regulators of the yeast fps1 glycerol channel.

    Directory of Open Access Journals (Sweden)

    Sara E Beese

    2009-11-01

    Full Text Available The yeast Fps1 protein is an aquaglyceroporin that functions as the major facilitator of glycerol transport in response to changes in extracellular osmolarity. Although the High Osmolarity Glycerol pathway is thought to have a function in at least basal control of Fps1 activity, its mode of regulation is not understood. We describe the identification of a pair of positive regulators of the Fps1 glycerol channel, Rgc1 (Ypr115w and Rgc2 (Ask10. An rgc1/2Delta mutant experiences cell wall stress that results from osmotic pressure associated with hyper-accumulation of glycerol. Accumulation of glycerol in the rgc1/2Delta mutant results from a defect in Fps1 activity as evidenced by suppression of the defect through Fps1 overexpression, failure to release glycerol upon hypo-osmotic shock, and resistance to arsenite, a toxic metalloid that enters the cell through Fps1. Regulation of Fps1 by Rgc1/2 appears to be indirect; however, evidence is presented supporting the view that Rgc1/2 regulate Fps1 channel activity, rather than its expression, folding, or localization. Rgc2 was phosphorylated in response to stresses that lead to regulation of Fps1. This stress-induced phosphorylation was partially dependent on the Hog1 MAPK. Hog1 was also required for basal phosphorylation of Rgc2, suggesting a mechanism by which Hog1 may regulate Fps1 indirectly.

  14. Microbial utilization of crude glycerol for the production of value-added products.

    Science.gov (United States)

    Dobson, Rosemary; Gray, Vincent; Rumbold, Karl

    2012-02-01

    Energy fuels for transportation and electricity generation are mainly derived from finite and declining reserves of fossil hydrocarbons. Fossil hydrocarbons are also used to produce a wide range of organic carbon-based chemical products. The current global dependency on fossil hydrocarbons will not be environmentally or economically sustainable in the long term. Given the future pessimistic prospects regarding the complete dependency on fossil fuels, political and economic incentives to develop carbon neutral and sustainable alternatives to fossil fuels have been increasing throughout the world. For example, interest in biodiesel has undergone a revival in recent times. However, the disposal of crude glycerol contaminated with methanol, salts, and free fatty acids as a by-product of biodiesel production presents an environmental and economic challenge. Although pure glycerol can be utilized in the cosmetics, tobacco, pharmaceutical, and food industries (among others), the industrial purification of crude glycerol is not economically viable. However, crude glycerol could be used as an organic carbon substrate for the production of high-value chemicals such as 1,3-propanediol, organic acids, or polyols. Microorganisms have been employed to produce such high-value chemicals and the objective of this article is to provide an overview of studies on the utilization of crude glycerol by microorganisms for the production of economically valuable products. Glycerol as a by-product of biodiesel production could be used a feedstock for the manufacture of many products that are currently produced by the petroleum-based chemical industry. PMID:21948485

  15. Chronic metabolic responses of postpartal dairy cows to subcutaneous glucagon injections, oral glycerol, or both.

    Science.gov (United States)

    Osman, M A; Allen, P S; Bobe, G; Coetzee, J F; Abuzaid, A; Koehler, K; Beitz, D C

    2010-08-01

    We examined the long-term effects of daily subcutaneous injections of 15 mg of glucagon during the first 14 d postpartum with or without coadministration of 400 mL of pure glycerol orally on blood metabolites and hormones and liver composition of Holstein dairy cows during early lactation. Fourteen multiparous cows with body condition score of >or=3.5 points (1-5 point scale) were assigned randomly to one of 4 treatment groups-saline, glucagon, glycerol, or glucagon plus glycerol. Fatty liver syndrome was induced by feeding cows a dry-cow ration supplemented with 6 kg of cracked corn daily during the last 6 wk of the dry period. Compared with saline treatment (n=3), coadministration of glucagon and glycerol (n=4) increased plasma glucose and insulin and decreased plasma nonesterified fatty acid concentrations in both treatment weeks, whereas glucagon alone (n=3) produced similar changes plus a decrease in plasma beta-hydroxybutyrate in the second week only. No significant changes were observed for the glycerol alone treatment (n=4). We conclude that a single daily dose of glycerol for the first 14 d postpartum may potentiate the action of glucagon in the first treatment days to alleviate some symptoms of fatty liver syndrome, such as the increase in plasma nonesterified fatty acids and the decrease in plasma glucose and insulin, in Holstein dairy cows after parturition.

  16. The citric acid production from raw glycerol by Yarrowia lipolytica yeast and its regulation.

    Science.gov (United States)

    Morgunov, Igor G; Kamzolova, Svetlana V; Lunina, Julia N

    2013-08-01

    The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients (nitrogen, phosphorus, or sulfur), 28 °C, pH 5.0, dissolved oxygen concentration (pO₂) of 50 % (of air saturation), and pulsed addition of glycerol from 20 to 80 g L⁻¹ depending on the rate of medium titration. Under optimal conditions of fed-batch cultivation, in the medium with pure glycerol, strain Y. lipolytica NG40/UV7 produced 115 g L⁻¹ of CA with the mass yield coefficient of 0.64 g g⁻¹ and isocitric acid (ICA) amounted to 4.6 g L⁻¹; in the medium with raw glycerol, CA production was 112 g L⁻¹ with the mass yield coefficient of 0.90 g g⁻¹ and ICA amounted to 5.3 g L⁻¹. Based on the activities of enzymes involved in the initial stages of raw glycerol assimilation, the tricarboxylic acid cycle and the glyoxylate cycle, the mechanism of increased CA yield from glycerol-containing substrates in Y. lipolytica yeast was explained.

  17. Alternative Glycerol Balance Strategies among Saccharomyces Species in Response to Winemaking Stress

    Science.gov (United States)

    Pérez-Torrado, Roberto; Oliveira, Bruno M.; Zemančíková, Jana; Sychrová, Hana; Querol, Amparo

    2016-01-01

    Production and balance of glycerol is essential for the survival of yeast cells in certain stressful conditions as hyperosmotic or cold shock that occur during industrial processes as winemaking. These stress responses are well-known in S. cerevisiae, however, little is known in other phylogenetically close related Saccharomyces species associated with natural or fermentation environments such as S. uvarum, S. paradoxus or S. kudriavzevii. In this work we have investigated the expression of four genes (GPD1, GPD2, STL1, and FPS1) crucial in the glycerol pool balance in the four species with a biotechnological potential (S. cerevisiae; S. paradoxus; S. uvarum; and S. kudriavzevii), and the ability of strains to grow under osmotic and cold stresses. The results show different pattern and level of expression among the different species, especially for STL1. We also studied the function of Stl1 glycerol symporter in the survival to osmotic changes and cell growth capacity in winemaking environments. These experiments also revealed a different functionality of the glycerol transporters among the different species studied. All these data point to different strategies to handle glycerol accumulation in response to winemaking stresses as hyperosmotic or cold-hyperosmotic stress in the different species, with variable emphasis in the production, influx, or efflux of glycerol. PMID:27064588

  18. The salt relations of Dunaliella. Further observations on glycerol production and its regulation.

    Science.gov (United States)

    Borowitzka, L J; Kessly, D S; Brown, A D

    1977-05-13

    Dunaliella tertiolecta (marine) and D. viridis (halophilic) were each trained by serial transfer to grow at salt concentrations previously regarded as the other's domain. D. viridis then had a salt optimum at 1.0-1.5 M sodium chloride whereas that for D. tertiolecta was less than 0-2 M. Nevertheless D. tertiolecta grew faster than the halophil at all salt concentrations up to 3.5 M, the highest at which they were compared. Both species accumulate glycerol, which is necessary for growth at elevated salinities and which responds in its content to water activity (aw) rather than specifically to salt concentration. Variation in glycerol content is a metabolic process which occurs in the dark from accumulated starch as well as photosynthetically. Regulation of glycerol content by aw does not require protein synthesis. The NADP-specific glycerol dehydrogenase of each of the algae is likely to be directly involved in the regulation of glycerol content. Kinetic studies, together with those described in an earlier publication, show that the enzyme has regulatory properties and that both glycerol and dihydroxyacetone act as effectors as well as reactants. A mechanism of the reaction is tentatively proposed. PMID:19000

  19. Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

    Science.gov (United States)

    Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

    2015-01-01

    Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

  20. Fermentation of residual glycerol by Clostridium acetobutylicum ATCC 824 in pure and mixed cultures.

    Science.gov (United States)

    Dams, Rosemeri I; Guilherme, Alexandre A; Vale, Maria S; Nunes, Vanja F; Leitão, Renato C; Santaella, Sandra T

    2016-12-01

    The aim of this research was to estimate the production of hydrogen, organic acids and alcohols by the strain of Clostridium acetobutylicum ATCC 824 using residual glycerol as a carbon source. The experiments were carried out in pure and mixed cultures in batch experiments. Three different sources of inocula for mixed culture were used. Ruminal liquid from goats and sludge collected from two upflow anaerobic sludge blanket reactors treating municipal wastewater and brewery effluent were tested for hydrogen, organic acids and alcohols production with or without C. acetobutylicum ATCC 824. The main detected end-products from the glycerol fermentation were hydrogen, organic acids (acetic, propionic, butyric and caproic) and alcohol (ethanol and 1,3-propanediol - 1,3PD). High hydrogen (0.44 mol H2/mol glycerol consumed) and 1,3PD (0.32 mol 1,3PD/mol glycerol consumed) yields were obtained when the strain C. acetobutylicum ATCC 824 was bioaugmented into the sludge from municipal wastewater using 5 g/L of glycerol. Significant concentrations of n-caproic acid were detected in the ruminal liquid when amended with C. acetobutylicum ATCC 824. The results suggest that glycerol can be used for the generation of H2, 1,3PD and n-caproic acid using C. acetobutylicum ATCC 824 as agent in pure or mixed cultures.

  1. Effect of the initial glycerol concentration in the medium on the xanthan biosynthesis

    Directory of Open Access Journals (Sweden)

    Rončević Zorana Z.

    2014-01-01

    Full Text Available This study is concerned with the effect of different initial glycerol concentrations in the medium on xanthan production by Xanthomonas campestris ATCC 13951. Xanthan biosynthesis was carried out in batch mode under aerobic conditions at a temperature of 30oC and agitation rate of 150 rpm for 7 days. The process efficiency was estimated based on the values of raw xanthan yield, average molecular weight of the polymer and residual content of glycerol, total nitrogen and phosphorus. Based on these results, the initial concentration of glycerol as a carbon source in the production medium was suggested. In the applied experimental conditions, high raw xanthan yield (12.15 g/l of good quality (Mw = 2.86•105 g/mol and the lowest amount of residual nutrients (glycerol 2.75 g/l, nitrogen 0.46 g/l and phosphorus 0.67 g/l was achieved in the medium with the initial glycerol content of 20 g/l. The obtained results are the basis for optimization of xanthan production on glycerol containing media in order to increase the product yield and quality.

  2. High hydrogen production from glycerol or glucose by electrohydrogenesis using microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.

    2009-07-01

    The use of glycerol for hydrogen gas production was examined via electrohydrogenesis using microbial electrolysis cells (MECs). A hydrogen yield of 3.9 mol-H2/mol was obtained using glycerol, which is higher than that possible by fermentation, at relatively high rates of 2.0 ± 0.4 m3/m3 d (Eap = 0.9 V). Under the same conditions, hydrogen was produced from glucose at a yield of 7.2 mol-H2/mol and a rate of 1.9 ± 0.3 m3/m3 d. Glycerol was completely removed within 6 h, with 56% of the electrons in intermediates (primarily 1,3-propanediol), with the balance converted to current, intracellular storage products or biomass. Glucose was removed within 5 h, but intermediates (mainly propionate) accounted for only 19% of the electrons. Hydrogen was also produced using the glycerol byproduct of biodiesel fuel production at a rate of 0.41 ± 0.1 m3/m3 d. These results demonstrate that electrohydrogenesis is an effective method for producing hydrogen from either pure glycerol or glycerol byproducts of biodiesel fuel production. © 2009 International Association for Hydrogen Energy.

  3. The role of micronutrients and strategies for optimized continual glycerol production from carbon dioxide by Dunaliella tertiolecta.

    Science.gov (United States)

    Chow, Yvonne; Tu, Wang Yung; Wang, David; Ng, Daphne H P; Lee, Yuan Kun

    2015-10-01

    The microalga Dunaliella tertiolecta synthesizes intracellular glycerol as an osmoticum to counteract external osmotic pressure in high saline environments. The species has recently been found to release and accumulate extracellular glycerol, making it a suitable candidate for sustainable industrial glycerol production if a sufficiently high product titre yield can be achieved. While macronutrients such as nitrogen and phosphorus are essential and well understood, this study seeks to understand the influence of the micronutrient profile on glycerol production. The effects of metallic elements calcium, magnesium, manganese, zinc, cobalt, copper, and iron, as well as boron, on glycerol production as well as cell growth were quantified. The relationship between cell density and glycerol productivity was also determined. Statistically, manganese recorded the highest improvement in glycerol production as well as cell growth. Further experiments showed that manganese availability was associated with higher superoxide dismutase formation, thus suggesting that glycerol production is negatively affected by oxidative stress and the manganese bound form of this enzyme is required in order to counteract reactive oxygen species in the cells. A minimum concentration of 8.25 × 10(-5)  g L(-1) manganese was sufficient to overcome this problem and achieve 10 g L(-1) extracellular glycerol, compared to 4 g L(-1) without the addition of manganese. Unlike cell growth, extracellular glycerol production was found to be negatively affected by the amount of calcium present in the normal growth medium, most likely due to the lower cell permeability at high calcium concentrations. The inhibitory effects of iron also affected extracellular glycerol production more significantly than cell growth and several antagonistic interaction effects between various micronutrients were observed. This study indicates how the optimization of these small amounts of nutrients in a two

  4. The geometry and wetting of capillary folding

    CERN Document Server

    Péraud, Jean-Philippe

    2014-01-01

    Capillary forces are involved in a variety of natural phenomena, ranging from droplet breakup to the physics of clouds. The forces from surface tension can also be exploited in industrial application provided the length scales involved are small enough. Recent experimental investigations showed how to take advantage of capillarity to fold planar structures into three-dimensional configurations by selectively melting polymeric hinges joining otherwise rigid shapes. In this paper we use theoretical calculations to quantify the role of geometry and fluid wetting on the final folded state. Considering folding in two and three dimensions, studying both hydrophilic and hydrophobic situations with possible contact angle hysteresis, and addressing the shapes to be folded to be successively infinite, finite, curved, kinked, elastic, we are able to derive an overview of the geometrical parameter space available for capillary folding.

  5. Capillary flow through heat-pipe wicks

    Science.gov (United States)

    Eninger, J. E.

    1975-01-01

    Theoretical expressions are obtained for the capillary-pressure limit and permeability of a fibrous wick in terms of the porosity and fiber diameter. Hysteresis in capillary pressure is included through the introduction of an empirical hysteresis constant. A partial-saturation model based on the statistical distribution of local porosity requires an additional empirical constant, the standard deviation. The theory is compared to results of a beta-ray absorption experiment that measured the liquid content of a partially saturated wick and to results of permeability measurements on partially and fully saturated wicks. A simple wick-weighing experiment is described that yields values for the empirical hysteresis constant and the standard deviation. Theoretical results are used to design an optimum wick.

  6. Capillary Electrophoresis in Food and Foodomics.

    Science.gov (United States)

    Ibáñez, Clara; Acunha, Tanize; Valdés, Alberto; García-Cañas, Virginia; Cifuentes, Alejandro; Simó, Carolina

    2016-01-01

    Quality and safety assessment as well as the evaluation of other nutritional and functional properties of foods imply the use of robust, efficient, sensitive, and cost-effective analytical methodologies. Among analytical technologies used in the fields of food analysis and foodomics, capillary electrophoresis (CE) has generated great interest for the analyses of a large number of compounds due to its high separation efficiency, extremely small sample and reagent requirements, and rapid analysis. The introductory section of this chapter provides an overview of the recent applications of capillary electrophoresis (CE) in food analysis and foodomics. Relevant reviews and research articles on these topics are tabulated including papers published in the period 2011-2014. In addition, to illustrate the great capabilities of CE in foodomics the chapter describes the main experimental points to be taken into consideration for a metabolomic study of the antiproliferative effect of carnosic acid (a natural diterpene found in rosemary) against HT-29 human colon cancer cells. PMID:27645749

  7. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    Science.gov (United States)

    Ghosal, Sandip

    2006-01-01

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

  8. Capillary solitons on a levitated medium.

    Science.gov (United States)

    Perrard, S; Deike, L; Duchêne, C; Pham, C-T

    2015-07-01

    A water cylinder deposited on a heated channel levitates on its own generated vapor film owing to the Leidenfrost effect. This experimental setup permits the study of the one-dimensional propagation of surface waves in a free-to-move liquid system. We report the observation of gravity-capillary waves under a dramatic reduction of gravity (up to a factor 30), leading to capillary waves at the centimeter scale. The generated nonlinear structures propagate without deformation and undergo mutual collisions and reflections at the boundaries of the domain. They are identified as Korteweg-de Vries solitons with negative amplitude and subsonic velocity. The typical width and amplitude-dependent velocities are in excellent agreement with theoretical predictions based on a generalized Korteweg-de Vries equation adapted to any substrate geometry. When multiple solitons are present, they interact and form a soliton turbulencelike spectrum. PMID:26274114

  9. Capillary Hemangioma of the Fallopian Tube.

    Science.gov (United States)

    Katiyar, Richa; Patne, Shashikant C U; Bharti, Shreekant; Jain, Madhu

    2016-04-01

    Neoplastic lesions of the fallopian tube are rarely seen by surgical pathologists. Haemangioma of the fallopian tube is an extremely rare benign neoplasm. A 30-year-old lady with polymenorrhea and dysmenorrhea underwent hysterectomy and bilateral salpingo-oophorectomy. Her left fallopian tube showed a 2mm sized solid nodule in the wall. Histopathological examination revealed a well-defined vascular lesion in the left fallopian tube, consistent with capillary haemangioma. The vascular endothelium was highlighted by CD34 immunostaining. Our literature review has identified 10 cases of cavernous haemangioma of the fallopian tube. To the best of our knowledge, we report the first ever case of capillary haemangioma of the fallopian tube. This is also the smallest detected haemangioma in the fallopian tube. PMID:27190899

  10. Modeling Microscopic Chemical Sensors in Capillaries

    CERN Document Server

    Hogg, Tad

    2008-01-01

    Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell shapes. The models evaluate two sensing scenarios: robots moving with the cells past a chemical source on the vessel wall, and robots attached to the wall for longer-term chemical monitoring. Using axial symmetric geometry with realistic flow speeds and diffusion coefficients, we compare detection performance with a simpler model that does not include the cells. The average chemical absorption is quantitatively similar in both models, indicating the simpler model is an adequate design guide to sensor performance in capillaries. However, determining the variation in forces and absorption as cells...

  11. Metal Ions Analysis with Capillary Zone Electrophoresis.

    Science.gov (United States)

    Malik, Ashok Kumar; Aulakh, Jatinder Singh; Kaur, Varinder

    2016-01-01

    Capillary electrophoresis has recently attracted considerable attention as a promising analytical technique for metal ion separations. Significant advances that open new application areas for capillary electrophoresis in the analysis of metal species occurred based on various auxiliary separation principles. These are mainly due to complexation, ion pairing, solvation, and micellization interactions between metal analytes and electrolyte additives, which alter the separation selectivity in a broad range. Likewise, many separation studies for metal ions have been concentrated on the use of preelectrophoresis derivatization methodology. Approaches suitable for manipulation of selectivity for different metal species including metal cations, metal complexes, metal oxoanions, and organometallic compounds, are discussed, with special attention paid to the related electrophoretic system variables using illustrative examples. PMID:27645740

  12. Chemical Power for Microscopic Robots in Capillaries

    CERN Document Server

    Hogg, Tad

    2009-01-01

    The power available to microscopic robots (nanorobots) that oxidize bloodstream glucose while aggregated in circumferential rings on capillary walls is evaluated with a numerical model using axial symmetry and time-averaged release of oxygen from passing red blood cells. Robots about one micron in size can produce up to several tens of picowatts, in steady-state, if they fully use oxygen reaching their surface from the blood plasma. Robots with pumps and tanks for onboard oxygen storage could collect oxygen to support burst power demands two to three orders of magnitude larger. We evaluate effects of oxygen depletion and local heating on surrounding tissue. These results give the power constraints when robots rely entirely on ambient available oxygen and identify aspects of the robot design significantly affecting available power. More generally, our numerical model provides an approach to evaluating robot design choices for nanomedicine treatments in and near capillaries.

  13. Electrical resistance of muscle capillary endothelium.

    OpenAIRE

    Olesen, S P; Crone, C

    1983-01-01

    A recently developed technique for in vivo determination of the electrical resistance of vascular endothelium in microvessels was applied to the vessels in a thin frog muscle, m. cutaneus pectoris. The technique consists of injection of current via a glass micropipette into a capillary and measurement of the resulting intra- and extravascular potential profiles with another micropipette placed at various distances from the current source. The theory of Peskoff and Eisenberg (1974) was used to...

  14. Separation of Peptides by Pressurized Capillary Electrochromatography

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel gradient pressurized capillary electrochromatography (pCEC) instrument wasdeveloped to separate peptides. Two gradient elution modes, hydrophobic and hydrophilicinteraction mode in pCEC, were performed on this instrument. Baseline separation of sixpeptides was obtained on two gradient modes with C18 column and strong cationic exchangecolumn respectively. The effects of mixer volume and total flow rate of pumps on resolutionwere also discussed.

  15. Capillary Electrophoresis in the Presence of Fosfomycin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Fosfomyein, a sodim salt of cis-(3-methyloxiranyl) phosphonic acid, was used as electrolyte in binary methanol-water media for capillary electrophoresis. The variety of electroosmotic flow with pH*,methanol concentration and ionic strength was investigated. The migration behavior of nine bases was examined under various conditions, and the separation of thymine, cytosine, 5-flurouracil, 4,6-diamino-pyrimidine, purine was accomplished.

  16. Subsidence and capillary effects in chalks

    OpenAIRE

    Delage, Pierre; Schroeder, Christian; Cui, Yu-Jun

    1996-01-01

    Based on the concepts of the mechanics of unsaturated soils where capillary phenomena arise between the wetting fluid (water) and the non-wetting one (air), the subsidence of chalks containing oil (non-wetting fluid) during water injection (wetting fluid) is analysed. It is shown that the collapse phenomenon of unsaturated soils under wetting provides a physical explanation and a satisfactory prediction of the order of magnitude of the subsidence of the chalk. The use of a well established co...

  17. Familial Pulmonary Capillary Hemangiomatosis Early in Life

    OpenAIRE

    Speer, Christian P.; Mark, Eugene J.; Johannes Wirbelauer; Alexander Marx; Helge Hebestreit

    2011-01-01

    Background. Pulmonary capillary hemangiomatosis (PCH) is a rare disease, especially in infancy. Four infants have been reported up to the age of 12 months. So far, no familial patients are observed at this age. Patients. We report three siblings, two female newborns and a foetus of 15-week gestation of unrelated, healthy parents suffering from histologically proven PCH. The first girl presented with increased O2 requirements shortly after birth and patent ductus arteriosus (PDA). She subseque...

  18. Spatial reconstruction of facial skin capillaries

    Directory of Open Access Journals (Sweden)

    Makarchuk O.I.

    2010-01-01

    Full Text Available To define structural and functional changes of skin capillaries in women of different age groups in this work intraoperational biopsy material of skin of 205 women at the age from 19 to 75 years, that was taken during standard surgery instrumentations for different defects of face and neck skin correction, was investigated. Skin material of cheek face region, temple region of head and anterior neck region was morphologically processed. To define parameters of dermal capillars and spatial reconstruction of intrapapillary capillary loops, serial sections was investigated with the help of morphometry. It was determined, that microcirculation age changes include structural disorders of intrapapillary capillary loops. Essential struc-tural and functional changes observed in skin of cheek region in women of 33-40 years and in temple region of head and anterior neck region in women of 41-50 years. It is typical at the patients with nicotinic dependence, ischemic heart disease, hypertonic disease, a diabetes, and also adiposity of a different degree essential infringement of microvessels bed structure of a skin that gives the basis for allocation of the given contingent of patients as group high intraoperative and postoperative risk at carrying out of operative interventions for correction of face skin involutive changes.

  19. Drinking in Space: The Capillary Beverage Experiment

    Science.gov (United States)

    Wollman, Andrew; Weislogel, Mark; Jenson, Ryan; Graf, John; Pettit, Donald; Kelly, Scott; Lindgren, Kjell; Yui, Kimiya

    2015-11-01

    A selection from as many as 50 different drinks including coffees, teas, and fruit smoothies are consumed daily by astronauts aboard the International Space Station. For practical reasons, the drinks are generally sipped through straws inserted in sealed bags. We present the performance of a special cup designed to allow the drinking operation in much the same manner as on earth, only with the role of gravity replaced by the combined effects of surface tension, wetting, and special container geometry. One can finally `smell the coffee.' Six so-called Space Cups are currently in orbit as part of the Capillary Beverage Experiment which aims to demonstrate specific passive control of poorly wetting aqueous capillary systems through a fun mealtime activity. The mathematical fluid mechanical design process with full numerical simulations is presented alongside experimental results acquired using a drop tower and low-g aircraft before complete characterization aboard the Space Station. Astronaut commentary is both humorous and informative, but the insightful experimental results of the potable space experiment testify to the prospects of new no-moving-parts capillary solutions for certain water-based life support operations aboard spacecraft.

  20. Highly conductive, printable pastes from capillary suspensions

    Science.gov (United States)

    Schneider, Monica; Koos, Erin; Willenbacher, Norbert

    2016-08-01

    We have used the capillary suspension phenomenon to design conductive pastes for printed electronic applications, such as front side metallization of solar cells, without non-volatile, organic additives that often deteriorate electrical properties. Adding a small amount of a second, immiscible fluid to a suspension creates a network of liquid bridges between the particles. This capillary force-controlled microstructure allows for tuning the flow behavior in a wide range. Yield stress and low-shear viscosity can be adjusted such that long-term stability is provided by inhibiting sedimentation, and, even more importantly, narrow line widths and high aspect ratios are accessible. These ternary mixtures, called capillary suspensions, exhibit a strong degree of shear thinning that allows for conventional coating or printing equipment to be used. Finally, the secondary fluid, beneficial for stability and processing of the wet paste, completely evaporates during drying and sintering. Thus, we obtained high purity silver and nickel layers with a conductivity two times greater than could be obtained with state-of-the-art, commercial materials. This revolutionary concept can be easily applied to other systems using inorganic or even organic conductive particles and represents a fundamental paradigm change to the formulation of pastes for printed electronics.

  1. Microcirculatory dysfunction and tissue oxygenation in critical illness.

    Science.gov (United States)

    Østergaard, L; Granfeldt, A; Secher, N; Tietze, A; Iversen, N K; Jensen, M S; Andersen, K K; Nagenthiraja, K; Gutiérrez-Lizardi, P; Mouridsen, K; Jespersen, S N; Tønnesen, E K

    2015-11-01

    Severe sepsis is defined by organ failure, often of the kidneys, heart, and brain. It has been proposed that inadequate delivery of oxygen, or insufficient extraction of oxygen in tissue, may explain organ failure. Despite adequate maintenance of systemic oxygen delivery in septic patients, their morbidity and mortality remain high. The assumption that tissue oxygenation can be preserved by maintaining its blood supply follows from physiological models that only apply to tissue with uniformly perfused capillaries. In sepsis, the microcirculation is profoundly disturbed, and the blood supply of individual organs may therefore no longer reflect their access to oxygen. We review how capillary flow patterns affect oxygen extraction efficacy in tissue, and how the regulation of tissue blood flow must be adjusted to meet the metabolic needs of the tissue as capillary flows become disturbed as observed in critical illness. Using the brain, heart, and kidney as examples, we discuss whether disturbed capillary flow patterns might explain the apparent mismatch between organ blood flow and organ function in sepsis. Finally, we discuss diagnostic means of detecting capillary flow disturbance in animal models and in critically ill patients, and address therapeutic strategies that might improve tissue oxygenation by modifying capillary flow patterns. PMID:26149711

  2. Experimental study of the supercritical water reforming of glycerol without the addition of a catalyst

    International Nuclear Information System (INIS)

    Hydrogen production from the supercritical water reforming of glycerol was studied in a tubular reactor without adding a catalyst. Experiments were carried out at a pressure of 240 bar, temperatures of 750–850 °C, and glycerol feed concentrations of 5–30 wt.%. Likewise, the residence time was changed from 12 to 160 s, by handling the feed flow-rate. The dry gas is mainly consisted of H2, CO2, CO, CH4. In addition, small concentrations of glycerol were measured in the liquid phase analysis, but barely traces of others like glycolaldehyde, glyceraldehyde, dihydroxyacetone and lactic acid were detected. Thus, two probable reaction pathways are discussed, which makes it possible to explain the experimental results by using a method applicable to other similar processes. The results showed that the glycerol conversion was almost complete, except at the highest glycerol feed concentration, in which the conversion was of 88%. Hydrogen yields from 2 to 4 mol H2/mol glycerol were obtained at high and low glycerol feed concentrations, respectively, when operating at high temperature and residence time. Besides, it was verified the catalytic effect of the reactor material (Inconel 625) from the trend of the gas product yields with time and the structured carbon nanotubes encountered. The catalytic activity of the reactor material was decreasing to reach a steady state after a few tens of operating hours. This study illustrates that the reforming of glycerol using supercritical water without added catalyst is feasible to achieve a high-yield hydrogen production, and it encourages to continue the research line, to obtain a process economically interesting. - Highlights: • Glycerol reforming using supercritical water without adding a heterogenous catalyst is feasible. • The use of a glycerol concentration as high as 30 wt.% produces a gas with high hydrogen yield. • The effect of operating variables on the process performance and approach to chemical equilibrium was

  3. Blood-retinal barrier glycerol permeability in diabetic macular edema and healthy eyes: estimations from macular volume changes after peroral glycerol

    DEFF Research Database (Denmark)

    Thornit, Dorte Nellemann; Vinten, Carl Martin; Sander, Birgit;

    2010-01-01

    PURPOSE: To compare the changes in macular volume (MV) between healthy subjects and patients with diabetic macular edema (DME) after an osmotic load and to determine the glycerol permeability (P(gly)) of the blood-retinal barrier (BRB). METHODS: In this unmasked study, 13 patients with DME and 5...

  4. On the role of the activation procedure of supported hydrotalcites for base catalyzed reactions: Glycerol to glycerol carbonate and self-condensation of acetone

    NARCIS (Netherlands)

    Alvarez, M.G.; Frey, A.M.; Bitter, J.H.; Segarra, A.M.; Jong, de K.P.; Medina, F.

    2013-01-01

    Bulk and carbon nanofiber supported MgAl hydrotalcites have been investigated as solid base catalysts for the synthesis of glycerol carbonate and dicarbonate and for the self-condensation of acetone. The supported materials exhibited a 300 times higher activity compared to bulk activated hydrotalcit

  5. EFFECT OF CORN STEEP LIQUOR CONCENTRATION ON GLYCEROL PRODUCTION AND KINETIC ANALYSIS OF GLYCEROL FERMENTATION%玉米浆浓度对甘油发酵的影响及动力学

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In batch cultures of Candida krusei, the effect of corn steep liquor (CSL) concentration was investigated. The result showed that glycerol yield was greatly affected by CSL concentration. Higher glycerol yield was attained when the initial CSL concentration in the medium was 9 g.L-1. The fermentation kinetics were studied and the parameters for cell growth, maintenance, and glycerol production were obtained. Material balance revealed by product formation during the growth phase and suggested a fed-batch culture strategy.

  6. Thinking Critically about Critical Thinking

    Science.gov (United States)

    Mulnix, Jennifer Wilson

    2012-01-01

    As a philosophy professor, one of my central goals is to teach students to think critically. However, one difficulty with determining whether critical thinking can be taught, or even measured, is that there is widespread disagreement over what critical thinking actually is. Here, I reflect on several conceptions of critical thinking, subjecting…

  7. A covalent modified hydrophilic capillary for enhanced capillary electrophoresis of biopolymers

    Institute of Scientific and Technical Information of China (English)

    Lian Guo Shan; Xue Yu; Yin Mao Wei; Xiao Hui Zheng; Jian Bin Zheng

    2009-01-01

    δ-Gluconolactone was covalently coupled to aminopropyl derivatized capillary,which created hydrophilic brushes on the inner wall of the capillary.The coated capillary was shown to generate a stable electroosmotic flow(EOF)in the investigated pH range of 2.0-9.0 and to suppress effectively the adsorption of proteins.And it enabled separation of some biopolymer mixtures including basic proteins,DNA and tryptic digested bovine serum albumin(BSA)within 15 min with efficiencies up to 450,000 plates/m.The intra-and inter-day reproducibility of the coating referring to the retention times of proteins were satisfactory with mean relative standard deviations(R.S.D.)of 0.8 and 1.7%,respectively.

  8. In-capillary derivatization and capillary electrophoresis separation of amino acid neurotransmitters from brain microdialysis samples.

    Science.gov (United States)

    Denoroy, Luc; Parrot, Sandrine; Renaud, Louis; Renaud, Bernard; Zimmer, Luc

    2008-09-26

    A new in-capillary derivatization method with naphtalene-2,3-dicarboxyaldehyde (NDA)/CN(-) has been developed for capillary electrophoresis with laser-induced fluorescence detection of brain microdialysate amino acids. Samples are sandwiched between two plugs of reagent mixture at the capillary inlet and subsequently separated. Highest derivatization yields are obtained by using a reagent to sample plug length ratio equal to 4, performing a first electrophoretic mixing followed by a zero potential amplification step before applying the separation voltage and using a NaCN to NDA concentration ratio equal to 1. This new single-step methodology allows the analysis of amino acid neurotransmitters in rat brain microdialysis samples.

  9. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    Science.gov (United States)

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol. PMID:26112364

  10. Structural Characterizations of Glycerol Kinase: Unraveling Phosphorylation-Induced Long-Range Activation

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Joanne I.; Kettering, Regina; Saxl, Ruth; Bourand, Alexa; Darbon, Emmanuelle; Joly, Nathalie; Briozzo, Pierre; Deutscher, Josef; (Pitt); (CNRS-CRMD)

    2009-09-11

    Glycerol metabolism provides a central link between sugar and fatty acid catabolism. In most bacteria, glycerol kinase plays a crucial role in regulating channel/facilitator-dependent uptake of glycerol into the cell. In the firmicute Enterococcus casseliflavus, this enzyme's activity is enhanced by phosphorylation of the histidine residue (His232) located in its activation loop, approximately 25 A from its catalytic cleft. We reported earlier that some mutations of His232 altered enzyme activities; we present here the crystal structures of these mutant GlpK enzymes. The structure of a mutant enzyme with enhanced enzymatic activity, His232Arg, reveals that residues at the catalytic cleft are more optimally aligned to bind ATP and mediate phosphoryl transfer. Specifically, the position of Arg18 in His232Arg shifts by approximately 1 A when compared to its position in wild-type (WT), His232Ala, and His232Glu enzymes. This new conformation of Arg18 is more optimally positioned at the presumed gamma-phosphate location of ATP, close to the glycerol substrate. In addition to structural changes exhibited at the active site, the conformational stability of the activation loop is decreased, as reflected by an approximately 35% increase in B factors ('thermal factors') in a mutant enzyme displaying diminished activity, His232Glu. Correlating conformational changes to alteration of enzymatic activities in the mutant enzymes identifies distinct localized regions that can have profound effects on intramolecular signal transduction. Alterations in pairwise interactions across the dimer interface can communicate phosphorylation states over 25 A from the activation loop to the catalytic cleft, positioning Arg18 to form favorable interactions at the beta,gamma-bridging position with ATP. This would offset loss of the hydrogen bonds at the gamma-phosphate of ATP during phosphoryl transfer to glycerol, suggesting that appropriate alignment of the second substrate of

  11. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    Science.gov (United States)

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol.

  12. An axial approach to detection in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.

    1993-05-01

    Our approach involves on-axis illumination of the compounds inside the capillary detection region and is applied to absorbance and fluorescence detection. Absorbance measurements were made by focussing an incident laser beam into one capillary end; by using signals collected over the entire length of analyte band, this enhances the analytical path length of conventional absorbance detection 60x. This instrument offers a 15x improvement in detection limits. Three fluorescence detection experiments are discussed, all of which involve insertion of an optical fiber into capillary. The first uses a high refractive index liquid phase to obtain total internal reflectance along capillary axis, this reducing light scatter. The second uses a charge-coupled device camera for simultaneous imaging of a capillary array (this may be useful in genome sequencing, etc.). The third is a study of fluid motion inside the capillary under pressure-driven and electroosmotic flow. The thesis is divided into four parts. Figs, tabs.

  13. Occurrence and abundance of 6-methyl branched glycerol dialkyl glycerol tetraethers in soils: Implications for palaeoclimate reconstruction

    Science.gov (United States)

    De Jonge, Cindy; Hopmans, Ellen C.; Zell, Claudia I.; Kim, Jung-Hyun; Schouten, Stefan; Sinninghe Damsté, Jaap S.

    2014-09-01

    The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with the soil pH and the mean annual air temperature (MAT). This has been used to perform palaeoclimate reconstructions based on brGDGTs recovered from palaeosoils, freshwater, and marine sedimentary archives. Recently described 6-methyl brGDGTs were shown to co-elute with the 5-methyl brGDGTs that are used to calculate the CBT and MBT‧ indices used as palaeoclimate proxies. The impact of these 6-methyl brGDGTs on the established palaeoclimate proxies is unknown and will depend on their abundance in soils. Using improved chromatography, we quantified the fractional abundance of 6-methyl brGDGTs in globally distributed soils and show that they are abundant components, comprising on average 24% of the total amount of brGDGTs. All penta- and hexa-methylated brGDGTs (i.e. with zero to two cyclopentane moieties) were shown to comprise both 5- and 6-methyl isomers. The fractional abundances of the six 6-methyl brGDGTs correlate positively with each other, suggesting a common biological source in most soils, and correlate strongly with soil pH. The presence of the 6-methyl brGDGTs introduced scatter in the original MBT‧/CBT-MAT calibration and caused a dependence on soil pH of the MBT‧. Exclusion of the 6-methyl brGDGTs from the MBT‧, i.e. the newly defined MBT‧5ME, shows that it is no longer related to soil pH. The correlation with MAT is improved, reducing the residual mean error (RMSE) from 6.2 to 4.8 °C. Also, the correlation of the CBT after the exclusion of the 6-methyl brGDGTs (defined as CBT5ME) with soil pH slightly improved. Furthermore, the separate quantification of the 6-methyl brGDGTs allows the definition of new indices. The CBT‧, which comprises the 6-methyl brGDGTs, is a substantially improved alternative to the CBT5ME, reducing the RMSE from 0.8 to 0.5 pH units. Also, the accuracy of MAT reconstructions can be improved using a

  14. Critical Care

    Science.gov (United States)

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, ... attention by a team of specially-trained health care providers. Critical care usually takes place in an ...

  15. Effect of impurities in biodiesel-derived waste glycerol on the performance and feasibility of biotechnological processes

    Energy Technology Data Exchange (ETDEWEB)

    Chatzifragkou, Afroditi; Papanikolaou, Seraphim [Agricultural Univ. of Athens (Greece). Lab. of Food Microbiology and Biotechnology

    2012-07-15

    The rapid development of biodiesel production technology has led to the generation of tremendous quantities of glycerol wastes, as the main by-product of the process. Stoichiometrically, it has been calculated that for every 100 kg of biodiesel, 10 kg of glycerol are produced. Based on the technology imposed by various biodiesel plants, glycerol wastes may contain numerous kinds of impurities such as methanol, salts, soaps, heavy metals, and residual fatty acids. This fact often renders biodiesel-derived glycerol unprofitable for further purification. Therefore, the utilization of crude glycerol though biotechnological means represents a promising alternative for the effective management of this industrial waste. This review summarizes the effect of various impurities-contaminants that are found in biodiesel-derived crude glycerol upon its conversion by microbial strains in biotechnological processes. Insights are given concerning the technologies that are currently applied in biodiesel production, with emphasis to the impurities that are added in the composition of crude glycerol, through each step of the production process. Moreover, extensive discussion is made in relation with the impact of the nature of impurities upon the performances of prokaryotic and eukaryotic microorganisms, during crude glycerol bioconversions into a variety of high added-value metabolic products. Finally, aspects concerning ways of crude glycerol treatment for the removal of inhibitory contaminants as reported in the literature are given and comprehensively discussed. (orig.)

  16. A low-cost synthesis of biodiesel at room temperature and purification of by-product glycerol for reuse

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Yogesh C.; Singh, Bhaskar; Agrawal, Shweta [Banaras Hindu University, Department of Applied Chemistry, Institute of Technology, Varanasi (India)

    2012-03-15

    Biodiesel has been synthesized from used frying oil at room temperature (35 C) using NaOH and CH{sub 3}ONa as homogeneous catalyst and methanol as reactant. Glycerol has been obtained as a by-product which comprised of impurities such as unreacted methanol, inorganic metals, and traces of triglycerides. The inorganic materials present in glycerol were adsorbed on the surface of activated carbon derived from rice husk. Glycerol is then acidified with 1.2 M H{sub 2}SO{sub 4} to form two layers. The upper layer comprised of free fatty acids, and the bottom layer comprised of a glycerol-rich layer. The bottom layer was decanted and neutralized with an aqueous solution of 10 M NaOH and heated at 110 C for 2.5 h to remove the residual water in the glycerol. Further extraction of glycerol with ethanol gives glycerol of high purity. For removal of ethanol from the glycerol, the solution was heated up to 80 C for 30 min. The purity of glycerol was verified by analysis on {sup 13}C-NMR. The upper free fatty acid layer is confirmed with the help of the treatment of this layer with base solution (NaOH) to give soap. Formation of soap is confirmed with the help of Fourier transform infrared spectroscopy. (orig.)

  17. Capillary remodeling in bleomycin-induced pulmonary fibrosis.

    OpenAIRE

    Schraufnagel, D. E.; Mehta, D.; Harshbarger, R.; Treviranus, K.; Wang, N. S.

    1986-01-01

    Lung fibrosis is a process in which collagen is laid down and the delicate capillary-alveolar relationship is disturbed. The architectural changes which occur in the capillaries, a main element of the oxygen transferring unit, are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in rats by intratracheal instillation...

  18. Nicked-sleeve interface for two-dimensional capillary electrophoresis

    OpenAIRE

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

    2013-01-01

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

  19. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    Wei Chang; Tusyo-shi Komazu

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

  20. Acute metabolic responses of postpartal dairy cows to subcutaneous glucagon injections, oral glycerol, or both.

    Science.gov (United States)

    Osman, M A; Allen, P S; Mehyar, N A; Bobe, G; Coetzee, J F; Koehler, K J; Beitz, D C

    2008-09-01

    This study examined the effects of multiple subcutaneous glucagon injections with or without co-administration of oral glycerol on energy status-related blood metabolites and hormones of Holstein dairy cows in the first 2 wk postpartum. Twenty multiparous cows were fed a dry cow ration supplemented with 6 kg of cracked corn during the dry period to increase the likelihood of developing postpartal fatty liver syndrome. Cows with a body condition score of >or=3.5 points (1- to 5-point scale) were assigned randomly to 1 of 4 treatment groups: saline, glucagon, glycerol, or glucagon plus glycerol. Following treatment, serial blood samples were collected over an 8-h period to determine the effects of glucagon and glycerol on blood metabolites and hormones. Treatment effects were determined by comparing the concentrations of metabolites and hormones during the first 4-h period and the entire 8-h period after treatment administration (time 0) with the concentration of the same compounds at time 0 on d 1, 7, and 13 postpartum. Administration of glucagon alone increased concentrations of plasma glucagon and insulin on d 1, 7, and 13 and increased plasma glucose and decreased plasma nonesterified fatty acids (NEFA) on d 7 and 13 postpartum relative to the saline group. Administration of glycerol alone increased plasma glucose on d 7 and plasma triacylglycerols on d 1 postpartum. Glycerol administration also decreased plasma glucagon and NEFA on d 1, 7, and 13 and plasma beta-hydroxybutyrate (BHBA) on d 1 postpartum relative to the saline group. Administration of glucagon plus glycerol increased and sustained concentrations of plasma glucagon, glucose, and insulin on d 1, 7, and 13 and decreased plasma NEFA on d 1, 7, and 13 and BHBA on d 1 and 7. Early postpartal treatment of dairy cows with glucagon plus glycerol increased plasma glucose and insulin, decreased plasma NEFA and BHBA, and increased secretion of liver NEFA as plasma triacylglycerols. This suggests that glucagon

  1. High Performance Wafer-Based Capillary Electrochromatography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II research comprises designing, constructing, and testing a chip-based capillary electrochromatography (CEC) prototype for separation and analysis of...

  2. A Prediction Model of the Capillary Pressure J-Function

    Science.gov (United States)

    Xu, W. S.; Luo, P. Y.; Sun, L.; Lin, N.

    2016-01-01

    The capillary pressure J-function is a dimensionless measure of the capillary pressure of a fluid in a porous medium. The function was derived based on a capillary bundle model. However, the dependence of the J-function on the saturation Sw is not well understood. A prediction model for it is presented based on capillary pressure model, and the J-function prediction model is a power function instead of an exponential or polynomial function. Relative permeability is calculated with the J-function prediction model, resulting in an easier calculation and results that are more representative. PMID:27603701

  3. Novel Micro-Capillary Electrochromatography for Mars Organic Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a powerful new technology - next generation Micro-Capillary Electrochromatography ? a high performance and low power...

  4. Capillary-Condenser-Pumped Heat-Transfer Loop

    Science.gov (United States)

    Silverstein, Calvin C.

    1989-01-01

    Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

  5. Capillary Micro-Flow Through a Fiber Bundle(Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; WANG Ji-hui; TAN Hua; GAO Guo-qiang

    2004-01-01

    The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short- time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.

  6. Novel Micro-Capillary Electrochromatography for Mars Organic Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a powerful new technology - next generation Micro-Capillary Electrochromatography - a high performance and low power...

  7. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil;

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate...... blood flow, capillaries dilate before arterioles and are estimated to produce 84% of the blood flow increase. In pathology, ischaemia evokes capillary constriction by pericytes. We show that this is followed by pericyte death in rigor, which may irreversibly constrict capillaries and damage the blood-brain...

  8. Glycerol-enriched heterogeneous catalyst for biodiesel production from soybean oil and waste frying oil

    International Nuclear Information System (INIS)

    Highlights: • An alkali metal-glyceroxide heterogeneous catalyst was improved aiming biodiesel production. • Optimized reaction conditions were comparable to homogeneous catalysis. • High yield and good product quality was obtained using refined and waste oil. • The catalyst could be reused four times and prepared using methanol or ethanol. - Abstract: In the present work, biodiesel production using a glycerol enriched heterogeneous catalyst was studied. For that purpose, the catalyst performance at different glycerol concentrations and reaction conditions (under ambient atmosphere) was evaluated and two triglyceride sources were used. The most active catalyst was produced using CaO, glycerol and methanol at a mass ratio of 1:1.6:13.4, respectively. By performing the transesterification reaction under ambient atmosphere during 2 h at 333 K, using 0.4 wt.% of catalyst and 7:1 methanol to oil molar ratio, a good quality product was obtained (EN 14214) using both soybean oil and waste frying oil. The catalyst could be re-used during four cycles and could also be prepared by using ethanol instead of methanol (with differences <4% on product conversion). The glycerol by-product, being rich in calcium soaps, might additionally be used for the enrichment of animal diets. The present process allowed the production of biodiesel from different triglyceride sources using a very active heterogeneous catalyst at competitive reaction conditions compared to the homogeneous process and also enabled a two-way recycling of the glycerol by-product

  9. Pharmacological investigations of Punica granatum in glycerol-induced acute renal failure in rats

    Directory of Open Access Journals (Sweden)

    Amrit Pal Singh

    2011-01-01

    Full Text Available Objective : The present study was designed to investigate the ameliorative potential and possible mechanism of hydroalcoholic extract of flowers of P. granatum in glycerol-induced acute renal failure (ARF in rats. Materials and Methods : The rats were subjected to rhabdomyolytic ARF by single intramuscular injection of hypertonic glycerol (50% v/v; 8 ml/kg and the animals were sacrificed after 24 hours of glycerol injection. The plasma creatinine, blood urea nitrogen, creatinine clearance, and histopathological studies were performed to assess the degree of renal injury. Results : Pretreatment with hydroalcoholic extract of flowers of P. granatum (125 and 250 mg/kg p.o. twice daily for 3 days significantly attenuated hypertonic glycerol-induced renal dysfunction in a dose-dependent manner. BADGE (Bisphenol-A-diglycidyl ether (30 mg/kg, a peroxisome proliferator-activated receptor (PPAR-γ antagonist, and N(omega-nitro-l-arginine-methyl ester (L-NAME (10, 20, and 40 mg/kg, nitric oxide synthase inhibitor, were employed to explore the mechanism of renoprotective effects of Punica granatum. Administration of BADGE (30 mg/kg and L-NAME (40 mg/kg abolished the beneficial effects of P. granatum in glycerol-induced renal dysfunction. Conclusion : Hydroalcoholic extract of flowers of P. granatum has ameliorative potential in attenuating myoglobinuric renal failure and its renoprotective effects involve activation of PPAR-γ and nitric oxide-dependent signaling pathway.

  10. Synergetic hydrothermal co-liquefaction of crude glycerol and aspen wood

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Jasiunas, Lukas; Casamassima, Luca;

    2015-01-01

    Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co-processing ......Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co......-processing aspen wood and neat glycerol led to a significant reduction in the char yield, and glycerol is hypothesized to act as a radical scavenger, alleviating re-polymerization of especially lignin-derived fragments. In the temperature range of 380–420 °C, it was found that biocrude and char yield, and biocrude...... quality were all invariant to the reaction temperature. By increasing the crude glycerol to aspen wood mass ratio from 0:1 to 3:1, char yield was decreased from 18.3% (only aspen wood) to 3.4%. Furthermore, the biocrude quality in terms of the effective hydrogen-to-carbon ratio (H/Ceff) was significantly...

  11. The effect of replacing corn with glycerol on ruminal bacteria in continuous culture fermenters.

    Science.gov (United States)

    AbuGhazaleh, A A; Abo El-Nor, S; Ibrahim, S A

    2011-06-01

    The effects of substituting corn with glycerol on DNA concentration of selected ruminal bacteria were investigated using continuous fermenters. Four continuous culture fermenters were used in a 4 × 4 Latin Square design with four 10 days consecutive periods. Treatment diets (60:40 forage to concentrate) were fed at 45 g/day dry matter (DM) in three equal portions. Glycerol (0.995 g/g glycerol) was used to replace corn in a grain mix at proportions of 0% (T0; control), 15% (T15), 30% (T30) and 45% (T45). On day 10 of each period, samples were collected from each fermenter 3 h after the morning feeding and analysed for volatile fatty acid and bacterial DNA concentration. Glycerol substitution was related to significantly higher butyrate, valerate and isovalerate concentrations. Compared with the T0 diet, acetate concentration was significantly lower with the T30 and T45 diets whilst propionate concentration was higher only with the T45 diet. The DNA concentrations for Butyrivibrio fibrisolvens and Selenomonas ruminantium decreased with the T30 and T45 diets compared with the T0 diet. No differences in the DNA concentrations for Ruminococcus albus and Succinivibrio dextrinosolvens amongst diets were observed. The findings show that substituting 15% of the dietary corn with glycerol had no substantive effects on fermentation processing or ruminal bacteria. Higher substitution levels, however, may adversely affect ruminal bacteria and negatively impact acetate production. PMID:20880288

  12. Gelatinization and retrogradation phenomena in starch/montmorillonite nanocomposites plasticized with different glycerol/water ratios.

    Science.gov (United States)

    Lara, Sandra Camila; Salcedo, Felipe

    2016-10-20

    This study aims to gain insights into the intermolecular interactions present in thermoplastic starch (TPS)/montmorillonite (MMT) nanocomposites prepared using water and/or glycerol as plasticizers. Specifically, the impact of using different glycerol/water proportions on the nature of gelatinization and retrogradation processes is studied. Nanocomposites were characterized by rheometry, scanning electron microscopy (SEM) and X-rays diffraction (XRD). It is shown that clay tactoids preferentially interact with glycerol molecules rather than starch macromolecules. Consequently, the effects of MMT incorporation strongly depend on the glycerol/water ratio; when a ratio of 0.5 is used minor variations were observed on the starch gelatinization process-although stronger clays-starch interactions were evident-whereas at higher ratios the addition of clays significantly increased the gelatinization temperature, up to values over 100°C. In the gelatinization process of starch in TPS samples having only glycerol as a plasticizer, the leaching of amylose and the melting of amylopectin crystalline domains seem to occur simultaneously. This different gelatinization mechanism produces a TPS having a substantially different morphology, which exhibited reduced retrogradation characteristics. PMID:27474559

  13. Optimization of 1,3-dihydroxyacetone production from crude glycerol by immobilized Gluconobacter oxydans MTCC 904.

    Science.gov (United States)

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    This study has addressed the matter of optimization of production of the value added product, dihydroxyacetone, from crude glycerol using immobilized cells of Gluconobacter oxydans. Statistical optimization of the fermentation medium revealed MgSO4·7H2O, (NH4)2SO4 and KH2PO4 as the significant components, in addition to small concentration of yeast extract. As per previous literature, these components augment the activity of glycerol dehydrogenase enzyme in metabolism and provide assimilable nitrogen and sulfur source for cell growth. Yeast extract not only provides essential growth factors, but also accelerates production of alcohol dehydrogenase enzyme due to amino acids present. The DHA yield from crude glycerol (20g/L) with optimized medium is 14.08g/L, which is just 12% lower than the yield for pure glycerol .This study has thus established that proper optimization of fermentation medium reduces the adverse effect of impurities in crude glycerol on fermentation process and DHA yield. PMID:26873288

  14. Liquid phase conversion of Glycerol to Propanediol over highly active Copper/Magnesia catalysts

    Indian Academy of Sciences (India)

    Satyanarayana Murty Pudi; Abdul Zoeb; Prakash Biswas; Shashi Kumar

    2015-05-01

    In this work, a series of Cu/MgO catalysts with different copper metal loading were prepared by the precipitation-deposition method. Their catalytic behaviour was investigated for glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO). The physico-chemical properties of the catalysts were characterized by various techniques such as BET surface area, X-ray diffraction (XRD), temperature programmed reduction (TPR), NH3-temperature programmed desorption (NH3-TPD) and scanning electron microscopy (SEM) methods. The characterization results showed that the copper metal was well-dispersed over MgO support and a new phase Cu-MgO was also identified from XRD results after calcination. The 25Cu/MgO (Cu:25 wt%) catalyst exhibited the highest glycerol conversion of 88.7% and 1,2-PDO selectivity of 91.7% at 210°C, 4.5MPa of hydrogen pressure after 12 h. The high glycerol conversion was mainly due to the Cu dispersion on MgO support and high acidic strength. Further, the effects of temperature, hydrogen pressure, catalyst loading and glycerol concentration were studied over 25Cu/MgO catalyst for optimization of reaction parameters. Kinetic study over highly active 25Cu/MgO catalyst showed that the reaction followed the pseudo second order rate with respect to glycerol and the apparent activation energy was found to be 28.7 ± 0.8 kcal/mol.

  15. Effect of glycerol on sustained insulin release from PVA hydrogels and its application in diabetes therapy

    Science.gov (United States)

    Cai, Yunpeng; Che, Junyi; Yuan, Minglu; Shi, Xiaohong; Chen, Wei; Yuan, Wei-En

    2016-01-01

    The present study aimed to investigate the effects of glycerol on the physical properties and release of an insulin-loaded polyvinyl alcohol (PVA) hydrogel film. The insulin-loaded hydrogel composite film was produced using the freeze-thawing method, after which the in vitro swelling ratio, transmittance and insulin release, and the in vivo pharmacodynamics, of hydrogels containing various volumes of glycerol were investigated. The results demonstrated that the addition of glycerol reduced the swelling ratio and increased the softness of the PVA hydrogel film. An analysis of insulin release in vitro and of the hypoglycemic effects in rats demonstrated that the PVA hydrogel film had a sustained release of insulin and long-acting effect over 10 days. The results of the present study suggested that, as a hydrophilic plasticizer, glycerol was able to enhance the release of insulin in the early stage of release profile by enhancing the formation of water channels, although the total swelling ratio was decreased. Therefore, the insulin-loaded glycerol/PVA hydrogel film may be a promising sustained-release preparation for the treatment of diabetes.

  16. Glycerol-Induced Membrane Stiffening: The Role of Viscous Fluid Adlayers

    Energy Technology Data Exchange (ETDEWEB)

    Pocivavsek, Luka; Gavrilov, Kseniya; Cao, Kathleen D.; Chi, Eva Y.; Li, Dongxu; Lin, Binhua; Meron, Mati; Majewski, Jaroslaw; Lee, Ka Yee C. (UNM); (UC); (LANL)

    2011-12-09

    Lipid interfaces, ranging from cell membranes to thin surfactant layers that stabilize lung alveoli, are integral to living systems. Such interfaces are often subjected to mechanical forces, and because of their membrane-like geometry, they can easily deform by bending into localized folds. In this work, we explore the role of small molecules (i.e., glycerol) on the mechanical stability of model lung surfactant monolayers. We demonstrate that the presence of glycerol increases local monolayer bending stiffness by orders of magnitude. Our x-ray and neutron reflectivity measurements indicate that water is preferentially depleted, or glycerol is preferentially enriched, at the lipid headgroup/solvent interface, and that this glycerol-enriched layer extends O(10) beneath the monolayer with an adsorption free energy of 2.5 to 4.6 kJ/mol. The dramatic change in membrane bending stiffness in the presence of the sugar adlayer is understood in terms of two models: (1), lipid antiplasticization by glycerol; and (2), a continuum mechanical model of the viscous adlayer.

  17. Glycerol-Induced Membrane Stiffening: The Role of Viscous Fluid Adlayers

    International Nuclear Information System (INIS)

    Lipid interfaces, ranging from cell membranes to thin surfactant layers that stabilize lung alveoli, are integral to living systems. Such interfaces are often subjected to mechanical forces, and because of their membrane-like geometry, they can easily deform by bending into localized folds. In this work, we explore the role of small molecules (i.e., glycerol) on the mechanical stability of model lung surfactant monolayers. We demonstrate that the presence of glycerol increases local monolayer bending stiffness by orders of magnitude. Our x-ray and neutron reflectivity measurements indicate that water is preferentially depleted, or glycerol is preferentially enriched, at the lipid headgroup/solvent interface, and that this glycerol-enriched layer extends O(10) beneath the monolayer with an adsorption free energy of 2.5 to 4.6 kJ/mol. The dramatic change in membrane bending stiffness in the presence of the sugar adlayer is understood in terms of two models: (1), lipid antiplasticization by glycerol; and (2), a continuum mechanical model of the viscous adlayer.

  18. Energy balance of biofuel production from biological conversion of crude glycerol.

    Science.gov (United States)

    Zhang, Xiaolei; Yan, Song; Tyagi, Rajeshwar D; Surampalli, Rao Y; Valéro, Jose R

    2016-04-01

    Crude glycerol, a by-product of biodiesel production, has gained significant attention as a carbon source for biofuel production. This study evaluated the energy balance of biodiesel, hydrogen, biogas, and ethanol production from 3.48 million L of crude glycerol (80% w/v). The conversion efficiency (energy output divided by energy invested) was 1.16, 0.22, 0.27, and 0.40 for the production of biodiesel, hydrogen, biogas, and ethanol respectively. It was found that the use of crude glycerol for biodiesel production was an energy gain process, with a positive energy balance and conversion efficiency of greater than 1. The energy balance revealed a net energy gain of 5226 GJ per 1 million kg biodiesel produced. Production of hydrogen, biogas and ethanol from crude glycerol were energy loss processes. Therefore, the conversion of crude glycerol to lipids and subsequently to biodiesel is suggested to be a better option compared to hydrogen, biogas, or ethanol production with respect to energy balance.

  19. Electroviscous effects in capillary filling of nanochannels

    DEFF Research Database (Denmark)

    Mortensen, Asger; Kristensen, Anders

    2008-01-01

    maximum in the mesoscopic regime where the channel height (or more generally the hydraulic radius) is comparable to the screening length. However, for realistic estimates of central parameters, we find that the electroviscous contribution to the apparent viscosity is at most a 1% effect.......We theoretically examine the widespread hypothesis of an electroviscous origin of the increase in apparent viscosity observed in recent experiments on capillary filling of nanochannels. Including Debye-layer corrections to the hydraulic resistance, we find that the apparent viscosity reaches a...

  20. Capillary-Pumped Heat-Transfer Loop

    Science.gov (United States)

    1989-01-01

    New type of capillary-pumped heat-transfer loop primes itself at startup. Removes substantial quantities of heat like that generated by people and equipment in rooms and vehicles. Creates continuous path for its working fluid; both vapor and liquid move in same direction. Key element in operation of loop is formation of slugs of liquid, condensed from vapor and moved along loop by vapor bubbles before and after it. Both evaporator and condenser contain axial arteries carrying water. Heat entering evaporator from heat source provides energy for transport of fluid and heat. Dimensions in inches.

  1. Capillary Network, Cancer and Kleiber Law

    CERN Document Server

    Dattoli, G; Licciardi, S; Guiot, C; Deisboeck, T S

    2014-01-01

    We develop a heuristic model embedding Kleiber and Murray laws to describe mass growth, metastasis and vascularization in cancer. We analyze the relevant dynamics using different evolution equations (Verhulst, Gompertz and others). Their extension to reaction diffusion equation of the Fisher type is then used to describe the relevant metastatic spreading in space. Regarding this last point, we suggest that cancer diffusion may be regulated by Levy flights mechanisms and discuss the possibility that the associated reaction diffusion equations are of the fractional type, with the fractional coefficient being determined by the fractal nature of the capillary evolution.

  2. Experimental study on capillary filling in nanochannels

    Science.gov (United States)

    Yang, Min; Cao, Bing-Yang; Wang, Wei; Yun, He-Ming; Chen, Bao-Ming

    2016-10-01

    We investigated the capillary filling kinetics of deionized water in nanochannels with heights of 50-120 nm. The measured position of the moving meniscus was proportional to the square root of time, as predicted by the LW equation. However, the extracted slopes were significantly smaller than the predictions based on the bulk properties. This unusual behavior was found to be mainly caused by the electro-viscous effect and dynamic contact angle, which was significantly larger than the static angle. In addition, when the filling distance reached about 600 μm, bubbles tended to be formed, leading to the main meniscus was almost immobile.

  3. Capillary zone electrophoresis and packed capillary column liquid chromatographic analysis of recombinant human interleukin-4.

    Science.gov (United States)

    Bullock, J

    1993-02-24

    Capillary zone electrophoresis (CZE) and packed capillary column liquid chromatography (micro-LC) have been applied to the analysis of the recombinant human protein interleukin-4 (rhIL-4). Separations for both the parent protein and its enzymatic digest were developed for the purpose of characterizing protein purity and identity. CZE separations of the intact protein were investigated over the pH range of 4.5 to 8.0 using uncoated fused silica capillaries. Gradient reversed-phase micro-LC was performed using 0.32 mm packed capillary columns at flow-rates of 5-6 microliters/min. Emphasis was placed on the ability of these methods to separate close structural variants and degradation products of the protein. Peptide mapping of the tryptic digest of rhIL-4 using a combination of CZE and micro-LC provided complimentary high resolution methods for establishing protein identity. Reproducible separations were achieved using sub-picomol amounts of sample. The advantages and problems encountered with these two techniques for characterizing rhIL-4 were assessed. PMID:8450025

  4. Capacitively coupled contactless conductivity detection and sequential injection analysis in capillary electrophoresis and capillary electro-chromatography

    OpenAIRE

    Mai, Thanh Duc

    2011-01-01

    This thesis focuses on the applications of capacitively coupled contactless conductivity detection (C4D) in capillary electrophoresis (CE) hybridized with high-performance liquid chromatography (HPLC), i.e. in capillary electrochromatography and pressure-assisted capillary electrophoresis, as well as on the development and applications of an extension of CE-C4D with sequential injection analysis (SIA). At first, the in-house built C4D was used for electro-chromatographic determinations of...

  5. Numerical study on flow rate limitation of open capillary channel flow through a wedge

    Directory of Open Access Journals (Sweden)

    Ting-Ting Zhang

    2016-04-01

    Full Text Available The flow characteristics of slender-column flow in wedge-shaped channel under microgravity condition are investigated in this work. The one-dimensional theoretical model is applied to predict the critical flow rate and surface contour of stable flow. However, the one-dimensional model overestimates the critical flow rate for not considering the extra pressure loss. Then, we develop a three-dimensional simulation method with OpenFOAM, a computational fluid dynamics tool, to simulate various phenomena in wedge channels with different lengths. The numerical results are verified with the capillary channel flow experimental data on the International Space Station. We find that the three-dimensional simulation perfectly predicts the critical flow rates and surface contours under various flow conditions. Meanwhile, the general behaviors in subcritical, critical, and supercritical flow are studied in three-dimensional simulation considering variations of flow rate and open channel length. The numerical techniques for three-dimensional simulation is validated for a wide range of configurations and is hopeful to provide valuable guidance for capillary channel flow experiment and efficient liquid management in space.

  6. How Critical Is Critical Thinking?

    Science.gov (United States)

    Shaw, Ryan D.

    2014-01-01

    Recent educational discourse is full of references to the value of critical thinking as a 21st-century skill. In music education, critical thinking has been discussed in relation to problem solving and music listening, and some researchers suggest that training in critical thinking can improve students' responses to music. But what exactly is…

  7. Critically Thinking about Critical Thinking

    Science.gov (United States)

    Weissberg, Robert

    2013-01-01

    In this article, the author states that "critical thinking" has mesmerized academics across the political spectrum and that even high school students are now being called upon to "think critically." He furthers adds that it is no exaggeration to say that "critical thinking" has quickly evolved into a scholarly…

  8. Crude Glycerol as Cost-Effective Fuel for Combined Heat and Power to Replace Fossil Fuels, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, William L

    2012-10-31

    The primary objectives of this work can be summed into two major categories. Firstly, the fundamentals of the combustion of glycerol (in both a refined and unrefined form) were to be investigated, with emphasis of the development of a system capable of reliably and repeatedly combusting glycerol as well as an analysis of the emissions produced during glycerol combustion. Focus was placed on quantifying common emissions in comparison to more traditional fuels and this work showed that the burner developed was able to completely combust glycerol within a relatively wide range of operating conditions. Additionally, focus was placed on examining specific emissions in more detail, namely interesting NOx emissions observed in initial trials, acrolein and other volatile organic emissions, and particulate and ash emissions. This work showed that the combustion of crude glycerol could result in significantly reduced NOx emissions as a function of the high fuel bound oxygen content within the glycerol fuel. It also showed that when burned properly, the combustion of crude glycerol did not result in excessive emissions of acrolein or any other VOC compared to the combustion from more traditional fuels. Lastly however, this work has shown that in any practical application in which glycerol is being burned, it will be necessary to explore ash mitigation techniques due to the very high particulate matter concentrations produced during glycerol combustion. These emissions are comparable to unfiltered coal combustion and are directly tied to the biodiesel production method. The second focus of this work was directed to developing a commercialization strategy for the use of glycerol as a fuel replacement. This strategy has identified a 30 month plan for the scaling up of the laboratory scale burner into a pre-pilot scale system. Additionally, financing options were explored and an assessment was made of the economics of replacing a traditional fuel (namely natural gas) with crude

  9. L-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss.

    Science.gov (United States)

    Murakami, Nao; Oba, Mana; Iwamoto, Mariko; Tashiro, Yukihiro; Noguchi, Takuya; Bonkohara, Kaori; Abdel-Rahman, Mohamed Ali; Zendo, Takeshi; Shimoda, Mitsuya; Sakai, Kenji; Sonomoto, Kenji

    2016-01-01

    Glycerol is a by-product in the biodiesel production process and considered as one of the prospective carbon sources for microbial fermentation including lactic acid fermentation, which has received considerable interest due to its potential application. Enterococcus faecalis isolated in our laboratory produced optically pure L-lactic acid from glycerol in the presence of acetic acid. Gas chromatography-mass spectrometry analysis using [1, 2-(13)C2] acetic acid proved that the E. faecalis strain QU 11 was capable of converting acetic acid to ethanol during lactic acid fermentation of glycerol. This indicated that strain QU 11 restored the redox balance by oxidizing excess NADH though acetic acid metabolism, during ethanol production, which resulted in lactic acid production from glycerol. The effects of pH control and substrate concentration on lactic acid fermentation were also investigated. Glycerol and acetic acid concentrations of 30 g/L and 10 g/L, respectively, were expected to be appropriate for lactic acid fermentation of glycerol by strain QU 11 at a pH of 6.5. Furthermore, fed-batch fermentation with 30 g/L glycerol and 10 g/L acetic acid wholly exhibited the best performance including lactic acid production (55.3 g/L), lactic acid yield (0.991 mol-lactic acid/mol-glycerol), total yield [1.08 mol-(lactic acid and ethanol)]/mol-(glycerol and acetic acid)], and total carbon yield [1.06 C-mol-(lactic acid and ethanol)/C-mol-(glycerol and acetic acid)] of lactic acid and ethanol. In summary, the strain QU 11 successfully produced lactic acid from glycerol with acetic acid metabolism, and an efficient fermentation system was established without carbon loss.

  10. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    Directory of Open Access Journals (Sweden)

    J. P. Bender

    2008-09-01

    Full Text Available This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE, liquid-liquid (LLE and vapor-liquid-liquid (VLLE equilibrium were recorded. It was experimentally observed that, at a given temperature and surfactant content, an increase in the concentration of glycerol/oil ratio led to a pronounced increase in the slope of the liquid-liquid coexistence curve. A comparison with results reported for the same system but using propane as solvent showed that much lower pressure transition values are obtained when using n-butane.

  11. Uptake and translocation of arsenite by Pteris vittata L.: effects of glycerol, antimonite and silver.

    Science.gov (United States)

    Mathews, Shiny; Rathinasabapathi, Bala; Ma, Lena Q

    2011-12-01

    AsIII uptake in living cells is through aquaglyceroporin transporters, but it is unknown in arsenic-hyperaccumulator Pteris vittata. We investigated the effects of AsIII analogs glycerol and antimonite (SbIII) at 0-100 mM and aquaporin inhibitor AgNO(3) at 0-0.1 mM on the uptake of 0.1 mM AsIII or AsV by P. vittata over 1-2 h. Glycerol or SbIII didn't impact AsIII or AsV uptake by P. vittata (p aquaporin transporter different from glycerol and SbIII transporters. Further as AsIII analogs and aquaporin inhibitor had no impact on AsV uptake, AsIII and AsV were likely taken up by different transporters in P. vittata. Our results imply a different AsIII transporter in P. vittata from other plants.

  12. Effect of pressure on the α relaxation in glycerol and xylitol

    Science.gov (United States)

    Paluch, M.; Casalini, R.; Hensel-Bielowka, S.; Roland, C. M.

    2002-06-01

    The effect of pressure on the dielectric relaxation of two polyhydroxy alcohols is examined by analysis of existing data on glycerol, together with new measurements on xylitol. The fragility, or Tg-normalized temperature dependence, changes with pressure for low pressures, but becomes invariant above 1 GPa. When compared at temperatures for which the α-relaxation times are equal, there is no effect of pressure (xylitol show an excess intensity at higher frequencies. For xylitol, unlike for glycerol, at lower temperatures this wing disjoins to form a separate peak. For both glass formers, elevated pressure causes the excess wing to become more separated from the peak maximum; that is, the properties of the primary and excess intensities are not correlated. This implies that the excess wing in glycerol is also a distinct secondary process, although it cannot be resolved from the primary peak.

  13. Human skeletal muscle fatty acid and glycerol metabolism during rest, exercise and recovery

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Sacchetti, M; Rådegran, G;

    2002-01-01

    and release decreased slowly and reached constant values after approximately 1.5 h of recovery similar to pre-exercise. Whole body FA reesterification (FA R(d) - FA oxidation; R(d), rate of disappearance) was approximately 400 micromol min(-1) at rest and during exercise, and increased during recovery to 495......This study was conducted to investigate skeletal muscle fatty acid (FA) and glycerol kinetics and to determine the contribution of skeletal muscle to whole body FA and glycerol turnover during rest, 2 h of one-leg knee-extensor exercise at 65 % of maximal leg power output, and 3 h of recovery......-calculated leg FA and glycerol release. The whole body FA rate of appearance (R(a)) increased with exercise and decreased rapidly in recovery but stayed higher compared to pre-exercise. The leg net FA uptake decreased immediately on cessation of exercise to near pre-exercise level, but the tracer FA uptake...

  14. An isocratic HPLC method for the determination of sorbitol and glycerol in pharmaceutical formulations.

    Science.gov (United States)

    Simonzadeh, Ninus; Ronsen, Bruce

    2012-08-01

    Sorbitol and glycerol, along with other inactive ingredients such as preservatives and dyes, are commonly used in various pharmaceutical and personal care products. To accurately assess the effectiveness of various formulations containing sorbitol and/or glycerol, their quantitative determination is essential. In the current study, two types of detectors (a Varian evaporative light scattering detector and an Agilent ultraviolet-visible detector) are evaluated for the assay of working sample solutions. The two detection techniques are complimentary, and a comparison of the results obtained using the two detectors is presented here. The current method is shown to be stability-indicating and free from interference from any of the formulation excipients and potential degradation products. The method is reproducible, accurate, sensitive and selective. It provides enhanced detection sensitivity for sorbitol and comparable sensitivity for glycerol versus similar methods reported in the literature that utilize a refractive index detector for the analysis of either of the two polyols. PMID:22565491

  15. Design and Control of Glycerol-tert-Butyl Alcohol Etherification Process

    Directory of Open Access Journals (Sweden)

    Elena Vlad

    2012-01-01

    Full Text Available Design, economics, and plantwide control of a glycerol-tert-butyl alcohol (TBA etherification plant are presented. The reaction takes place in liquid phase, in a plug flow reactor, using Amberlyst 15 as a catalyst. The products' separation is achieved by two distillation columns where high-purity ethers are obtained and a section involving extractive distillation with 1,4-butanediol as solvent, which separates TBA from the TBA/water azeotrope. Details of design performed in AspenPlus and an economic evaluation of the process are given. Three plantwide control structures are examined using a mass balance model of the plant. The preferred control structure fixes the fresh glycerol flow rate and the ratio glycerol + monoether : TBA at reactor-inlet. The stability and robustness in the operation are checked by rigorous dynamic simulation in AspenDynamics.

  16. Optimization for microwave-assisted direct liquefaction of bamboo residue in glycerol/methanol mixtures

    Institute of Scientific and Technical Information of China (English)

    Jiulong Xie; Jinqiu Qi; Chungyun Hse; Todd F. Shupe

    2015-01-01

    Bamboo residues were liquefied in a mixture of glycerol and methanol in the presence of sulfuric acid using microwave energy. We investigated the effects of lique-faction conditions, including glycerol/methanol ratio, liq-uefaction temperature, and reaction time on the conversion yield. The optimal liquefaction conditions were under the temperature of 120 °C, the reaction time of 7 min, the glycerol–methanol–bamboo ratio of 8/0/2 (W/W), and the microwave power of 300 W. Maximum conversion yield was 96.7%. The liquid products were separated into two contents (water soluble part and precipitate part) by addi-tion of a sufficient amount of water. By Fourier transform infrared (FT-IR), the water soluble content mainly con-tained glycerol and its derivate and carbohydrate degra-dation products, and the precipitate content was mainly lignin derivatives.

  17. Differences in [14C]glycerol utilization in normal and familial hypercholesterolemic fibroblasts

    International Nuclear Information System (INIS)

    It is known that cultured fibroblasts from familial hypercholesterolemia (FH) patients lack the normal cell receptor for low density lipoprotein (LDL) and that the absence of receptor-mediated transport of LDL cholesterol into these cells results in increased cellular synthesis of cholesterol. After 20 h perincubation in lipid-free medium, cultured FH fibroblasts incorporated significantly greater amounts of [14C]glycerol into cellular lipids than did normal fibroblasts. Relative to the control medium which contained only bovine serum albumin (BSA), preincubation with 5% fetal bovine serum or 50 micrograms LDL/ml decreased [14C]glycerol incorporation by both cell types. FH cells utilized more [14C]glycerol for phospholipid synthesis and less for triglyceride synthesis than normal cells. This study indicates that LDL may be important in the transport of glycerides, as well as cholesterol, to cells

  18. Synthesis and Antibacterial and Antibiofilm Activity of Iron Oxide Glycerol Nanoparticles Obtained by Coprecipitation Method

    Directory of Open Access Journals (Sweden)

    Simona Liliana Iconaru

    2013-01-01

    Full Text Available The glycerol iron oxide nanoparticles (GIO-NPs were obtained by an adapted coprecipitation method. The X-ray diffraction (XRD studies demonstrate that GIO-NPs were indexed into the spinel cubic lattice with a lattice parameter of 0.835 nm. The refinement of XRD spectra indicated that no other phases except maghemite were detected. The adsorption of glycerol on iron oxide nanoparticles was investigated by Fourier transform infrared (FTIR spectroscopy. On the other hand, this work implicated the use of GIO-NPs in antibacterial studies. The results indicate that, in the case of P. aeruginosa  1397 biofilms, at concentrations from 0.01 mg/mL to 0.625 mg/mL, the glycerol iron oxide inhibits the ability of this strain to develop biofilms on the inert substratum.

  19. Catalytic Technologies for Biodiesel Fuel Production and Utilization of Glycerol: A Review

    Directory of Open Access Journals (Sweden)

    Yasuaki Maeda

    2012-03-01

    Full Text Available More than 10 million tons of biodiesel fuel (BDF have been produced in the world from the transesterification of vegetable oil with methanol by using acid catalysts (sulfuric acid, H2SO4, alkaline catalysts (sodium hydroxide, NaOH or potassium hydroxide, KOH, solid catalysts and enzymes. Unfortunately, the price of BDF is still more expensive than that of petro diesel fuel due to the lack of a suitable raw material oil. Here, we review the best selection of BDF production systems including raw materials, catalysts and production technologies. In addition, glycerol formed as a by-product needs to be converted to useful chemicals to reduce the amount of glycerol waste. With this in mind, we have also reviewed some recent studies on the utilization of glycerol.

  20. Potential of glycerol and soybean oil for bioremediation of weathered oily-sludge contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, T.C.F.; Franca, F.P. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica], E-mail: fpfranca@eq.ufrj.br; Oliveira, F.J.S. [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2012-04-15

    The bioremediation of petroleum-contaminated soil was investigated on laboratory scale. This work evaluated the effect of co-substrate addition in tropical climate soil highly contaminated with oily residue. Glycerol and soybean oil were used as auxiliary co-substrates for contaminant degradation. Three different concentrations of co-substrate were tested, and the experiments were carried out over 60 days. The following parameters were monitored: humidity, pH, total heterotrophic bacteria, total fungi, total petroleum hydrocarbons (TPH), and the concentrations of benzo[a]pyrene and chrysene. The soil supplementation with renewable co-substrates improved the efficiency of the biodegradation TPH, with removals of 85% and 83% for glycerol and soybean oil, respectively, compared to a 55% removal yielded by the biodegradation process without supplementation. The use of glycerol increased Chrysene and Benzo[a]pyrene biodegradation by 50%, while soybean oil supplementation increased their removal by 36%. (author)

  1. Techno-economic risk analysis of glycerol biorefinery concepts against market price fluctuation

    DEFF Research Database (Denmark)

    Gargalo, Carina L.; Cheali, Peam; Gernaey, Krist;

    A biorefinery integrates biomass conversion processes to produce fuels, power, and chemicals from bio-based feedstock. Through the synthesis of several products, a biorefinery can benefit from the differences in biomass composition and make the most of the value derived from the biomass feedstock...... sustainable design framework developed earlier [16] [1] [17] [10]. The economic risk analysis enables the user to perform a comprehensive assessment of alternatives using a probabilistic framework which helps to design a robust and competitive glycerol biorefinery....... glycerol prices. Therefore, in order to increase the economic competitiveness of the biodiesel industry, there is an increasing interest in adding value using the glycerol waste stream as feedstock for the synthesis of bio-derived building block compounds and polymers [5] [6] [7] [8] [4] [9]. Moreover...

  2. Effects of a physiological GH pulse on interstitial glycerol in abdominal and femoral adipose tissue

    DEFF Research Database (Denmark)

    Gravhølt, C H; Schmitz, Ole; Simonsen, L;

    1999-01-01

    .0005). Administration of GH induced an increase in interstitial glycerol in both abdominal and femoral adipose tissue (ANOVA: abdominal, P = 0. 04; femoral, P = 0.03). There was no overall difference in the response to GH in the two regions during the study period as a whole (ANOVA: P = 0.5), but during peak...... stimulation of lipolysis abdominal adipose tissue was, in absolute but not in relative terms, stimulated more markedly than femoral adipose tissue (ANOVA: P = 0. 03 from 45 to 225 min). Peak interstitial glycerol values of 253 +/- 37 and 336 +/- 74 micromol/l were seen after 135 and 165 min in femoral...... and abdominal adipose tissue, respectively. ATBF was not statistically different in the two situations (ANOVA: P = 0.7). In conclusion, we have shown that a physiological pulse of GH increases interstitial glycerol concentrations in both femoral and abdominal adipose tissue, indicating activated lipolysis...

  3. Differences in ( sup 14 C)glycerol utilization in normal and familial hypercholesterolemic fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Shireman, R.B.; Durieux, J. (Univ. of Florida Gainesville (USA))

    1991-01-01

    It is known that cultured fibroblasts from familial hypercholesterolemia (FH) patients lack the normal cell receptor for low density lipoprotein (LDL) and that the absence of receptor-mediated transport of LDL cholesterol into these cells results in increased cellular synthesis of cholesterol. After 20 h perincubation in lipid-free medium, cultured FH fibroblasts incorporated significantly greater amounts of ({sup 14}C)glycerol into cellular lipids than did normal fibroblasts. Relative to the control medium which contained only bovine serum albumin (BSA), preincubation with 5% fetal bovine serum or 50 micrograms LDL/ml decreased ({sup 14}C)glycerol incorporation by both cell types. FH cells utilized more ({sup 14}C)glycerol for phospholipid synthesis and less for triglyceride synthesis than normal cells. This study indicates that LDL may be important in the transport of glycerides, as well as cholesterol, to cells.

  4. Branched glycerol dialkyl glycerol tetraethers and crenarchaeol record post-glacial sea level rise and shift in source of terrigenous brGDGTs in the Kara Sea (Arctic Ocean)

    NARCIS (Netherlands)

    de Jonge, C.; Stadnitskaia, Alina; Cherkashov, G.; Sinninghe Damste, J.S.

    2016-01-01

    This study evaluates the glycerol dialkyl glycerol tetraether (GDGT) distribution and provenance in sediments(spanning a minimum of 13.3 ka) from the St. Anna Trough (Northern Kara Sea). The site has experiencedextensive fluctuation in the delivery of river-derived organic matter (OM), caused by a e

  5. Biodiesel biorefinery: opportunities and challenges for microbial production of fuels and chemicals from glycerol waste

    Directory of Open Access Journals (Sweden)

    Almeida João R M

    2012-07-01

    Full Text Available Abstract The considerable increase in biodiesel production worldwide in the last 5 years resulted in a stoichiometric increased coproduction of crude glycerol. As an excess of crude glycerol has been produced, its value on market was reduced and it is becoming a “waste-stream” instead of a valuable “coproduct”. The development of biorefineries, i.e. production of chemicals and power integrated with conversion processes of biomass into biofuels, has been singled out as a way to achieve economically viable production chains, valorize residues and coproducts, and reduce industrial waste disposal. In this sense, several alternatives aimed at the use of crude glycerol to produce fuels and chemicals by microbial fermentation have been evaluated. This review summarizes different strategies employed to produce biofuels and chemicals (1,3-propanediol, 2,3-butanediol, ethanol, n-butanol, organic acids, polyols and others by microbial fermentation of glycerol. Initially, the industrial use of each chemical is briefly presented; then we systematically summarize and discuss the different strategies to produce each chemical, including selection and genetic engineering of producers, and optimization of process conditions to improve yield and productivity. Finally, the impact of the developments obtained until now are placed in perspective and opportunities and challenges for using crude glycerol to the development of biodiesel-based biorefineries are considered. In conclusion, the microbial fermentation of glycerol represents a remarkable alternative to add value to the biodiesel production chain helping the development of biorefineries, which will allow this biofuel to be more competitive.

  6. Design of a recombinant Escherichia coli for producing L-phenylalanine from glycerol.

    Science.gov (United States)

    Thongchuang, Mayura; Pongsawasdi, Piamsook; Chisti, Yusuf; Packdibamrung, Kanoktip

    2012-10-01

    A recombinant Escherichia coli was engineered to produce the commercially important amino acid L-phenylalanine (L-Phe) using glycerol as the carbon source. Compared to the conventionally used glucose and sucrose, glycerol is a less expensive carbon source. As phenylalanine dehydrogenase (PheDH) activity is involved in the last step of L-Phe synthesis in E. coli, a phenylalanine dehydrogenase gene (phedh) from the thermotolerant Bacillus lentus was cloned into pRSFDuet-1 (pPheDH) and expressed in E. coli BL21(DE3). The resulting clone had a limited ability to produce L-Phe from glycerol, possibly because of a poor glycerol uptake by the cell, or an inability to excrete L-Phe, or both. Therefore, yddG gene encoding an aromatic amino acid exporter and glpF gene encoding a glycerol transport facilitator were coexpressed with the phedh in a reengineered E. coli. In a glycerol medium, the maximum L-Phe production rates of the clones pPY (phedh and yddG genes) and pPYF (phedh, yddG and glpF genes) were 1.4- and 1.8-fold higher than the maximum production rate of the pPheDH clone. The better producing pPYF clone was further evaluated in a 5 l stirred-tank fermenter (37 °C, an aeration rate of 1 vvm, an agitation speed of 400 rpm). In the fermenter, the maximum concentration of L-Phe (366 mg/l) was achieved in a much shorter period compared to in the shake flasks. In the latter, the highest titer of L-Phe was only 76 % of the maximum value attained in the fermenter. PMID:22806734

  7. Effect of glycerol on mechanical and physical properties of silver-chitosan nanocomposite films

    Science.gov (United States)

    Susilowati, E.; Kartini, I.; Santosa, S. J.; Triyono

    2016-02-01

    The effect of using glycerol as plasticizer on mechanical and physical properties of silver-chitosan nanocomposite films have been studied. The nanocomposite films were prepared via three steps consisting of silver-chitosan colloidal nanocomposites preparation, adding of glycerol to colloids and silver-chitosan nanocomposites films formation. During the first step, silver ions were reduced by glucose and accelerated by sodium hydroxide (NaOH). Chitosan of 1% (v/v) act as stabilizing agent. Glycerol with volume variation of 0.2, 0.4, 0.6, 8 and 1.0 mL was added colloidal nanocomposites of 60 mL on the second step. On the third step, colloidal nanocomposites were cast on the polypropylene plate and dried at room temperature. The as-prepared films were then neutralized by NaOH and rinsed with distilled water until the filtrate reached the pH of 7. The colloidal nanocomposites were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The film were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The mechanical properties, swelling capacity, water vapor permeability (WVP) of the films were also studied. The results indicated that the addition of different amounts of glycerol on colloidal nanocomposites effects on mechanical and physical properties of the resulted nanocomposite films. The elongation and tensile strength were gradually increased as the glycerol amount. Meanwhile, the swelling capacity, WVP, and crystallinity of the film also showed enhancement at increasing glycerol amount. However, the thermal stability decreased.

  8. Nonlinear Mathematical Simulation and Analysis of Dha Regulon for Glycerol Metabolism in Klebsiella pneumoniae

    Institute of Scientific and Technical Information of China (English)

    孙亚琴; 叶剑雄; 牟晓佳; 滕虎; 冯恩民; 曾安平; 修志龙

    2012-01-01

    Glycerol may be converted to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under anaerobic conditions and glycerol dismutation involves two parallel pathways controlled by the dha regulon. In this study, a fourteen-dimensional nonlinear dynamic system is presented to describe the continuous culture and multiplicity analysis, in which two regulated negative-feedback mechanisms of repression and enzyme inhibition are investigated. The model describing the expression of gene-mRNA-enzyme-product was established according to the repression of the dha regulon by 3-hydroxypropionaldehy (3-HPA). Comparisons between simulated and experimental results indicate that the model can be used to describe the production of 1,3-PD under continuous fermentation. The new model is translated into the corresponding S-system version. The robustness of this model is discussed by using the S-system model and the sensitivity analysis shows that the model is sufficiently robust. The influences of initial glycerol concentration and dilution rate on the biosynthesis of 1,3-PD and the stability of the dha regulon model are investigated. The intracellular concentrations of glycerol, 1,3-PD, 3-HPA, repressor mRNA, repressor, mRNA and protein levels of glycerol dehydratase (GDHt) and 1,3-PD oxydoreductase (PDOR) can be predicted for continuous cultivation. The results of simulation and analysis indicate that 3-HPA accumulation will repress the expression of the dha regulon at the transcriptional level. This model gives new insights into the regulation of glycerol metabolism in K. pneumoniae and explain some of the experimental observations.

  9. Capillary surface discontinuities above reentrant corners

    Science.gov (United States)

    Korevaar, H. J.

    1982-01-01

    A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.

  10. CMOS absorbance detection system for capillary electrophoresis

    International Nuclear Information System (INIS)

    This paper presents a cost-effective portable photodetection system for capillary electrophoresis absorptiometry. By using a CMOS BDJ (buried double p-n junction) detector, a dual-wavelength method for absorbance measurement is implemented. This system includes associated electronics for low-noise pre-amplification and A/D conversion, followed by digital signal acquisition and processing. Two signal processing approaches are adopted to enhance the signal to noise ratio. One is variable time synchronous detection, which optimizes the sensitivity and measuring rate compared to a conventional synchronous detection technique. The other is a statistical approach based on principal component analysis, which allows optimal estimation of detected signal. This system has been designed and tested in capillary electrophoresis conditions. Its operation has been verified with performances comparable to those of a commercialized spectrophotometric system (HP-3D CE). With potential on-chip integration of associated electronics, it may be operated as an integrable detection module for microchip electrophoresis and other microanalysis systems

  11. Capillary wrinkling of thin bilayer polymeric sheets

    Science.gov (United States)

    Chang, Jooyoung; Menon, Narayanan; Russell, Thomas

    We have investigated capillary force induced wrinkling on a floated polymeric bilayer thin sheet. The origin of the wrinkle pattern is compressional hoop stress caused by the capillary force of a water droplet placed on the floated polymeric thin sheet afore investigated. Herein, we study the effect of the differences of surface energy arising from the hydrophobicity of Polystyrene (PS Mw: 97 K, Contact Angle: 88 º) and the hydrophilicity of Poly(methylmethacrylate) (PMMA Mw: 99K, Contact Angle: 68 º) on two sides of a bilayer film. We measure the number and the length of the wrinkles by broadly varying the range of thicknesses of top (9 nm to 550 nm) and bottom layer (25 nm to 330 nm). At the same, there is only a small contrast in mechanical properties of the two layers (PS E = 3.4 GPa, and PMMA E = 3 GPa). The number of the wrinkles is not strongly affected by the composition (PS(Top)/PMMA(Bottom) or PMMA(Top)/PS(Bottom)) and the thickness of each and overall bilayer system. However, the length of the wrinkle is governed by the contact angle of the drop on the top layer of bilayer system. We also compare this to the wrinkle pattern obtained in monolayer systems over a wide range of thickness from PS and PMMA (7 nm to 1 μm). W.M. Keck Foundation.

  12. Using capillary electrophoresis to characterize polymeric particles.

    Science.gov (United States)

    Riley, Kathryn R; Liu, Sophia; Yu, Guo; Libby, Kara; Cubicciotti, Roger; Colyer, Christa L

    2016-09-01

    Capillary electrophoresis (CE) was used for the characterization of a variety of polymeric micron and sub-micron particles based on size, surface functionality, and binding properties. First, a robust capillary zone electrophoresis (CZE) method was developed for the baseline separation and quantitation of commercially available polystyrene particles with various surface modifications (including amino, carboxylate, and sulfate functional groups) and various sizes (0.2, 0.5, 1.0, and 3.0μm). The separation of DNA-templated polyacrylamide particles from untemplated particles (as used for the Ion Torrent Personal Genome Machine) was demonstrated. Finally, using the 29-base thrombin aptamer and thrombin protein as a model system, a study was undertaken to determine dissociation constants for the aptamer and protein in free solution and when the aptamer was conjugated to a particle, with the goal of better understanding how the use of solid substrates, like particles, affects selection and binding processes. Dissociation constants were determined and were found to be approximately 5-fold higher for the aptamer conjugated to a particle relative to that in free solution. PMID:27543386

  13. 1,3-Propanediol production from crude glycerol from Jatropha biodiesel process.

    Science.gov (United States)

    Hiremath, Anand; Kannabiran, Mithra; Rangaswamy, Vidhya

    2011-01-31

    The present report describes production of 1,3-propanediol by Klebsiella pneumoniae ATCC 15380 from crude glycerol from jatropha biodiesel process. Optimization resulted in a yield of up to 56g/L of 1,3-propanediol. A conversion rate of 0.85mol 1,3-propanediol/mol of glycerol has been obtained. Downstream processing to isolate 1,3-propanediol from the fermentation broth resulted in 99.7% pure product with a recovery of 34%. The pure 1,3-propanediol was polymerized with terephthalic acid successfully to yield polytrimethylene terephthalate.

  14. A physicochemical study of sugar palm (Arenga Pinnata) starch films plasticized by glycerol and sorbitol

    Science.gov (United States)

    Poeloengasih, Crescentiana D.; Pranoto, Yudi; Hayati, Septi Nur; Hernawan, Rosyida, Vita T.; Prasetyo, Dwi J.; Jatmiko, Tri H.; Apriyana, Wuri; Suwanto, Andri

    2016-02-01

    The present work explores the physicochemical characteristics of sugar palm starch film for a potential hard capsule purpose. Sugar palm (Arenga pinnata) starch films were plasticized with glycerol or sorbitol in various concentrations (30% up to 50% w/w starch). Their effects on physicochemical properties of the films were investigated. The results showed that sugar palm starch was successfully developed as the main material of film using casting method. Incorporation of both glycerol or sorbitol affected the properties of films in different ways. It was found that thickness and solubility increased as plasticizer concentration increased, whereas retraction ratio, swelling degree and swelling thickness decreased with the increased plasticizer concentration.

  15. Steam Reforming of Glycerol for Hydrogen Production over Ni/SiO2 Catalyst

    OpenAIRE

    Sadanandam, G.; Sreelatha, N.; Phanikrishna Sharma, M. V.; Kishta Reddy, S.; B. Srinivas; Venkateswarlu, K.; Krishnudu, T.; Subrahmanyam, M.; Durga Kumari, V.

    2012-01-01

    The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results in...

  16. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    OpenAIRE

    J. P. Bender; A. Junges; Franceschi, E.; F. C. Corazza; C. Dariva; J. Vladimir Oliveira; M. L. Corazza

    2008-01-01

    This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE), liquid-liquid (L...

  17. Glycerol Containing Triacetylborate Mediated Syntheses of Novel 2-Heterostyryl Benzimidazole Derivatives: A Green Approach

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Taduri

    2014-01-01

    Full Text Available A very simple, mild, efficient, and novel green methodology has been developed for the syntheses of some 2-hetero/styryl-benzimidazoles. Title compounds were synthesized by the condensation of o-phenylenediamine with cinnamic acids at 150–180°C for 5-6 h using glycerol containing triacetylborate (10–20 mol% as the reaction medium. In an alternative approach, condensation of 2-methylbenzimidazole derivatives with aromatic aldehydes was done using glycerol containing triacetylborate (10–20 mol% as the reaction medium.

  18. Esterification of glycerol with acetic acid over dodecamolybdophosphoric acid encaged in USY zeolite

    OpenAIRE

    Ferreira, P; Fonseca, I.; Ramos, A.; Vital, J; Castanheiro, Jose

    2009-01-01

    The esterification of glycerol with acetic acid was carried out over dodecamolybdophosphoric acid (PMo) encaged in the USY zeolite. The products of glycerol acetylation were monoacetin, diacetin and triacetin. A series of PMo encaged in the NaUSY zeolite with different PMo loading from 0.6 to 5.4 wt.% were prepared. It was observed that the catalytic activity increases with the amount of PMo immobilized in the NaUSY zeolite, being the PMo3_NaUSY (with 1.9 wt.%) the most active sample...

  19. A cost effective fermentative production of glutathione by Saccharomyces cerevisiae with cane molasses and glycerol

    OpenAIRE

    Andréia Anschau; Lucielen Oliveira dos Santos; Ranulfo Monte Alegre

    2013-01-01

    This work aimed to evaluate the effect of sugar cane molasses and glycerol on glutathione (GSH) fermentation by Saccharomyces cerevisiae ATCC 7754 in flask culture using response surface methodology. Under optimized conditions (80 g/L of molasses and 60 g/L of glycerol), the highest GSH and biomass concentration achieved were 119.6 mg/L and 25.3 g/L, respectively. Further studies done in 5 L bioreactor resulted 241.3 mg/L GSH after 96 h in batch fermentation without amino acids addition and t...

  20. Poly(glycerol adipate)-fatty acid esters as versatile nanocarriers

    DEFF Research Database (Denmark)

    Weiss, Verena M; Naolou, Toufik; Hause, Gerd;

    2012-01-01

    Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate) and their sub......Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate...

  1. Selective Oxidation of Raw Glycerol Using Supported AuPd Nanoparticles

    Directory of Open Access Journals (Sweden)

    Carine E. Chan-Thaw

    2015-02-01

    Full Text Available Bimetallic AuPd supported on different carbonaceous materials and TiO2 was tested in the liquid phase oxidation of commercial grade and raw glycerol. The latter was directly obtained from the base-catalyzed transesterification of edible rapeseed oil using KOH. The best catalytic results were obtained using activated carbon and nitrogen-functionalized carbon nanofibers as supports. In fact, the catalysts were more active using pure glycerol instead of the one obtained from rapeseed, where strong deactivation phenomena were present. Fourier transform infrared (FT-IR and TEM were utilized to investigate the possible reasons for the observed loss of activity.

  2. Critical superconductors

    OpenAIRE

    Vagov, A.; Shanenko, A. A.; M. V. Milošević; Axt, V. M.; Vinokur, V. M.; Peeters, F. M.

    2013-01-01

    Bogomolnyi critical point, originally introduced in string theories, is fundamental to superconductivity. At the critical temperature T_c it marks the sharp border between ideally diamagnetic bulk type-I superconductors and type-II ones that can host vortices, while itself it harbors infinitely degenerate distributions of magnetic flux in the superconducting state. Here we show that below T_c the physics of the Bogomolnyi critical point projects onto a wider range of microscopic parameters, e...

  3. Criticality Model

    Energy Technology Data Exchange (ETDEWEB)

    A. Alsaed

    2004-09-14

    The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of

  4. A Simple Double-Source Model for Interference of Capillaries

    Science.gov (United States)

    Hou, Zhibo; Zhao, Xiaohong; Xiao, Jinghua

    2012-01-01

    A simple but physically intuitive double-source model is proposed to explain the interferogram of a laser-capillary system, where two effective virtual sources are used to describe the rays reflected by and transmitted through the capillary. The locations of the two virtual sources are functions of the observing positions on the target screen. An…

  5. Soft x-ray amplification in an ablative capillary discharge

    International Nuclear Information System (INIS)

    Soft x-ray amplification in CVI 18.2 nm line is observed in an ablative UHMW-PE capillary discharge. The gain coefficient is measured to be 1.9 cm-1. The electron density is about 2 x 1019 cm-3. This indicates that capillary discharge pumping device can be a source for a compact soft x-ray laser. (author)

  6. Potential of capillary electrophoresis for the profiling of propolis

    NARCIS (Netherlands)

    Hilhorst, M.J; Somsen, G.W; de Jong, G.J.

    1998-01-01

    The usefulness of capillary electrophoresis (CE) with diode array detection for the profiling of Propolis, a hive product, is investigated. Water extracts of Propolis were analyzed with both capillary zone electrophoresis (CZE) at pH 7.0 and 9.3, and micellar electrokinetic chromatography (MEKC) wit

  7. Analysis of organic acids in Macedonian wines by capillary electrophoresis

    OpenAIRE

    Jancovska, Maja; Ivanova, Violeta; Gulaboski, Rubin; Belder, Detlev

    2013-01-01

    Capillary electrophoresis as a separation technique can be applied for analysis of organic acids in white and red wines, providing high resolution separation of the analytes. Organic acids such as of tartaric, malic, lactic citric and succinic acids have been analysed in many Macedonian red and white wines by capillary electrophoresis, and results have been discussed.

  8. Blepharospasm in a patient with pontine capillary telangiectasia

    OpenAIRE

    Gilbert, AL; Dillon, WP; Horton, JC

    2012-01-01

    Blepharospasm is rarely due to an identifiable etiology. In the majority of cases, imaging fails to reveal any structural lesion. Here we describe an otherwise healthy patient with blepharospasm who was found to have pontine capillary telangiectasia. We propose a potential association between blepharospasm and pontine capillary telangiectasia. © 2012 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.

  9. Synthesis of bio-additives: transesterification of ethyl acetate with glycerol using homogeneous or heterogeneous acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Bruno A.; Pereira, Vera Lucia P., E-mail: patrocinio@nppn.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Ciencias da Saude. Nucleo de Pesquisas de Produtos Naturais

    2013-01-15

    A new catalytic route with potential practical interest to sustainable production of bioadditives from glycerol is described. Ethyl acetate was transesterified with glycerol, in the ratio glycerol:EtOAc 1:10, at 25 or 90 deg C using 0.1 equiv.of H{sub 2}SO{sub 4} or TsOH, as homogeneous catalysts. H{sub 2}SO{sub 4} led to the total glycerol consumption in 2 h. In the equilibrium, attained in 9 h, 100% yield of a diacetin:triacetin (55:45) mixture was formed. Using Amberlyst Registered-Sign 15 dry and Amberlyst Registered-Sign 16 wet in 1:30 glycerol:EtOAc ratio and reflux at 90 Degree-Sign C the total glycerol consumption was achieved in 2 and 10h, respectively. The lower reactivity of Amberlyst-16 wet was explained in terms of deactivation of acid sites and decrease in glycerol diffusion to the inner resin pores, both factors caused by adsorbed water. The kinetics of glycerol transformation and product distribution in the equilibrium in relation to the H{sub 2}SO{sub 4}, Amberlyst-15 (dry) and Amberlyst-16 (wet) catalyzed reactions were measured. (author)

  10. One-step selective synthesis of branched 1-O-alkyl-glycerol/diglycerol monoethers by catalytic reductive alkylation of ketones

    Institute of Scientific and Technical Information of China (English)

    DAYOUB; Wissam; LEMAIRE; Marc

    2010-01-01

    Branched 1-O-alkyl glycerol and diglycerol monoethers were obtained in good yields and high selectivity by a straightforward catalytic reductive alkylation of glycerol with relevant ketones in the presence of 0.5 mol% of Pd/C under 10 bar of hydrogen pressure using a Brφnsted acid as the co-catalyst.

  11. CHANGES OF GLYCEROL CONTENT IN DIAPAUSE LARVAEOF THE ORANGE WHEAT BLOSSOM MIDGE, SITODIPLOSIS MOSELLANA (GEHIN) IN VARIOUS SEASONS

    Institute of Scientific and Technical Information of China (English)

    Jun-xiangWu; FengYuan

    2004-01-01

    The glycerol contents in diapause larvae of the orange wheat blossom midge, Sitodiplosis mosellana (Gehin), collected from various seasons, were measured. The results showed that there was less glycerol content in larvae during living on the wheat head. Content of glycerol began to increase significantly when the larvae left the wheat head and entered the soil. A change trend of upper- lower- upper- lower in larvae glycerol contents during diapause in soil was observed from June to April of next year. More glycerol could be examined in larvae collected in summer and winter than in spring and autumn. There was not more glycerol in cocooned larvae than that in non-cocooned larvae during various seasons from the point of statistics. Comparing the glycerol content of larvae being diapause in the first year with that of larvae in the second year, there was yet no obvious difference when larvae were collected in the same season belonged to different years. Therefore, it is shown that the content of glycerol in larvae of the wheat midge in diapause is affected mainly by the seasons or diapause intensity.

  12. Recombinant oxalate decarboxylase: enhancement of a hybrid catalytic cascade for the complete electro-oxidation of glycerol.

    Science.gov (United States)

    Abdellaoui, Sofiene; Hickey, David P; Stephens, Andrew R; Minteer, Shelley D

    2015-10-01

    The complete electro-oxidation of glycerol to CO2 is performed through an oxidation cascade using a hybrid catalytic system combining a recombinant enzyme, oxalate decarboxylase from Bacillus subtilis, and an organic oxidation catalyst, 4-amino-TEMPO. This system is capable of electrochemically oxidizing glycerol at a carbon electrode collecting all 14 electrons per molecule. PMID:26271633

  13. Valorisation of crude glycerol through biological conversion into bioplastics and biofuels in the frame of an FP7 project

    DEFF Research Database (Denmark)

    Varrone, Cristiano; Gavala, Hariklia N.

    a very low value, due to the impurities and contaminants, and the purification of glycerol is not a viable option for the biodiesel industry anymore. In fact, crude glycerol is usually contaminated with water, methanol, soap, oil, and other compounds deriving from the transesterification process...

  14. Microbial fed-batch production of 1,3-propanediol using raw glycerol with suspended and immobilized Klebsiella pneumoniae.

    Science.gov (United States)

    Jun, Sun-Ae; Moon, Chuloo; Kang, Cheol-Hee; Kong, Sean W; Sang, Byoung-In; Um, Youngsoon

    2010-05-01

    The production of 1,3-propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM 4799 using raw glycerol without purification obtained from a biodiesel production process. Fed-batch cultures with suspended cells revealed that 1,3-PD production was more effective when utilizing raw glycerol than pure glycerol (productivity after 47 h of fermentation, 0.84 g L(-1) 1 h(-1) versus 1.51 g L(-1) h(-1) with pure and raw glycerol,respectively). In addition, more than 80 g/L of 1,3-PD was produced using raw glycerol;this is the highest 1,3-PD concentration reported thus far for K. pneumoniae using raw glycerol. Repeated fed-batch fermentation with cell immobilization in a fixed-bed reactor was performed to enhance 1,3-PD production. Production of 1,3-PD increased with the cycle number (1.06 g L(-1) h(-1) versus 1.61 g L(-1) h(-1) at the first and fourth cycle, respectively)due to successful cell immobilization. During 46 cycles of fed-batch fermentation taking place over 1,460 h, a stable and reproducible 1,3-PD production performance was observed with both pure and raw glycerol. Based on our results, repeated fed batch with immobilized cells is an efficient fermentor configuration, and raw glycerol can be utilized to produce 1,3-PD without inhibitory effects caused by accumulated impurities.

  15. Gpd1 and Gpd2 fine-tuning for sustainable reduction of glycerol formation in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Hubmann, Georg; Guillouet, Stephane; Nevoigt, Elke

    2011-01-01

    Gpd1 and Gpd2 are the two isoforms of glycerol 3-phosphate dehydrogenase (GPDH), which is the rate-controlling enzyme of glycerol formation in Saccharomyces cerevisiae. The two isoenzymes play crucial roles in osmoregulation and redox balancing. Past approaches to increase ethanol yield at the cost

  16. Pore capillary pressure and saturation of methane hydrate bearing sediments

    Institute of Scientific and Technical Information of China (English)

    SUN Shicai; LIU Changling; YE Yuguang; LIU Yufeng

    2014-01-01

    To better understand the relationship between the pore capillary pressure and hydrate saturation in sedi-ments, a new method was proposed. First, the phase equilibria of methane hydrate in fine-grained silica sands were measured. As to the equilibrium data, the pore capillary pressure and saturation of methane hydrate were calculated. The results showed that the phase equilibria of methane hydrates in fine-grained silica sands changed due to the depressed activity of pore water caused by the surface group and negatively charged characteristic of silica particles as well as the capillary pressure in small pores together. The capil-lary pressure increased with the increase of methane hydrate saturation due to the decrease of the available pore space. However, the capillary-saturation relationship could not yet be described quantitatively because of the stochastic habit of hydrate growth.

  17. Lattice-Boltzmann modeling of experimental fluid displacement patterns, interfacial area and capillary trapped CO2

    Science.gov (United States)

    Porter, M. L.; Kang, Q.; Tarimala, S.; Abdel-Fattah, A.; Backhaus, S.; Carey, J. W.

    2010-12-01

    Successful sequestration of CO2 into deep saline aquifers presents an enormous challenge that requires fundamental understanding of reactive-multiphase flow and transport across many temporal and spatial scales. Of critical importance is accurately predicting the efficiency of CO2 trapping mechanisms. At the pore scale (e.g., microns to millimeters) the interfacial area between CO2 and brine, as well as CO2 and the solid phase, directly influences the amount of CO2 trapped due to capillary forces, dissolution and mineral precipitation. In this work, we model immiscible displacement micromodel experiments using the lattice-Boltzmann (LB) method. We focus on quantifying interfacial area as a function of capillary numbers and viscosity ratios typically encountered in CO2 sequestration operations. We show that the LB model adequately predicts the steady-state experimental flow patterns and interfacial area measurements. Based on the steady-state agreement, we use the LB model to investigate interfacial dynamics (e.g., fluid-fluid interfacial velocity and the rate of production of fluid-fluid interfacial area). In addition, we quantify the amount of interfacial area and the interfacial dynamics associated with the capillary trapped nonwetting phase. This is expected to be important for predicting the amount of nonwetting phase subsequently trapped due to dissolution and mineral precipitation.

  18. Quality criterion to optimize separations in capillary electrophoresis: Application to the analysis of harmala alkaloids.

    Science.gov (United States)

    Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G

    2016-08-19

    In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model. PMID:27443250

  19. Capillary Corner Flows With Partial and Nonwetting Fluids

    Science.gov (United States)

    Bolleddula, D. A.; Weislogel, M. M.

    2009-01-01

    Capillary flow in containers or conduits with interior corners are common place in nature and industry. The majority of investigations addressing such flows solve the problem numerically in terms of a friction factor for flows along corners with contact angles below the Concus-Finn critical wetting condition for the particular conduit geometry of interest. This research effort provides missing numerical data for the flow resistance function F(sub i) for partially and nonwetting systems above the Concus-Finn condition. In such cases the fluid spontaneously de-wets the interior corner and often retracts into corner-bound drops. A banded numerical coefficient is desirable for further analysis and is achieved by careful selection of length scales x(sub s) and y(sub s) to nondimensionalize the problem. The optimal scaling is found to be identical to the wetting scaling, namely x(sub s) = H and y(sub s) = Htan (alpha), where H is the height from the corner to the free surface and a is the corner half-angle. Employing this scaling produces a relatively weakly varying flow resistance F(sub i) and for subsequent analyses is treated as a constant. Example solutions to steady and transient flow problems are provided that illustrate applications of this result.

  20. Efficient conversion of crude glycerol from various industrial wastes into single cell oil by yeast Yarrowia lipolytica.

    Science.gov (United States)

    Dobrowolski, Adam; Mituła, Paweł; Rymowicz, Waldemar; Mirończuk, Aleksandra M

    2016-05-01

    In this study, crude glycerol from various industries was used to produce lipids via wild type Yarrowia lipolytica A101. We tested samples without any prior purification from five different waste products; each contained various concentrations of glycerol (42-87%) as the sole carbon source. The best results for lipid production were obtained for medium containing glycerol from fat saponification. This reached 1.69gL(-1) (25% of total cell dry weight) with a biomass yield of 0.17gg(-1) in the flasks experiment. The batch cultivation in a bioreactor resulted in enhanced lipid production-it achieved 4.72gL(-1) with a biomass yield 0.21gg(-1). Moreover, the properly selected batch of crude glycerol provides a defined fatty acid composition. In summary, this paper shows that crude glycerol from soap production could be efficiently converted to single cell oil without any prior purification. PMID:26890799