Simulation of elution profiles in liquid chromatography - II: Investigation of injection volume overload under gradient elution conditions applied to second dimension separations in two-dimensional liquid chromatography.

PubMed

Stoll, Dwight R; Sajulga, Ray W; Voigt, Bryan N; Larson, Eli J; Jeong, Lena N; Rutan, Sarah C

2017-11-10

An important research direction in the continued development of two-dimensional liquid chromatography (2D-LC) is to improve the detection sensitivity of the method. This is especially important in applications where injection of large volumes of effluent from the first dimension ( 1 D) column into the second dimension ( 2 D) column leads to severe 2 D peak broadening and peak shape distortion. For example, this is common when coupling two reversed-phase columns and the organic solvent content of the 1 D mobile phase overwhelms the 2 D column with each injection of 1 D effluent, leading to low resolution in the second dimension. In a previous study we validated a simulation approach based on the Craig distribution model and adapted from the work of Czok and Guiochon [1] that enabled accurate simulation of simple isocratic and gradient separations with very small injection volumes, and isocratic separations with mismatched injection and mobile phase solvents [2]. In the present study we have extended this simulation approach to simulate separations relevant to 2D-LC. Specifically, we have focused on simulating 2 D separations where gradient elution conditions are used, there is mismatch between the sample solvent and the starting point in the gradient elution program, injection volumes approach or even exceed the dead volume of the 2 D column, and the extent of sample loop filling is varied. To validate this simulation we have compared results from simulations and experiments for 101 different conditions, including variation in injection volume (0.4-80μL), loop filling level (25-100%), and degree of mismatch between sample organic solvent and the starting point in the gradient elution program (-20 to +20% ACN). We find that that the simulation is accurate enough (median errors in retention time and peak width of -1.0 and -4.9%, without corrections for extra-column dispersion) to be useful in guiding optimization of 2D-LC separations. However, this requires that real injection profiles obtained from 2D-LC interface valves are used to simulate the introduction of samples into the 2 D column. These profiles are highly asymmetric - simulation using simple rectangular pulses leads to peak widths that are far too narrow under many conditions. We believe the simulation approach developed here will be useful for addressing practical questions in the development of 2D-LC methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Modified electrokinetic sample injection method in chromatography and electrophoresis analysis

DOEpatents

Davidson, J. Courtney; Balch, Joseph W.

2001-01-01

A sample injection method for horizontal configured multiple chromatography or electrophoresis units, each containing a number of separation/analysis channels, that enables efficient introduction of analyte samples. This method for loading when taken in conjunction with horizontal microchannels allows much reduced sample volumes and a means of sample stacking to greatly reduce the concentration of the sample. This reduction in the amount of sample can lead to great cost savings in sample preparation, particularly in massively parallel applications such as DNA sequencing. The essence of this method is in preparation of the input of the separation channel, the physical sample introduction, and subsequent removal of excess material. By this method, sample volumes of 100 nanoliter to 2 microliters have been used successfully, compared to the typical 5 microliters of sample required by the prior separation/analysis method.

Electrochemical attosyringe.

PubMed

Laforge, François O; Carpino, James; Rotenberg, Susan A; Mirkin, Michael V

2007-07-17

The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10(-18) to 10(-12) liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems.

Electrochemical attosyringe

PubMed Central

Laforge, François O.; Carpino, James; Rotenberg, Susan A.; Mirkin, Michael V.

2007-01-01

The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10−18 to 10−12 liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems. PMID:17620612

Data on subsurface storage of liquid waste near Pensacola, Florida, 1963-1980

USGS Publications Warehouse

Hull, R.W.; Martin, J.B.

1982-01-01

Since 1963, when industrial waste was first injected into the subsurface in northwest Florida, considerable data have been collected relating to the geochemistry of subsurface waste storage. This report presents hydrogeologic data on two subsurface waste storage. This report presents hydrogeologic data on two subsurface storage systems near Pensacola, Fla., which inject liquid industrial waste through deep wells into a saline aquifer. Injection sites are described giving a history of well construction, injection, and testing; geologic data from cores and grab samples; hydrographs of injection rates, volume, pressure, and water levels; and chemical and physical data from water-quality samples collected from injection and monitor wells. (USGS)

Measurement of lung fluid volumes and albumin exclusion in sheep

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pou, N.A.; Roselli, R.J.; Parker, R.E.

1989-10-01

A radioactive tracer technique was used to determine interstitial diethylenetriaminepentaacetic acid (DTPA) and albumin distribution volume in sheep lungs. {sup 125}I- and/or {sup 131}I-labeled albumin were injected intravenously and allowed to equilibrate for 24 h. {sup 99m}Tc-labeled DTPA and {sup 51}Cr-labeled erythrocytes were injected and allowed to equilibrate (2 h and 15 min, respectively) before a lethal dose of thiamylal sodium. Two biopsies (1-3 g) were taken from each lung and the remaining tissue was homogenized for wet-to-dry lung weight and volume calculations. Estimates of distribution volumes from whole lung homogenized samples were statistically smaller than biopsy samples for extravascularmore » water, interstitial {sup 99m}Tc-DTPA, and interstitial albumin. The mean fraction of the interstitium (Fe), which excludes albumin, was 0.68 +/- 0.04 for whole lung samples compared with 0.62 +/- 0.03 for biopsy samples. Hematocrit may explain the consistent difference. To make the Fe for biopsy samples match that for homogenized samples, a mean hematocrit, which was 82% of large vessel hematocrit, was required. Excluded volume fraction for exogenous sheep albumin was compared with that of exogenous human albumin in two sheep, and no difference was found at 24 h.« less

Determination of mercury by multisyringe flow injection system with cold-vapor atomic absorption spectrometry.

PubMed

Leal, L O; Elsholz, O; Forteza, R; Cerdà, V

2006-07-28

A new software-controlled time-based multisyringe flow injection system for mercury determination by cold-vapor atomic absorption spectrometry is proposed. Precise known volumes of sample, reducing agent (1.1% SnCl2 in 3% HCl) and carrier (3% HCl) are dispensed into a gas-liquid separation cell with a multisyringe burette coupled with one three-way solenoid valve. An argon flow delivers the reduced mercury to the spectrometer. The optimization of the system was carried out testing reaction coils and gas-liquid separators of different design as well as changing parameters, such as sample and reagents volumes, reagent concentrations and carrier gas flow rate, among others. The analytical curves were obtained within the range 50-5000 ng L(-1). The detection limit (3sigma(b)/S) achieved is 5 ng L(-1). The relative standard deviation (R.S.D.) was 1.4%, evaluated from 16 successive injections of 250 ng L(-1) Hg standard solution. The injection and sample throughput per hour were 44 and 11, respectively. This technique was validated by means of solid and water reference materials with good agreement with the certified values and was successfully applied to fish samples.

Design and characterization of poly(dimethylsiloxane)-based valves for interfacing continuous-flow sampling to microchip electrophoresis.

PubMed

Li, Michelle W; Huynh, Bryan H; Hulvey, Matthew K; Lunte, Susan M; Martin, R Scott

2006-02-15

This work describes the fabrication and evaluation of a poly(dimethyl)siloxane (PDMS)-based device that enables the discrete injection of a sample plug from a continuous-flow stream into a microchannel for subsequent analysis by electrophoresis. Devices were fabricated by aligning valving and flow channel layers followed by plasma sealing the combined layers onto a glass plate that contained fittings for the introduction of liquid sample and nitrogen gas. The design incorporates a reduced-volume pneumatic valve that actuates (on the order of hundreds of milliseconds) to allow analyte from a continuously flowing sampling channel to be injected into a separation channel for electrophoresis. The injector design was optimized to include a pushback channel to flush away stagnant sample associated with the injector dead volume. The effect of the valve actuation time, the pushback voltage, and the sampling stream flow rate on the performance of the device was characterized. Using the optimized design and an injection frequency of 0.64 Hz showed that the injection process is reproducible (RSD of 1.77%, n = 15). Concentration change experiments using fluorescein as the analyte showed that the device could achieve a lag time as small as 14 s. Finally, to demonstrate the potential uses of this device, the microchip was coupled to a microdialysis probe to monitor a concentration change and sample a fluorescein dye mixture.

Electrokinetic Sample Preconcentration and Hydrodynamic Sample Injection for Microchip Electrophoresis Using a Pneumatic Microvalve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cong, Yongzheng; Katipamula, Shanta; Geng, Tao

2016-02-01

A microfluidic platform was developed to perform online electrokinetic sample preconcentration and rapid hydrodynamic sample injection for electrophoresis using a single microvalve. The PDMS microchip consists of a separation channel, a side channel for sample introduction, and a control channel which is used as a pneumatic microvalve aligned at the intersection of the two flow channels. The closed microvalve, created by multilayer soft lithography, can serve as a preconcentrator under an applied electric potential, enabling current to pass through while blocking bulk flow. Once analytes are concentrated, the valve is briefly opened and the stacked sample is pressure injected intomore » the separation channel for electrophoretic separation. Fluorescently labeled peptides were enriched by a factor of ~450 in 230 s. The performance of the platform was validated by the online preconcentration, injection and electrophoretic separation of fluorescently labeled peptides. This method enables both rapid analyte concentration and controlled injection volume for high sensitivity, high resolution capillary electrophoresis.« less

Dispersion of a Nanoliter Bolus in Microfluidic Co-Flow.

PubMed

Conway, A J; Saadi, W M; Sinatra, F L; Kowalski, G; Larson, D; Fiering, J

2014-03-01

Microfluidic systems enable reactions and assays on the scale of nanoliters. However, at this scale nonuniformities in sample delivery become significant. To determine the fundamental minimum sample volume required for a particular device, a detailed understanding of mass transport is required. Co-flowing laminar streams are widely used in many devices, but typically only in the steady-state. Because establishing the co-flow steady-state consumes excess sample volume and time, there is a benefit to operating devices in the transient state, which predominates as the volume of the co-flow reactor decreases. Analysis of the co-flow transient has been neglected thus far. In this work we describe the fabrication of a pneumatically controlled microfluidic injector constructed to inject a discrete 50nL bolus into one side of a two-stream co-flow reactor. Using dye for image analysis, injections were performed at a range of flow rates from 0.5-10μL/min, and for comparison we collected the co-flow steady-state data for this range. The results of the image analysis were also compared against theory and simulations for device validation. For evaluation, we established a metric that indicates how well the mass distribution in the bolus injection approximates steady-state co-flow. Using such analysis, transient-state injections can approximate steady-state conditions within predefined errors, allowing straight forward measurements to be performed with reduced reagent consumption.

Electrokinetic sample preconcentration and hydrodynamic sample injection for microchip electrophoresis using a pneumatic microvalve.

PubMed

Cong, Yongzheng; Katipamula, Shanta; Geng, Tao; Prost, Spencer A; Tang, Keqi; Kelly, Ryan T

2016-02-01

A microfluidic platform was developed to perform online electrokinetic sample preconcentration and rapid hydrodynamic sample injection for zone electrophoresis using a single microvalve. The polydimethylsiloxane microchip comprises a separation channel, a side channel for sample introduction, and a control channel which is used as a pneumatic microvalve aligned at the intersection of the two flow channels. The closed microvalve, created by multilayer soft lithography, serves as a nanochannel preconcentrator under an applied electric potential, enabling current to pass through while preventing bulk flow. Once analytes are concentrated, the valve is briefly opened and the stacked sample is pressure injected into the separation channel for electrophoretic separation. Fluorescently labeled peptides were enriched by a factor of ∼450 in 230 s. This method enables both rapid analyte concentration and controlled injection volume for high sensitivity, high-resolution CE. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combined Falling Drop/Open Port Sampling Interface System for Automated Flow Injection Mass Spectrometry

DOE PAGES

Van Berkel, Gary J.; Kertesz, Vilmos; Orcutt, Matt; ...

2017-11-07

The aim of this work was to demonstrate and to evaluate the analytical performance of a combined falling drop/open port sampling interface (OPSI) system as a simple noncontact, no-carryover, automated system for flow injection analysis with mass spectrometry. The falling sample drops were introduced into the OPSI using a widely available autosampler platform utilizing low cost disposable pipet tips and conventional disposable microtiter well plates. The volume of the drops that fell onto the OPSI was in the 7–15 μL range with an injected sample volume of several hundred nanoliters. Sample drop height, positioning of the internal capillary on themore » sampling end of the probe, and carrier solvent flow rate were optimized for maximum signal. Sample throughput, signal reproducibility, matrix effects, and quantitative analysis capability of the system were established using the drug molecule propranolol and its isotope labeled internal standard in water, unprocessed river water and two commercially available buffer matrices. A sample-to-sample throughput of ~45 s with a ~4.5 s base-to-base flow injection peak profile was obtained in these experiments. In addition, quantitation with minimally processed rat plasma samples was demonstrated with three different statin drugs (atorvastatin, rosuvastatin, and fluvastatin). Direct characterization capability of unprocessed samples was demonstrated by the analysis of neat vegetable oils. Employing the autosampler system for spatially resolved liquid extraction surface sampling exemplified by the analysis of propranolol and its hydroxypropranolol glucuronide phase II metabolites from a rat thin tissue section was also illustrated.« less

Combined Falling Drop/Open Port Sampling Interface System for Automated Flow Injection Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J.; Kertesz, Vilmos; Orcutt, Matt

The aim of this work was to demonstrate and to evaluate the analytical performance of a combined falling drop/open port sampling interface (OPSI) system as a simple noncontact, no-carryover, automated system for flow injection analysis with mass spectrometry. The falling sample drops were introduced into the OPSI using a widely available autosampler platform utilizing low cost disposable pipet tips and conventional disposable microtiter well plates. The volume of the drops that fell onto the OPSI was in the 7–15 μL range with an injected sample volume of several hundred nanoliters. Sample drop height, positioning of the internal capillary on themore » sampling end of the probe, and carrier solvent flow rate were optimized for maximum signal. Sample throughput, signal reproducibility, matrix effects, and quantitative analysis capability of the system were established using the drug molecule propranolol and its isotope labeled internal standard in water, unprocessed river water and two commercially available buffer matrices. A sample-to-sample throughput of ~45 s with a ~4.5 s base-to-base flow injection peak profile was obtained in these experiments. In addition, quantitation with minimally processed rat plasma samples was demonstrated with three different statin drugs (atorvastatin, rosuvastatin, and fluvastatin). Direct characterization capability of unprocessed samples was demonstrated by the analysis of neat vegetable oils. Employing the autosampler system for spatially resolved liquid extraction surface sampling exemplified by the analysis of propranolol and its hydroxypropranolol glucuronide phase II metabolites from a rat thin tissue section was also illustrated.« less

A systematic investigation of sample diluents in modern supercritical fluid chromatography.

PubMed

Desfontaine, Vincent; Tarafder, Abhijit; Hill, Jason; Fairchild, Jacob; Grand-Guillaume Perrenoud, Alexandre; Veuthey, Jean-Luc; Guillarme, Davy

2017-08-18

This paper focuses on the possibility to inject large volumes (up to 10μL) in ultra-high performance supercritical fluid chromatography (UHPSFC) under generic gradient conditions. Several injection and method parameters have been individually evaluated (i.e. analyte concentration, injection volume, initial percentage of co-solvent in the gradient, nature of the weak needle wash solvent, nature of the sample diluent, nature of the column and of the analyte). The most critical parameters were further investigated using in a multivariate approach. The overall results suggested that several aprotic solvents including methyl tert-butyl ether (MTBE), dichloromethane, acetonitrile or cyclopentyl methyl ether (CPME) were well adapted for the injection of large volume in UHPSFC, while MeOH was generally the worst alternative. However, the nature of the stationary phase also had a strong impact and some of these diluents did not perform equally on each column. This was due to the existence of a competition in the adsorption of the analyte and the diluent on the stationary phase. This observation introduced the idea that the sample diluent should not only be chosen according to the analyte but also to the column chemistry to limit the interactions between the diluent and the ligands. Other important characteristics of the "ideal" SFC sample diluent were finally highlighted. Aprotic solvents with low viscosity are preferable to avoid strong solvent effects and viscous fingering, respectively. In the end, the authors suggest that the choice of the sample diluent should be part of the method development, as a function of the analyte and the selected stationary phase. Copyright © 2017 Elsevier B.V. All rights reserved.

Measuring Compartment Size and Gas Solubility in Marine Mammals

DTIC Science & Technology

2014-09-30

analyzed by gas chromatography . Injection of the sample into the gas chromatograph is done using a sample loop to minimize volume injection error. We...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Measuring Compartment Size and Gas Solubility in Marine...study is to develop methods to estimate marine mammal tissue compartment sizes, and tissue gas solubility. We aim to improve the data available for

Liquid microjunction surface sampling probe fluid dynamics: Characterization and application of an analyte plug formation operational mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

ElNaggar, Mariam S.; Van Berkel, Gary J.

2011-08-10

The recently discovered sample plug formation and injection operational mode of a continuous flow, coaxial tube geometry, liquid microjunction surface sampling probe (LMJ-SSP) (J. Am. Soc. Mass Spectrom, 2011) was further characterized and applied for concentration and mixing of analyte extracted from multiple areas on a surface and for nanoliter-scale chemical reactions of sampled material. A transparent LMJ-SSP was constructed and colored analytes were used so that the surface sampling process, plug formation, and the chemical reactions could be visually monitored at the sampling end of the probe before being analyzed by mass spectrometry of the injected sample plug. Injectionmore » plug peak widths were consistent for plug hold times as long as the 8 minute maximum attempted (RSD below 1.5%). Furthermore, integrated injection peak signals were not significantly different for the range of hold times investigated. The ability to extract and completely mix individual samples within a fixed volume at the sampling end of the probe was demonstrated and a linear mass spectral response to the number of equivalent analyte spots sampled was observed. Lastly, using the color and mass changing chemical reduction of the redox dye 2,6-dichlorophenol-indophenol with ascorbic acid, the ability to sample, concentrate, and efficiently run reactions within the same plug volume within the probe was demonstrated.« less

Separation and determination of estrogen in the water environment by high performance liquid chromatography-fourier transform infrared spectroscopy

PubMed Central

Zheng, Bei; Li, Wentao; Li, Hongyan; Liu, Lin; Lei, Pei; Ge, Xiaopeng; Yu, Zhiyong; Zhou, Yiqi

2016-01-01

The components for connecting high-performance liquid chromatography (HPLC) with Fourier-transform infrared spectroscopy (FTIR) were investigated to determine estrogen in the water environment, including heating for atomization, solvent removal, sample deposition, drive control, spectrum collection, chip swap, cleaning and drying. Results showed that when the atomization temperature was increased to 388 K, the interference of mobile phase components (methanol, H2O, acetonitrile, and NaH2PO4) were completely removed in the IR measurement of estrogen, with 0.999 of similarity between IR spectra obtained after separation and corresponding to the standard IR spectra. In experiments with varying HPLC injection volumes, high similarity for IR spectra was obtained at 20 ul injection volume at 0.01 mg/L BPA while a useful IR spectrum for 10 ng/L BPA was obtained at 80 ul injection volume. In addition, estrogen concentrations in the natural water samples were calculated semi-quantitatively from the peak intensities of IR spectrum in the mid-infrared region. PMID:27577974

Separation and determination of estrogen in the water environment by high performance liquid chromatography-fourier transform infrared spectroscopy

NASA Astrophysics Data System (ADS)

Zheng, Bei; Li, Wentao; Li, Hongyan; Liu, Lin; Lei, Pei; Ge, Xiaopeng; Yu, Zhiyong; Zhou, Yiqi

2016-08-01

The components for connecting high-performance liquid chromatography (HPLC) with Fourier-transform infrared spectroscopy (FTIR) were investigated to determine estrogen in the water environment, including heating for atomization, solvent removal, sample deposition, drive control, spectrum collection, chip swap, cleaning and drying. Results showed that when the atomization temperature was increased to 388 K, the interference of mobile phase components (methanol, H2O, acetonitrile, and NaH2PO4) were completely removed in the IR measurement of estrogen, with 0.999 of similarity between IR spectra obtained after separation and corresponding to the standard IR spectra. In experiments with varying HPLC injection volumes, high similarity for IR spectra was obtained at 20 ul injection volume at 0.01 mg/L BPA while a useful IR spectrum for 10 ng/L BPA was obtained at 80 ul injection volume. In addition, estrogen concentrations in the natural water samples were calculated semi-quantitatively from the peak intensities of IR spectrum in the mid-infrared region.

Dispersive liquid-liquid microextraction for the determination of nitrophenols in soils by microvial insert large volume injection-gas chromatography-mass spectrometry.

PubMed

Cacho, J I; Campillo, N; Viñas, P; Hernández-Córdoba, M

2016-07-22

A rapid and sensitive procedure for the determination of six NPs in soils by gas chromatography and mass spectrometry (GC-MS) is proposed. Ultrasound assisted extraction (UAE) is used for NP extraction from soil matrices to an organic solvent, while the environmentally friendly technique dispersive liquid-liquid microextraction (DLLME) is used for the preconcentration of the resulting UAE extracts. NPs were derivatized by applying an "in-situ" acetylation procedure, before being injected into the GC-MS system using microvial insert large volume injection (LVI). Several parameters affecting UAE, DLLME, derivatization and injection steps were investigated. The optimized procedure provided recoveries of 86-111% from spiked samples. Precision values of the procedure (expressed as relative standard deviation, RSD) lower than 12%, and limits of quantification ranging from 1.3 to 2.6ngg(-1), depending on the compound, were obtained. Twenty soil samples, obtained from military, industrial and agricultural areas, were analyzed by the proposed method. Two of the analytes were quantified in two of the samples obtained from industrial areas, at concentrations in the 4.8-9.6ngg(-1) range. Copyright © 2016 Elsevier B.V. All rights reserved.

High-accuracy measurements of N2O concentration and site-specific nitrogen isotopes in small or high concentration samples

NASA Astrophysics Data System (ADS)

Palmer, M. R.; Arata, C.; Huang, K.

2014-12-01

Nitrous oxide (N2O) gas is among the major contributors to global warming and ozone depletion in stratosphere. Quantitative estimate of N­2O production in various pathways and N­2O fluxes across different reservoirs is the key to understanding the role of N­2O in the global change. To achieve this goal, accurate and concurrent measurement of both N2O concentration ([N2O]) and its site-specific isotopic composition (SP-δ15N), namely δ15Nα and δ15Nβ, is desired. Recent developments in Cavity Ring-Down Spectroscopy (CRDS) have enabled high precision measurements of [N2O] and SP-δ15N of a continuous gas flow. However, many N­­2O samples are discrete with limited volume (< 500 ml), and/or high [N2O] (> 2 ppm), and are not suitable for direct measurements by CRDS. Here we present results of a Small Sample Isotope Module 2 (SSIM2) which is coupled to and automatically coordinated with a Picarro isotopic N2O CRDS analyzer to handle and measure high concentration and/or small volume samples. The SSIM2 requires 20 ml of sample per analysis, and transfers the sample to the CRDS for high precision measurement. When the sample injection is < 20 ml, a zero gas is optionally filled to make up the volume. We used the SSIM2 to dilute high [N2O] samples and < 20 ml samples, and tested the effect of dilution on the measured SP-δ15N. In addition, we employed and tested a newly developed double injection method for samples adequate for two 20 ml injections. After the SSIM2 and the CRDS cavity was primed with the first injection, the second injection, which has negligible dilution of the sample, can be accurately measured for both [N2O] and SP-δ15N. Results of these experiments indicate that the precision of SSIM2-CRDS is similar to that of the continuous measurements using the CRDS alone, and that dilution has minimal effect on SP-δ15N, as along as the [N2O] is > 300 ppb after dilution. Overall, the precision of SP-δ15N measured using the SSIM2 is < 0.5 ‰.

Analysis of chlorophenoxy acid herbicides in water by large-volume on-line derivatization and gas chromatography-mass spectrometry.

PubMed

Ding, W H; Liu, C H; Yeh, S P

2000-10-27

This work presents a modified method to analyze chlorophenoxy acid herbicides in water samples. The herbicides 2,4-D (2,4-dichlorophenoxyacetic acid). Silvex (2,4,5-trichlorophenoxypropionic acid) and 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) were used to evaluate the method. The method involves extraction of samples by a graphitized carbon black cartridge, and on-line derivatization in the GC injection port using a large-volume (10-20 microl) direct sample introduction (DSI) device with tetraalkylammonium salts. The analytes were then identified and quantitated by ion-trap gas chromatography-mass spectrometry. The large-volume DSI injection-port derivatization technique provides sensitivity, fast and reproducible results for chlorophenoxy acid herbicides residues, to quantitation at 0.1 to 0.2 microg/l in 500-ml water samples. An enhanced characteristic mass chromatogram of molecular ions of butylated chlorophenoxy acid herbicides with a significant chlorine isotope pattern by electron impact ionization MS allows us to determine herbicides residues at trace levels in aqueous samples. Recovery of the herbicide residues in spiked various water samples ranged from 70 to 99% while RSDs ranged from 1 to 13%.

Determination of acrylamide in drinking water by large-volume direct injection and ion-exclusion chromatography-mass spectrometry.

PubMed

Cavalli, S; Polesello, S; Saccani, G

2004-06-11

Acrylamide, a known neurotoxin and putative human carcinogen, has been included among the substances to be monitored in drinking water according to the European Union Directive 98/83 on potable water. This paper reports a new method based on the combination of ion-exclusion chromatographic separation and MS detection. Samples of drinking water have been directly injected in the microbore ICE-AS1 column and detected in the selected-ion monitoring mode by a single quadrupole system with electrospray ionization. Chromatographic conditions, such as eluent composition and flow rate, have been optimized by a central composite design experiment. Statistical analysis of data showed that the amount of acetonitrile fraction in the eluent mixture, composed by acetonitrile and formic acid solution, is the variable that most influences retention of the acrylamide peak. After optimization of MS detection parameters, this method has been validated for spiked drinking water samples. The effect of large-volume injection (up to 500 microl) has been also explored. Linearity was evaluated from 0.5 to 5 microg l(-1). Repeatability, expressed as R.S.D., was 16 and 12% at 0.5 and 1 microg l(-1) respectively. The limit of detection was 0.20 ppb with 500 microl injection volume.

Analysis of polycyclic aromatic hydrocarbons in water and beverages using membrane-assisted solvent extraction in combination with large volume injection-gas chromatography-mass spectrometric detection.

PubMed

Rodil, Rosario; Schellin, Manuela; Popp, Peter

2007-09-07

Membrane-assisted solvent extraction (MASE) in combination with large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) was applied for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. The MASE conditions were optimized for achieving high enrichment of the analytes from aqueous samples, in terms of extraction conditions (shaking speed, extraction temperature and time), extraction solvent and composition (ionic strength, sample pH and presence of organic solvent). Parameters like linearity and reproducibility of the procedure were determined. The extraction efficiency was above 65% for all the analytes and the relative standard deviation (RSD) for five consecutive extractions ranged from 6 to 18%. At optimized conditions detection limits at the ng/L level were achieved. The effectiveness of the method was tested by analyzing real samples, such as river water, apple juice, red wine and milk.

Quantification of a maximum injection volume of CO2 to avert geomechanical perturbations using a compositional fluid flow reservoir simulator

NASA Astrophysics Data System (ADS)

Jung, Hojung; Singh, Gurpreet; Espinoza, D. Nicolas; Wheeler, Mary F.

2018-02-01

Subsurface CO2 injection and storage alters formation pressure. Changes of pore pressure may result in fault reactivation and hydraulic fracturing if the pressure exceeds the corresponding thresholds. Most simulation models predict such thresholds utilizing relatively homogeneous reservoir rock models and do not account for CO2 dissolution in the brine phase to calculate pore pressure evolution. This study presents an estimation of reservoir capacity in terms of allowable injection volume and rate utilizing the Frio CO2 injection site in the coast of the Gulf of Mexico as a case study. The work includes laboratory core testing, well-logging data analyses, and reservoir numerical simulation. We built a fine-scale reservoir model of the Frio pilot test in our in-house reservoir simulator IPARS (Integrated Parallel Accurate Reservoir Simulator). We first performed history matching of the pressure transient data of the Frio pilot test, and then used this history-matched reservoir model to investigate the effect of the CO2 dissolution into brine and predict the implications of larger CO2 injection volumes. Our simulation results -including CO2 dissolution- exhibited 33% lower pressure build-up relative to the simulation excluding dissolution. Capillary heterogeneity helps spread the CO2 plume and facilitate early breakthrough. Formation expansivity helps alleviate pore pressure build-up. Simulation results suggest that the injection schedule adopted during the actual pilot test very likely did not affect the mechanical integrity of the storage complex. Fault reactivation requires injection volumes of at least about sixty times larger than the actual injected volume at the same injection rate. Hydraulic fracturing necessitates much larger injection rates than the ones used in the Frio pilot test. Tested rock samples exhibit ductile deformation at in-situ effective stresses. Hence, we do not expect an increase of fault permeability in the Frio sand even in the presence of fault reactivation.

Small-Volume Injections: Evaluation of Volume Administration Deviation From Intended Injection Volumes.

PubMed

Muffly, Matthew K; Chen, Michael I; Claure, Rebecca E; Drover, David R; Efron, Bradley; Fitch, William L; Hammer, Gregory B

2017-10-01

In the perioperative period, anesthesiologists and postanesthesia care unit (PACU) nurses routinely prepare and administer small-volume IV injections, yet the accuracy of delivered medication volumes in this setting has not been described. In this ex vivo study, we sought to characterize the degree to which small-volume injections (≤0.5 mL) deviated from the intended injection volumes among a group of pediatric anesthesiologists and pediatric postanesthesia care unit (PACU) nurses. We hypothesized that as the intended injection volumes decreased, the deviation from those intended injection volumes would increase. Ten attending pediatric anesthesiologists and 10 pediatric PACU nurses each performed a series of 10 injections into a simulated patient IV setup. Practitioners used separate 1-mL tuberculin syringes with removable 18-gauge needles (Becton-Dickinson & Company, Franklin Lakes, NJ) to aspirate 5 different volumes (0.025, 0.05, 0.1, 0.25, and 0.5 mL) of 0.25 mM Lucifer Yellow (LY) fluorescent dye constituted in saline (Sigma Aldrich, St. Louis, MO) from a rubber-stoppered vial. Each participant then injected the specified volume of LY fluorescent dye via a 3-way stopcock into IV tubing with free-flowing 0.9% sodium chloride (10 mL/min). The injected volume of LY fluorescent dye and 0.9% sodium chloride then drained into a collection vial for laboratory analysis. Microplate fluorescence wavelength detection (Infinite M1000; Tecan, Mannedorf, Switzerland) was used to measure the fluorescence of the collected fluid. Administered injection volumes were calculated based on the fluorescence of the collected fluid using a calibration curve of known LY volumes and associated fluorescence.To determine whether deviation of the administered volumes from the intended injection volumes increased at lower injection volumes, we compared the proportional injection volume error (loge [administered volume/intended volume]) for each of the 5 injection volumes using a linear regression model. Analysis of variance was used to determine whether the absolute log proportional error differed by the intended injection volume. Interindividual and intraindividual deviation from the intended injection volume was also characterized. As the intended injection volumes decreased, the absolute log proportional injection volume error increased (analysis of variance, P < .0018). The exploratory analysis revealed no significant difference in the standard deviations of the log proportional errors for injection volumes between physicians and pediatric PACU nurses; however, the difference in absolute bias was significantly higher for nurses with a 2-sided significance of P = .03. Clinically significant dose variation occurs when injecting volumes ≤0.5 mL. Administering small volumes of medications may result in unintended medication administration errors.

COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270

EPA Science Inventory

Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste.

One SPE system, unique in the U.S., uses aut...

Gas-water-rock interactions in Frio Formation following CO2 injection: Implications for the storage of greenhouse gases in sedimentary basins

USGS Publications Warehouse

Kharaka, Yousif K.; Cole, David R.; Hovorka, Susan D.; Gunter, W.D.; Knauss, Kevin G.; Freifeild, Barry M.

2006-01-01

To investigate the potential for the geologic storage of CO2 in saline sedimentary aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick sandstone section of the Frio Formation, a regional brine and oil reservoir in the U.S. Gulf Coast. Fluid samples obtained from the injection and observation wells before CO2 injection showed a Na-Ca-Cl–type brine with 93,000 mg/L total dissolved solids (TDS) at near saturation with CH4 at reservoir conditions. Following CO2 breakthrough, samples showed sharp drops in pH (6.5–5.7), pronounced increases in alkalinity (100–3000 mg/L as HCO3) and Fe (30–1100 mg/L), and significant shifts in the isotopic compositions of H2O, dissolved inorganic carbon (DIC), and CH4. Geochemical modeling indicates that brine pH would have dropped lower but for the buffering by dissolution of carbonate and iron oxyhydroxides. This rapid dissolution of carbonate and other minerals could ultimately create pathways in the rock seals or well cements for CO2 and brine leakage. Dissolution of minerals, especially iron oxyhydroxides, could mobilize toxic trace metals and, where residual oil or suitable organics are present, the injected CO2 could also mobilize toxic organic compounds. Environmental impacts could be major if large brine volumes with mobilized toxic metals and organics migrated into potable groundwater. The δ18O values for brine and CO2 samples indicate that supercritical CO2 comprises ∼50% of pore-fluid volume ∼6 mo after the end of injection. Postinjection sampling, coupled with geochemical modeling, indicates that the brine gradually will return to its preinjection composition.

Determination of nitrite and nitrate in water samples by an automated hydrodynamic sequential injection method.

PubMed

Somnam, Sarawut; Jakmunee, Jaroon; Grudpan, Kate; Lenghor, Narong; Motomizu, Shoji

2008-12-01

An automated hydrodynamic sequential injection (HSI) system with spectrophotometric detection was developed. Thanks to the hydrodynamic injection principle, simple devices can be used for introducing reproducible microliter volumes of both sample and reagent into the flow channel to form stacked zones in a similar fashion to those in a sequential injection system. The zones were then pushed to the detector and a peak profile was recorded. The determination of nitrite and nitrate in water samples by employing the Griess reaction was chosen as a model. Calibration graphs with linearity in the range of 0.7 - 40 muM were obtained for both nitrite and nitrate. Detection limits were found to be 0.3 muM NO(2)(-) and 0.4 muM NO(3)(-), respectively, with a sample throughput of 20 h(-1) for consecutive determination of both the species. The developed system was successfully applied to the analysis of water samples, employing simple and cost-effective instrumentation and offering higher degrees of automation and low chemical consumption.

Measuring tissue back-pressure--in vivo injection forces during subcutaneous injection.

PubMed

Allmendinger, Andrea; Mueller, Robert; Schwarb, Edward; Chipperfield, Mark; Huwyler, Joerg; Mahler, Hanns-Christian; Fischer, Stefan

2015-07-01

Limited information is available on injection forces of parenterals representing the in vivo situation. Scope of the present study was to investigate the contribution of the subcutaneous (sc) tissue layer to injection forces during in vivo injection. Göttingen minipigs received injections of isotonic dextran solutions (1-100 mPas) into the plica inguinalis using different injection rates and volumes (0.025-0.2 mL/s and 2.5 vs. 4.5 mL). The contribution of the sc back-pressure to injection forces was found to increase linearly with viscosity and injection rate ranging from 0.6 ± 0.5 N to 1.0 ± 0.4 N (1 mPas), 0.7 ± 0.2 N to 2.4 ± 1.9 N (10 mPas), and 1.8 ± 0.6 N to 4.7 ± 3.3 N (20 mPas) for injection rates of 0.025 to 0.2 mL/s, respectively. Variability increased with viscosity and injection rate. Values are average values from 10 randomized injections. A maximum of 12.9 N was reached for 20 mPas at 0.2 mL/s; 6.9 ± 0.3 N was determined for 100 mPas at 0.025 mL/s. No difference was found between injection volumes of 2.5 and 4.5 mL. The contribution of the tissue was differentiated from the contribution of the injection device and a local temperature effect. This effect was leading to warming of the (equilibrated) sample in the needle, therefore smaller injection forces than expected compensating tissue resistance to some parts. When estimating injection forces representative for the in vivo situation, the contribution of the tissue has to be considered as well as local warming of the sample in the needle during injection.

Baxa MicroMacrocompounder for parenteral nutrition solutions in a pediatric hospital.

PubMed

Combeau, D; Rey, J B; Fontan, J E; Nouaille-Degorce, B; Brion, F

1999-01-01

The constant increase of parenteral nutrition (PN) manufacturing in our pediatric hospital led us to look for an automatic filling system. The aim of this study was to evaluate the MicroMacrocompounder (MM23) for compounding pediatric PN solutions. MM23 volumetric accuracy was tested with its different inlets (S, D, V) for volumes of sterile water for injection from 0.2 to 2900 mL. The influence of the solution viscosity and the source solution bottle replacements during the filling operation was also investigated. Manufacturing pediatric PN solutions was eventually assessed. Time to set up the system was 30 minutes. Maximum filling speeds with sterile water for injection were 860, 330, 154 mL/min for Vx, V and D inlets, respectively. Inlet S was not tested for MM23 filling speed. Minimal flush volume of 40 mL of sterile water for injection is necessary to clear the tube of residual ions. Average MM23 volumetric accuracy was < 5% for volumes > or = 0.5 mL for S and D inlets, and for volumes > or = 20 mL for V inlet. The volumetric accuracy was equal to 6.25% for 0.2 mL. In all experiments, volumetric accuracy was < 5%. The accuracy of electrolyte measurements performed on bag samples was less than 5% for 150 (74%) samples, between 5 and 10% for 27 (13%) samples and greater than 10% for 27 (13%) samples. Microbiological analysis showed no positive culture. The average manufacturing times were 56.8 +/- 4.5, 188.2 +/- 7.7 and 447.2 +/- 13.8 seconds for 130, 660 and 1800 mL bags, respectively. The MM23 compounder is suitable for compounding pediatric admixtures with source solutions volumes > or = 0.5 mL. This system has been used daily for five months in our department.

Trace analysis of glyphosate in water by capillary electrophoresis on a chip with high sample volume loadability.

PubMed

Horčičiak, Michal; Masár, Marián; Bodor, Róbert; Danč, Ladislav; Bel, Peter

2012-03-01

A new method for the determination of trace glyphosate (GLYP), non-selective pesticide, by CZE with online ITP pre-treatment of drinking waters on a column-coupling (CC) chip has been developed. CC chip was equipped with two injection channels of 0.9 and 9.9 μL volumes, two separation channels of 9.3 μL total volume and a pair of conductivity detectors. A very effective ITP sample clean-up performed in the first channel at low pH (3.2) was introduced for quick CZE resolution and detection of GLYP carried out at higher pH (6.1) in the second channel on the CC chip. The LOD for GLYP was estimated at 2.5 μg/L (15 nmol/L) using a 9.9 |mL volume of the injection channel. ITP-CZE analyses of model and real samples have provided very favorable intra-day (0.1-1.2% RSD) and inter-day (2.9% RSD) repeatabilities of the migration time for GLYP while 0.2-6.9% RSD values were typical for the peak area data. Recoveries of GLYP in spiked drinking water varied in the range of 99-109%. A minimum pre-treatment of drinking water (degassing and dilution) and a short analysis time (ca. 10 min) were distinctive features of ITP-CZE determinations of GLYP on the CC chip with high sample volume loaded, as well. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biomechanical comparative study of the stability of injectable pedicle screws with different lateral holes augmented with different volumes of polymethylmethacrylate in osteoporotic lumbar vertebrae.

PubMed

Liu, Da; Sheng, Jun; Luo, Yang; Huang, Chen; Wu, Hong-Hua; Zhou, Jiang-Jun; Zhang, Xiao-Jun; Zheng, Wei

2018-03-19

Polymethylmethacrylate (PMMA) is widely used for pedicle screw augmentation in osteoporosis. Until now, there had been no studies of the relationship between screw stability and the distribution and volume of PMMA. The objective of this study was to analyze the relationship between screw stability and the distribution pattern and injected volume of PMMA. This is a biomechanical comparison of injectable pedicle screws with different lateral holes augmented with different volumes of PMMA in cadaveric osteoporotic lumbar vertebrae. Forty-eight osteoporotic lumbar vertebrae were randomly divided into Groups A, B, and C with different pedicle screws (16 vertebrae in each group), and then each group was randomly divided into Subgroups 0, 1, 2, and 3 with different volumes of PMMA (four vertebra with eight pedicles in each subgroup). A pilot hole was prepared in advance using the same method in all samples. Type A and type B pedicle screws were directly inserted into vertebrae in Groups A and B, respectively, and then different volumes of PMMA (0, 1.0, 1.5, and 2.0 mL) were injected through the screws and into vertebrae in Subgroups 0, 1, 2, and 3. The pilot holes were filled with different volumes of PMMA (0, 1.0, 1.5, and 2.0 mL), and then the screws were inserted in Groups C0, C1, C2, and C3. Screw position and distribution of PMMA were evaluated radiographically, and axial pullout tests were performed to measure maximum axial pullout strength (F max ). Polymethylmethacrylate surrounded the anterior one-third of screws in the vertebral body in Groups A1, A2, and A3; the middle one-third of screws in the junction area of the vertebral body and the pedicle in Groups B1, B2, and B3; and the full length of screws evenly in both the vertebral body and the pedicle in Groups C1, C2, and C3. There was no malpositioning of screws or leakage of PMMA in any sample. Two-way analysis of variance revealed that two factors-distribution and volume of PMMA-significantly influenced F max (p<.05) but that they were not significantly correlated (p=.088). F max values in groups using augmentation with PMMA values significantly improved compared with those in groups without PMMA (p<.05). Polymethylmethacrylate can significantly enhance the stability of different injectable pedicle screws in osteoporotic lumbar vertebrae, and screw stability is significantly correlated with the distribution pattern and the injected volume of PMMA. The closer the PMMA to the pedicle and the greater the quantity of injected PMMA, the greater is the pedicle screw stability. Injection of 2.0 mL of PMMA through screws with four lateral 180° holes or of 1.0 mL of PMMA through screws with six lateral 180° holes increases the stability of pedicle screws. Copyright © 2018 Elsevier Inc. All rights reserved.

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid.

PubMed

van Staden, J F; Mashamba, Mulalo G; Stefan, Raluca I

2002-09-01

An on-line potentiometric sequential injection titration process analyser for the determination of acetic acid is proposed. A solution of 0.1 mol L(-1) sodium chloride is used as carrier. Titration is achieved by aspirating acetic acid samples between two strong base-zone volumes into a holding coil and by channelling the stack of well-defined zones with flow reversal through a reaction coil to a potentiometric sensor where the peak widths were measured. A linear relationship between peak width and logarithm of the acid concentration was obtained in the range 1-9 g/100 mL. Vinegar samples were analysed without any sample pre-treatment. The method has a relative standard deviation of 0.4% with a sample frequency of 28 samples per hour. The results revealed good agreement between the proposed sequential injection and an automated batch titration method.

Hydro-geophysical responses to the injection of CO2 in core plugs of Berea sandstone

NASA Astrophysics Data System (ADS)

Song, I.; Park, K. G.

2017-12-01

We have built a laboratory-scale core flooding system to measure the relative permeability of a core sample and the acoustic response to the CO2 saturation degree at in situ condition of pressure and temperature down to a few kilometer depths. The system consisted of an acoustic velocity core holder (AVC model from the Core Laboratories) between upstream where CO2 and H2O were injected separately and downstream where the mixed fluids came out of a core sample. Core samples with 4 cm in diameter and 5 cm in length of Berea sandstone were in turn placed in the core holder for confining and axial pressures. The flooding operations of the multiphase fluids were conducted through the sample at 40ºC in temperature and 8 MPa in backpressure. CO2 and H2O in the physical condition were injected separately into a sample at constant rate with various ratios. The two phases were mixed during flowing through the sample. The mixed fluids out of the sample were separated again by their different densities in a chamber equipped with a level gauge of the interface. From the level change of the water in the separator, we measured the volume of water coming out of the sample for each test with a constant ratio of the injection rates. Then it was possible to calculate the saturation degree of CO2 from the difference between input volume and output volume of water. The differential pressure between upstream and downstream was directly measured to calculate the relative permeability as a function of the CO2 saturation degree. We also conducted ultrasonic measurements using piezoelectric sensors on the end plugs. An electric pulse was given to a sensor on one end of sample, and then ultrasonic waves were recorded from the other end. The various ratios of injection rate of CO2 and H2O into Berea sandstone yielded a range of 0.1-0.7 in CO2 saturation degree. The relative permeability was obtained at the condition of steady-state flow for given stages from the velocity of each phase and the pressure gradient. The arrival time of P-wave became retarded and its amplitude became smaller as the degree of CO2 saturation increases. However no change was observed in S-wave in both characters. According to our results, time-lapse measurements of P-wave signals can be a monitoring tool of the subsurface migration of CO2, thus of detecting even its leakage.

Rapid and sensitive screening and selective quantification of antibiotics in human urine by two-dimensional ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

PubMed

Wang, He-Xing; Wang, Bin; Zhou, Ying; Jiang, Qing-Wu

2014-12-01

A rapid and sensitive method for the screening and selective quantification of antibiotics in urine by two-dimensional ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was developed. This method allowed the injection of 200 μL urine extract. The 200-μL injection volume used in this method increased the absolute sensitivity for target antibiotics in solvent by an average 13.3 times, with a range from 8.4 to 28.5 times, compared with the 10-μL conventional injection volume. A 96-well solid phase extraction procedure was established to eliminate the contamination on the chromatographic column resulting from the large-volume injection and increase the throughput of sample preparation. Fourteen target antibiotics from six common categories (β-lactams, quinolones, tetracyclines, macrolides, sulfonamides, and chloramphenicols) were selected as model compounds, and a database containing an additional 74 antibiotics was compiled for posttarget screening. The limit of detection of the target antibiotics, defined as a signal-to-noise ratio of 3, ranged from 0.04 to 1.99 ng/mL. The mean interday recoveries ranged between 79.6 and 121.3 %, with a relative standard deviation from 2.9 to 18.3 % at three spiking levels of 20 ng/mL, 50 ng/mL, and 100 ng/mL. This method was successfully applied in 60 real urine samples from schoolchildren aged 8-11 years, and four target antibiotics (azithromycin, sulfadiazine, trimethoprim, and oxytetracycline) and two posttarget antibiotics (sulfadimidine and cefaclor) were found in the urine samples. This method can be used as a large-scale biomonitoring tool for exposure of the human population to antibiotics.

Perilymph Kinetics of FITC-Dextran Reveals Homeostasis Dominated by the Cochlear Aqueduct and Cerebrospinal Fluid.

PubMed

Salt, A N; Gill, R M; Hartsock, J J

2015-06-01

Understanding how drugs are distributed in perilymph following local applications is important as local drug therapies are increasingly used to treat disorders of the inner ear. The potential contribution of cerebrospinal fluid (CSF) entry to perilymph homeostasis has been controversial for over half a century, largely due to artifactual contamination of collected perilymph samples with CSF. Measures of perilymph flow and of drug distribution following round window niche applications have both suggested a slow, apically directed flow occurs along scala tympani (ST) in the normal, sealed cochlea. In the present study, we have used fluorescein isothiocyanate-dextran as a marker to study perilymph kinetics in guinea pigs. Dextran is lost from perilymph more slowly than other substances so far quantified. Dextran solutions were injected from pipettes sealed into the lateral semicircular canal (SCC), the cochlear apex, or the basal turn of ST. After varying delays, sequential perilymph samples were taken from the cochlear apex or lateral SCC, allowing dextran distribution along the perilymphatic spaces to be quantified. Variability was low and findings were consistent with the injection procedure driving volume flow towards the cochlear aqueduct, and with volume flow during perilymph sampling driven by CSF entry at the aqueduct. The decline of dextran with time in the period between injection and sampling was consistent with both a slow volume influx of CSF (~30 nL/min) entering the basal turn of ST at the cochlear aqueduct and a CSF-perilymph exchange driven by pressure-driven fluid oscillation across the cochlear aqueduct. Sample data also allowed contributions of other processes, such as communications with adjacent compartments, to be quantified. The study demonstrates that drug kinetics in the basal turn of ST is complex and is influenced by a considerable number of interacting processes.

What controls the maximum magnitude of injection-induced earthquakes?

NASA Astrophysics Data System (ADS)

Eaton, D. W. S.

2017-12-01

Three different approaches for estimation of maximum magnitude are considered here, along with their implications for managing risk. The first approach is based on a deterministic limit for seismic moment proposed by McGarr (1976), which was originally designed for application to mining-induced seismicity. This approach has since been reformulated for earthquakes induced by fluid injection (McGarr, 2014). In essence, this method assumes that the upper limit for seismic moment release is constrained by the pressure-induced stress change. A deterministic limit is given by the product of shear modulus and the net injected fluid volume. This method is based on the assumptions that the medium is fully saturated and in a state of incipient failure. An alternative geometrical approach was proposed by Shapiro et al. (2011), who postulated that the rupture area for an induced earthquake falls entirely within the stimulated volume. This assumption reduces the maximum-magnitude problem to one of estimating the largest potential slip surface area within a given stimulated volume. Finally, van der Elst et al. (2016) proposed that the maximum observed magnitude, statistically speaking, is the expected maximum value for a finite sample drawn from an unbounded Gutenberg-Richter distribution. These three models imply different approaches for risk management. The deterministic method proposed by McGarr (2014) implies that a ceiling on the maximum magnitude can be imposed by limiting the net injected volume, whereas the approach developed by Shapiro et al. (2011) implies that the time-dependent maximum magnitude is governed by the spatial size of the microseismic event cloud. Finally, the sample-size hypothesis of Van der Elst et al. (2016) implies that the best available estimate of the maximum magnitude is based upon observed seismicity rate. The latter two approaches suggest that real-time monitoring is essential for effective management of risk. A reliable estimate of maximum plausible magnitude would clearly be beneficial for quantitative risk assessment of injection-induced seismicity.

Probing the water distribution in porous model sands with two immiscible fluids: A nuclear magnetic resonance micro-imaging study

NASA Astrophysics Data System (ADS)

Lee, Bum Han; Lee, Sung Keun

2017-10-01

The effect of the structural heterogeneity of porous networks on the water distribution in porous media, initially saturated with immiscible fluid followed by increasing durations of water injection, remains one of the important problems in hydrology. The relationship among convergence rates (i.e., the rate of fluid saturation with varying injection time) and the macroscopic properties and structural parameters of porous media have been anticipated. Here, we used nuclear magnetic resonance (NMR) micro-imaging to obtain images (down to ∼50 μm resolution) of the distribution of water injected for varying durations into porous networks that were initially saturated with silicone oil. We then established the relationships among the convergence rates, structural parameters, and transport properties of porous networks. The volume fraction of the water phase increases as the water injection duration increases. The 3D images of the water distributions for silica gel samples are similar to those of the glass bead samples. The changes in water saturation (and the accompanying removal of silicone oil) and the variations in the volume fraction, specific surface area, and cube-counting fractal dimension of the water phase fit well with the single-exponential recovery function { f (t) = a [ 1 -exp (- λt) ] } . The asymptotic values (a, i.e., saturated value) of the properties of the volume fraction, specific surface area, and cube-counting fractal dimension of the glass bead samples were greater than those for the silica gel samples primarily because of the intrinsic differences in the porous networks and local distribution of the pore size and connectivity. The convergence rates of all of the properties are inversely proportional to the entropy length and permeability. Despite limitations of the current study, such as insufficient resolution and uncertainty for the estimated parameters due to sparsely selected short injection times, the observed trends highlight the first analyses of the cube-counting fractal dimension (and other structural properties) and convergence rates in porous networks consisting of two fluid components. These results indicate that the convergence rates correlate with the geometric factor that characterizes the porous networks and transport property of the porous networks.

Induced earthquake magnitudes are as large as (statistically) expected

USGS Publications Warehouse

Van Der Elst, Nicholas; Page, Morgan T.; Weiser, Deborah A.; Goebel, Thomas; Hosseini, S. Mehran

2016-01-01

A major question for the hazard posed by injection-induced seismicity is how large induced earthquakes can be. Are their maximum magnitudes determined by injection parameters or by tectonics? Deterministic limits on induced earthquake magnitudes have been proposed based on the size of the reservoir or the volume of fluid injected. However, if induced earthquakes occur on tectonic faults oriented favorably with respect to the tectonic stress field, then they may be limited only by the regional tectonics and connectivity of the fault network. In this study, we show that the largest magnitudes observed at fluid injection sites are consistent with the sampling statistics of the Gutenberg-Richter distribution for tectonic earthquakes, assuming no upper magnitude bound. The data pass three specific tests: (1) the largest observed earthquake at each site scales with the log of the total number of induced earthquakes, (2) the order of occurrence of the largest event is random within the induced sequence, and (3) the injected volume controls the total number of earthquakes rather than the total seismic moment. All three tests point to an injection control on earthquake nucleation but a tectonic control on earthquake magnitude. Given that the largest observed earthquakes are exactly as large as expected from the sampling statistics, we should not conclude that these are the largest earthquakes possible. Instead, the results imply that induced earthquake magnitudes should be treated with the same maximum magnitude bound that is currently used to treat seismic hazard from tectonic earthquakes.

Hydrologic monitoring of a waste-injection well near Milton, Florida, June 1975 - December 1976

USGS Publications Warehouse

Pascale, Charles A.; Martin, J.B.

1977-01-01

Hydraulic and chemical data were collected through a monitoring program conducted by the U.S. Geological Survey at an industrial liquid-waste injection site 6 mi southwest of Milton, Fla., in Santa Rosa County. The injection system is described. Data include injection rates, volumes, and pressures; water-level data at three monitor wells and a standby injection well, and field and laboratory analyses of water samples from four wells. Hydraulic and geochemical effects of the waste-injection system at the plant as of December 31, 1976, have been detected only in the injection zone, the lower limestone of the Floridan aquifer. Increased pressures are evident at the three wells used to monitor the injection zone. Geochemical changes have been noted only at the deep-test monitor well closest to the injection well. (Woodard-USGS)

Foam injection molding of elastomers with iron microparticles

NASA Astrophysics Data System (ADS)

Volpe, Valentina; D'Auria, Marco; Sorrentino, Luigi; Davino, Daniele; Pantani, Roberto

2015-12-01

In this work, a preliminary study of foam injection molding of a thermoplastic elastomer, Engage 8445, and its microcomposite loaded with iron particles was carried out, in order to evaluate the effect of the iron microparticles on the foaming process. In particular, reinforced samples have been prepared by using nanoparticles at 2% by volume. Nitrogen has been used as physical blowing agent. Foamed specimens consisting of neat and filled elastomer were characterized by density measurements and morphological analysis. While neat Engage has shown a well developed cellular morphology far from the injection point, the addition of iron microparticles considerably increased the homogeneity of the cellular morphology. Engage/iron foamed samples exhibited a reduction in density greater than 32%, with a good and homogeneous cellular morphology, both in the transition and in the core zones, starting from small distances from the injection point.

OPTIMIZED DETERMINATION OF TRACE JET FUEL VOLATILE ORGANIC COMPOUNDS IN HUMAN BLOOD USING IN-FIELD LIQUID-LIQUID EXTRACTION WITH SUBSEQUENT LABORATORY GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS AND ON-COLUMN LARGE VOLUME INJECTION

EPA Science Inventory

A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing te...

Optimizations of packed sorbent and inlet temperature for large volume-direct aqueous injection-gas chromatography to determine high boiling volatile organic compounds in water.

PubMed

Yu, Bofan; Song, Yonghui; Han, Lu; Yu, Huibin; Liu, Yang; Liu, Hongliang

2014-08-22

For the expanded application area, fast trace analysis of certain high boiling point (i.e., 150-250 °C) volatile organic compounds (HVOCs) in water, a large volume-direct aqueous injection-gas chromatography (LV-DAI-GC) method was optimized for the following parameters: packed sorbent for sample on-line pretreatment, inlet temperature and detectors configuration. Using the composite packed sorbent self-prepared with lithium chloride and a type of diatomite, the method enabled safe injection of an approximately 50-100 μL sample at an inlet temperature of 150 °C in the splitless mode and separated HVOCs from water matrix in 2 min. Coupled with a flame ionization detector (FID), an electron capture detector (ECD) and a flame photometric detector (FPD), the method could simultaneously quantify 27 HVOCs that belong to seven subclasses (i.e., halogenated aliphatic hydrocarbons, chlorobenzenes, nitrobenzenes, anilines, phenols, polycyclic aromatic hydrocarbons and organic sulfides) in 26 min. Injecting a 50 μL sample without any enrichment step, such as cryotrap focusing, the limits of quantification (LOQs) for the 27 HVOCs was 0.01-3 μg/L. Replicate analyses of the 27 HVOCs spiked source and river water samples exhibited good precision (relative standard deviations ≤ 11.3%) and accuracy (relative errors ≤ 17.6%). The optimized LV-DAI-GC was robust and applicable for fast determination and automated continuous monitoring of HVOCs in surface water. Copyright © 2014 Elsevier B.V. All rights reserved.

On-line preconcentration and speciation of arsenic by flow injection hydride generation atomic absorption spectrophotometry.

PubMed

Narcise, Cristine Ingrid S; Coo, Lilibeth Dlc; Del Mundo, Florian R

2005-12-15

A flow injection-column preconcentration-hydride generation atomic absorption spectrophotometric (FI-column-HGAAS) method was developed for determining mug/l levels of As(III) and As(V) in water samples, with simultaneous preconcentration and speciation. The speciation scheme involved determining As(V) at neutral pH and As(III+V) at pH 12, with As(III) obtained by difference. The enrichment factor (EF) increased with increase in sample loading volume from 2.5 to 10ml, and for preconcentration using the chloride-form anion exchange column, EFs ranged from 5 to 48 for As(V) and 4 to 24 for As(III+V), with corresponding detection limits of 0.03-0.3 and 0.07-0.3mug/l. Linear concentration range (LCR) also varied with sample loading volume, and for a 5-ml sample was 0.3-5 and 0.2-8mug/l for As(V) and As(III+V), respectively. Sample throughput, which decreased with increase in sample volume, was 8-17 samples/h. For the hydroxide-form column, the EFS for 2.5-10ml samples were 3-23 for As(V) and 2-15 for As(III+V), with corresponding detection limits of 0.07-0.4 and 0.1-0.5mug/l. The LCR for a 5-ml sample was 0.3-10mug/l for As(V) and 0.2-20mug/l for As(III+V). Sample throughput was 10-20 samples/h. The developed method has been effectively applied to tap water and mineral water samples, with recoveries ranging from 90 to 102% for 5-ml samples passed through the two columns.

Reservoir Architecture Control on the Geometry of a CO2 Plume Using 4D Seismic, Sleipner Field.

NASA Astrophysics Data System (ADS)

Bitrus, Roy; Iacopini, David; Bond, Clare

2017-04-01

Time lapse seismic from the Sleipner field, Norwegian North Sea represents a unique database to understand the geometry of a saline aquifer, the Utsira Sand Formation, and its role in containing sequestered CO2. The heterogeneous high permeability Utsira Sand formation bounded by an overlying seal is surrounded by impermeable to semi-permeable intra-reservoir thin shale units that influence the migration of injected CO2. It is important to understand and verify the dynamics of injected CO2 plume migration as this ensures close to accurate predictions of the evolving and stable state of CO2 in storage projects. Previous detailed interpretation results of the thin shale units and permeability flow path chimneys within the Utsira Formation have been used in this research. The Utsira Cap rock, IUTS1 and IUTS1 (Intra-Utsira Shale Units) are the top three units that affect the containment and upward migration path of injected CO2. They are combined with seismic geobodies of the CO2 plume across time lapse data. Here, these seismic geobodies are created using 2 methods to delineate the 3D shape and the cubic volume occupancy of the CO2 plume within the reservoir. Method 1 employs the use of an envelope attribute volume, where samples are extracted from voxels that contain seismic trace amplitude values of injected CO2 across the 3D data. These extracted samples are then tracked throughout the target area and then classed and quantified as a CO2 geobodies. Method 2 applies the same concept; the only difference is the samples extracted from voxels are classed based on the proximity and connectivity of pre-defined amplitude values. Both methods employ the use of a Bayesian classifier which defines the probability density function used to categorise the extracted threshold values. Our result of the 3D geobody shapes are compared against the internal geometry of the reservoir which shows the influence of the cap rock and intra-reservoir thin shales on the CO2 plume acting as baffles and flow paths. The amount of injected CO2 is compared against the occupied volume of CO2 within the reservoir rock. Result values are plotted in graphs and they give an indication of the upper and lower end of reservoir volume occupied by injected supercritical CO2. These values are based on the porosity, permeability, density and temperature values of the rock volume, formation fluid and supercritical CO2. The results also show a decrease in effective rock volume occupied by CO2 reaching the Utsira top cap rock with increase in injected amounts of CO2. Our results indicate that the methods proposed can be applied to storage reservoirs in their early to mid-stages to help predict and understand the internal geometries of the reservoir unit and how they can affect the containment or upward migration flow of CO2. The CO2 volumetric measurement can also be used as a well-grounded assessment for future saline aquifer storage projects.

Polymeric microchip for the simultaneous determination of anions and cations by hydrodynamic injection using a dual-channel sequential injection microchip electrophoresis system.

PubMed

Gaudry, Adam J; Nai, Yi Heng; Guijt, Rosanne M; Breadmore, Michael C

2014-04-01

A dual-channel sequential injection microchip capillary electrophoresis system with pressure-driven injection is demonstrated for simultaneous separations of anions and cations from a single sample. The poly(methyl methacrylate) (PMMA) microchips feature integral in-plane contactless conductivity detection electrodes. A novel, hydrodynamic "split-injection" method utilizes background electrolyte (BGE) sheathing to gate the sample flows, while control over the injection volume is achieved by balancing hydrodynamic resistances using external hydrodynamic resistors. Injection is realized by a unique flow-through interface, allowing for automated, continuous sampling for sequential injection analysis by microchip electrophoresis. The developed system was very robust, with individual microchips used for up to 2000 analyses with lifetimes limited by irreversible blockages of the microchannels. The unique dual-channel geometry was demonstrated by the simultaneous separation of three cations and three anions in individual microchannels in under 40 s with limits of detection (LODs) ranging from 1.5 to 24 μM. From a series of 100 sequential injections the %RSDs were determined for every fifth run, resulting in %RSDs for migration times that ranged from 0.3 to 0.7 (n = 20) and 2.3 to 4.5 for peak area (n = 20). This system offers low LODs and a high degree of reproducibility and robustness while the hydrodynamic injection eliminates electrokinetic bias during injection, making it attractive for a wide range of rapid, sensitive, and quantitative online analytical applications.

Single-sample 99mTc-diethylenetriamine penta-acetate plasma clearance in advanced renal failure by the mean sojourn time approach.

PubMed

Gref, Margareta C; Karp, Kjell H

2009-03-01

The single-sample Tc-diethylenetriamine penta-acetate (DTPA) clearance method by Christensen and Groth is recommended by the Radionuclides in Nephrourology Committee on Renal Clearance for use in adults with an estimated glomerular filtration rate (GFR) > or = 30 ml/min. The purpose of this study was to test a new Tc-DTPA single-sample low clearance formula for GFR lesser than 30 ml/min. Twenty-one adult patients (29 investigations) were included. Reference clearance was calculated with both Cr-EDTA and Tc-DTPA according to Brøchner-Mortensen with samples drawn between 3 and 24 h. Single-sample clearance was calculated from a 24 h sample using the low clearance formula(Equation is included in full-text article.) C(t) is the activity of the tracer in the plasma sample t minutes after the injection and Q0 is the injected amount. ECV is the extracellular volume in ml defined as the distribution volume of the tracer. ECV is estimated from the body surface area as ECV=8116.6xbody surface area-28.2. The mean difference between reference and Tc-DTPA single-sample clearance was -0.5 ml/min (SD 1.0 ml/min) for Tc-DTPA and -0.8 ml/min (SD 1.2 ml/min) for Cr-EDTA as reference clearance. In adult patients it is possible, even with GFR lesser than 30 ml/min, to get an accurate determination of Tc-DTPA plasma clearance from a single sample using the mean sojourn time approach. The blood sample should be obtained about 24 h after injection of the GFR tracer.

Sample stacking of fast-moving anions in capillary zone electrophoresis with pH-suppressed electroosmotic flow.

PubMed

Quirino, J P; Terabe, S

1999-07-30

On-line sample concentration of fast moving inorganic anions by large volume sample stacking (LVSS) and field enhanced sample injection (FESI) with a water plug under acidic conditions is presented. Detection sensitivity enhancements were around 100 and 1000-fold for LVSS and FESI, respectively. However, reproducibility and linearity of response in the LVSS approach is superior compared to the FESI approach.

A system for accurate and automated injection of hyperpolarized substrate with minimal dead time and scalable volumes over a large range

NASA Astrophysics Data System (ADS)

Reynolds, Steven; Bucur, Adriana; Port, Michael; Alizadeh, Tooba; Kazan, Samira M.; Tozer, Gillian M.; Paley, Martyn N. J.

2014-02-01

Over recent years hyperpolarization by dissolution dynamic nuclear polarization has become an established technique for studying metabolism in vivo in animal models. Temporal signal plots obtained from the injected metabolite and daughter products, e.g. pyruvate and lactate, can be fitted to compartmental models to estimate kinetic rate constants. Modeling and physiological parameter estimation can be made more robust by consistent and reproducible injections through automation. An injection system previously developed by us was limited in the injectable volume to between 0.6 and 2.4 ml and injection was delayed due to a required syringe filling step. An improved MR-compatible injector system has been developed that measures the pH of injected substrate, uses flow control to reduce dead volume within the injection cannula and can be operated over a larger volume range. The delay time to injection has been minimized by removing the syringe filling step by use of a peristaltic pump. For 100 μl to 10.000 ml, the volume range typically used for mice to rabbits, the average delivered volume was 97.8% of the demand volume. The standard deviation of delivered volumes was 7 μl for 100 μl and 20 μl for 10.000 ml demand volumes (mean S.D. was 9 ul in this range). In three repeat injections through a fixed 0.96 mm O.D. tube the coefficient of variation for the area under the curve was 2%. For in vivo injections of hyperpolarized pyruvate in tumor-bearing rats, signal was first detected in the input femoral vein cannula at 3-4 s post-injection trigger signal and at 9-12 s in tumor tissue. The pH of the injected pyruvate was 7.1 ± 0.3 (mean ± S.D., n = 10). For small injection volumes, e.g. less than 100 μl, the internal diameter of the tubing contained within the peristaltic pump could be reduced to improve accuracy. Larger injection volumes are limited only by the size of the receiving vessel connected to the pump.

Studies in fat grafting: Part I. Effects of injection technique on in vitro fat viability and in vivo volume retention.

PubMed

Chung, Michael T; Paik, Kevin J; Atashroo, David A; Hyun, Jeong S; McArdle, Adrian; Senarath-Yapa, Kshemendra; Zielins, Elizabeth R; Tevlin, Ruth; Duldulao, Chris; Hu, Michael S; Walmsley, Graham G; Parisi-Amon, Andreina; Momeni, Arash; Rimsa, Joe R; Commons, George W; Gurtner, Geoffrey C; Wan, Derrick C; Longaker, Michael T

2014-07-01

Fat grafting has become increasingly popular for the correction of soft-tissue deficits at many sites throughout the body. Long-term outcomes, however, depend on delivery of fat in the least traumatic fashion to optimize viability of the transplanted tissue. In this study, the authors compare the biological properties of fat following injection using two methods. Lipoaspiration samples were obtained from five female donors, and cellular viability, proliferation, and lipolysis were evaluated following injection using either a modified Coleman technique or an automated, low-shear device. Comparisons were made to minimally processed, uninjected fat. Volume retention was also measured over 12 weeks after injection of fat under the scalp of immunodeficient mice using either the modified Coleman technique or the Adipose Tissue Injector. Finally, fat grafts were analyzed histologically. Fat viability and cellular proliferation were both significantly greater with the Adipose Tissue Injector relative to injection with the modified Coleman technique. In contrast, significantly less lipolysis was noted using the automated device. In vivo fat volume retention was significantly greater than with the modified Coleman technique at the 4-, 6-, 8-, and 12-week time points. This corresponded to significantly greater histologic scores for healthy fat and lower scores for injury following injection with the device. Biological properties of injected tissues reflect how disruptive and harmful techniques for placement of fat may be, and the authors' in vitro and in vivo data both support the use of the automated, low-shear devices compared with the modified Coleman technique.

Studies in Fat Grafting: Part I. Effects of Injection Technique on in vitro Fat Viability and in vivo Volume Retention

PubMed Central

Chung, Michael T.; Paik, Kevin J.; Atashroo, David A.; Hyun, Jeong S.; McArdle, Adrian; Senarath-Yapa, Kshemendra; Zielins, Elizabeth R.; Tevlin, Ruth; Duldulao, Chris; Hu, Michael S.; Walmsley, Graham G.; Parisi-Amon, Andreina; Momeni, Arash; Rimsa, Joe R.; Commons, George W.; Gurtner, Geoffrey C.; Wan, Derrick C.; Longaker, Michael T.

2014-01-01

Background Fat grafting has become increasingly popular for the correction of soft tissue deficits at many sites throughout the body. Long-term outcomes, however, depend on delivery of fat in the least traumatic fashion to optimize viability of the transplanted tissue. In this study, we compare the biologic properties of fat following injection using two methods. Methods Lipoaspiration samples were obtained from five female donors and cellular viability, proliferation, and lipolysis were evaluated following injection using either a modified Coleman technique or an automated, low shear device. Comparisons were made to minimally processed, uninjected fat. Volume retention was also measured over twelve weeks following injection of fat under the scalp of immunodeficient mice using either the modified Coleman technique or the Adipose Tissue Injector. Finally, fat grafts were analyzed histologically. Results Fat viability and cellular proliferation were both significantly greater with the Adipose Tissue Injector relative to injection with the modified Coleman technique. In contrast, significantly less lipolysis was noted using the automated device. In vivo fat volume retention was significantly greater than with the modified Coleman technique at 4, 6, 8, and 12 week time points. This corresponded with significantly greater histological scores for healthy fat and lower scores for injury following injection with the device. Conclusions Biological properties of injected tissues reflect how disruptive and harmful techniques for placement of fat may be, and our in vitro and in vivo data both support the use of the automated, low shear devices compared to the modified Coleman technique. PMID:24622574

Objective Analysis of Poly-L-Lactic Acid Injection Efficacy in Different Settings.

PubMed

Byun, Sang-Young; Seo, Koo-Il; Shin, Jung-Won; Kwon, Soon-Hyo; Park, Mi-Sook; Lee, Joshua; Park, Kyoung-Chan; Na, Jung-Im; Huh, Chang-Hun

2015-12-01

Poly-L-lactic acid (PLLA) filler is known to have continuous volume effect. The objective of this study is to analyze objective volume effect of PLLA in different settings of injection schedule on the cheek. A split-face, evaluator-blind randomized study in 24 volunteers was conducted. One side was injected 3 times with 4 cc dose and the other side was injected 2 times with 6 cc dose per visit. Facial volume loss scale (FVLS) and Vectra were evaluated. Measured average FVLS showed statistically significant improvement both in 3 and 2 times injection sides and maintained efficacy until 12 months. Vectra showed volume difference (cc) between before and after injection. In 3 times injection side, it was increased 2.12 (after 1 month) to 3.17 (after 12 months). In 2 times injection side, it was increased 2.26 (after 1 month) to 3.19 (after 12 months). Gradual volume improvement over 12 months was statistically significant in both sides. There was no statistically significant difference between 3 and 2 times injection in FVLS and Vectra. There was no severe adverse event. Poly-L-lactic acid has continuous volume effect and there was no significant difference by injection times at the same total injection volume.

Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

PubMed

Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

2018-02-01

A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

Pharmacokinetic-pharmacodynamic study of subcutaneous injection of depot nandrolone decanoate using dried blood spots sampling coupled with ultrapressure liquid chromatography tandem mass spectrometry assays.

PubMed

Singh, Gurmeet K S; Turner, Leo; Desai, Reena; Jimenez, Mark; Handelsman, David J

2014-07-01

Testosterone (T) and nandrolone (N) esters require deep im injections by medical personnel but these often deposit injectate into sc fat so that more convenient sc self-administration may be feasible. To investigate the feasibility and pharmacology of sc injection of N decanoate in healthy men using dried blood spot (DBS) for frequent blood sampling without clinic visits. Healthy male volunteers received 100 mg N decanoate by a single sc injection. Finger-prick capillary blood was spotted onto filter paper before injection daily at home for 21 d and stored at room temperature. Venous whole blood was also spotted onto filter paper before and weekly for 3 wk after injection. DBS were extracted for assay of N and T by liquid chromatography tandem mass spectrometry in a single batch with serum concentrations estimated with adjustment for capillary blood sample volume and hematocrit to define peak (N) or nadir (T) time and concentration from individual daily measurements. Daily serum N peaked 2.50 ± 0.25 (SEM) ng/mL at a median (range) of 6 (4-13) days causing a reduction in serum T from 3.50 ± 0.57 ng/mL at baseline to a nadir of 0.38 ± 0.13 (SEM) ng/mL (89 ± 3% suppression) at a median (range) of 8 (5-16) days. Simultaneously sampled capillary, venous whole blood, and serum gave almost identical results for serum T and N. Finger-pricks and sc injections were well tolerated. This study demonstrates that A) DBS sampling with liquid chromatography mass spectrometry steroid analysis achieves frequent time sampling in the community without requiring clinic visits, venesection, or frozen serum storage, and B) androgen esters in an oil vehicle can be delivered effectively by sc injection, thus avoiding the need for medically supervised deep-im injections.

Target location after deep cerebral biopsies using low-volume air injection in 75 patients. Results and technical note.

PubMed

Poca, Maria A; Martínez-Ricarte, Francisco-Ramon; Gándara, Dario F; Coscojuela, Pilar; Martínez-Sáez, Elena; Sahuquillo, Juan

2017-10-01

Stereotactic biopsy is a minimally invasive technique that allows brain tissue samples to be obtained with low risk. Classically, different techniques have been used to identify the biopsy site after surgery. To describe a technique to identify the precise location of the target in the postoperative CT scan using the injection of a low volume of air into the biopsy cannula. Seventy-five biopsies were performed in 65 adults and 10 children (40 males and 35 females, median age 51 years). Frame-based biopsy was performed in 46 patients, while frameless biopsy was performed in the remaining 29 patients. In both systems, after brain specimens had been collected and with the biopsy needle tip in the center of the target, a small volume of air (median 0.7 cm 3 ) was injected into the site. A follow-up CT scan was performed in all patients. Intracranial air in the selected target was present in 69 patients (92%). No air was observed in two patients (air volume administered in these 2 cases was below 0.7 cm 3 ), while in the remaining four patients blood content was observed in the target. The diagnostic yield in this series was 97.3%. No complications were found to be associated with intracranial air injection in any of the 75 patients who underwent this procedure. The air-injection maneuver proposed for use in stereotactic biopsies of intracranial mass lesions is a safe and reliable technique that allows the exact biopsy site to be located without any related complications.

Mechanical Weakening during Fluid Injection in Critically Stressed Sandstones with Acoustic Monitoring

NASA Astrophysics Data System (ADS)

David, C.; Dautriat, J. D.; Sarout, J.; Macault, R.; Bertauld, D.

2014-12-01

Water weakening is a well-known phenomenon which can lead to subsidence during the production of hydrocarbon reservoirs. The example of the Ekofisk oil field in the North Sea has been well documented for years. In order to assess water weakening effects in reservoir rocks, previous studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks saturated either with water or with inert fluids. However, little attention has been paid so far on the mechanical behaviour during the fluid injection stage, like in enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behaviour of Sherwood sandstone, a weakly-consolidated sandstone sampled at Ladram Bay in UK. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties and to derive the acoustic signature of the saturation front for each fluid. The specimens were instrumented with 16 ultrasonic P-wave transducers for both passive and active acoustic monitoring during fluid injection and loading. After conducting standard triaxial tests on three samples saturated with air, water and oil respectively, mechanical creep tests were conducted on dry samples loaded at 80% of the compressive strength of the dry rock. While these conditions are kept constant, a fluid is injected at the bottom end of the sample with a low back pressure (0.5 MPa) to minimize effective stress variations during injection. Both water and oil were used as the injected pore fluid in two experiments. As soon as the fluids start to flow into the samples, creep is taking place with a much higher strain rate for water injection compared to oil injection. A transition from secondary creep to tertiary creep is observed in the water injection test whereas in the oil injection test no significant creep acceleration is observed after one pore volume of oil was injected. The most remarkable difference is that water injection induces mechanical instability and failure, whereas oil injection does not. This was confirmed by the analysis of acoustic emissions activity and post-mortem sample imaging using CT scan. Contrasting evolutions of the P wave velocity during the fluid front propagation were also observed in both experiments.

Stackable differential mobility analyzer for aerosol measurement

DOEpatents

Cheng, Meng-Dawn [Oak Ridge, TN; Chen, Da-Ren [Creve Coeur, MO

2007-05-08

A multi-stage differential mobility analyzer (MDMA) for aerosol measurements includes a first electrode or grid including at least one inlet or injection slit for receiving an aerosol including charged particles for analysis. A second electrode or grid is spaced apart from the first electrode. The second electrode has at least one sampling outlet disposed at a plurality different distances along its length. A volume between the first and the second electrode or grid between the inlet or injection slit and a distal one of the plurality of sampling outlets forms a classifying region, the first and second electrodes for charging to suitable potentials to create an electric field within the classifying region. At least one inlet or injection slit in the second electrode receives a sheath gas flow into an upstream end of the classifying region, wherein each sampling outlet functions as an independent DMA stage and classifies different size ranges of charged particles based on electric mobility simultaneously.

Amplification volume reduction on DNA database samples using FTA™ Classic Cards.

PubMed

Wong, Hang Yee; Lim, Eng Seng Simon; Tan-Siew, Wai Fun

2012-03-01

The DNA forensic community always strives towards improvements in aspects such as sensitivity, robustness, and efficacy balanced with cost efficiency. Therefore our laboratory decided to study the feasibility of PCR amplification volume reduction using DNA entrapped in FTA™ Classic Card and to bring cost savings to the laboratory. There were a few concerns the laboratory needed to address. First, the kinetics of the amplification reaction could be significantly altered. Second, an increase in sensitivity might affect interpretation due to increased stochastic effects even though they were pristine samples. Third, statics might cause FTA punches to jump out of its allocated well into another thus causing sample-to-sample contamination. Fourth, the size of the punches might be too small for visual inspection. Last, there would be a limit to the extent of volume reduction due to evaporation and the possible need of re-injection of samples for capillary electrophoresis. The laboratory had successfully optimized a reduced amplification volume of 10 μL for FTA samples. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Rapid method for measuring rotenone in water at piscicidal concentrations

USGS Publications Warehouse

Dawson, V.K.; Harman, P.D.; Schultz, D.P.; Allen, J.L.

1983-01-01

A high-performance liquid chromatography (HPLC) procedure that is rapid, specific, and sensitive (limit of detection <0.005 mg/liter) was developed for monitoring application and degradation rates of rotenone. For analysis, a water sample is buffered to pH 5 and injected through a Sep Pak(R) C18 disposable cartridge. The cartridge adsorbs and retains the rotenone which then can be eluted quantitatively from the cartridge with a small volume of methanol. This step effectively concentrates the sample and provides sample cleanup. The methanol extract is analyzed directly by HPLC on an MCH 10 reverse-phase column; methanol: water (75:25, volume : volume) is the mobile phase and flow rate is 1.5 ml/minute. The rotenone is detected by ultraviolet spectrophotometry at a wavelength of 295 nm.

DETERMINATION OF PESTICIDES IN COMPOSITE DIETARY SAMPLES BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY IN THE SELECTED ION MONITORING MODE USING A TEMPERATURE PROGRAMMABLE LARGE VOLUME INJECTOR WITH PRE-SEPARATION COLUMN

EPA Science Inventory

Use of a temperature-programmable pre-separation column in the gas chromatographic injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reduci...

Methods for the preparation and analysis of solids and suspended solids for total mercury

USGS Publications Warehouse

Olund, Shane D.; DeWild, John F.; Olson, Mark L.; Tate, Michael T.

2004-01-01

The methods documented in this report are utilized by the Wisconsin District Mercury Lab for analysis of total mercury in solids (soils and sediments) and suspended solids (isolated on filters). Separate procedures are required for the different sample types. For solids, samples are prepared by room-temperature acid digestion and oxidation with aqua regia. The samples are brought up to volume with a 5 percent bromine monochloride solution to ensure complete oxidation and heated at 50?C in an oven overnight. Samples are then analyzed with an automated flow injection system incorporating a cold vapor atomic fluorescence spectrometer. A method detection limit of 0.3 ng of mercury per digestion bomb was established using multiple analyses of an environmental sample. Based on the range of masses processed, the minimum sample reporting limit varies from 0.6 ng/g to 6 ng/g. Suspended solids samples are oxidized with a 5 percent bromine monochloride solution and held at 50?C in an oven for 5 days. The samples are then analyzed with an automated flow injection system incorporating a cold vapor atomic fluorescence spectrometer. Using a certified reference material as a surrogate for an environmental sample, a method detection limit of 0.059 ng of mercury per filter was established. The minimum sample reporting limit varies from 0.059 ng/L to 1.18 ng/L, depending on the volume of water filtered.

Updates to Simulation of a Single-Element Lean-Direct Injection Combustor Using Arbitary Polyhedral Meshes

NASA Technical Reports Server (NTRS)

Wey, Thomas; Liu, Nan-Suey

2015-01-01

This paper summarizes the procedures of (1) generating control volumes anchored at the nodes of a mesh; and (2) generating staggered control volumes via mesh reconstructions, in terms of either mesh realignment or mesh refinement, as well as presents sample results from their applications to the numerical solution of a single-element LDI combustor using a releasable edition of the National Combustion Code (NCC).

Water-level altitudes and continuous and discrete water quality at and near an aquifer storage and recovery site, Bexar, Atascosa, and Wilson Counties, Texas, June 2004-September 2011

USGS Publications Warehouse

Crow, Cassi L.

2012-01-01

The U.S. Geological Survey (USGS), in cooperation with the San Antonio Water System (SAWS), collected data during 2004–11 to characterize the quality of native groundwater from the San Antonio segment of the Edwards aquifer (hereinafter, Edwards aquifer) and preinjection and postinjection water from the Carrizo aquifer (informal name commonly applied to the upper part of the Carrizo-Wilcox aquifer in the area) at and near an aquifer storage and recovery (ASR) site in Bexar, Atascosa, and Wilson Counties, Texas. Daily mean water-level altitude, water temperature, and specific conductance were measured continuously in a monitoring well on the ASR site to determine how injection and withdrawal at the ASR site might affect local groundwater. Groundwater samples were collected and analyzed for selected physical properties and constituents to characterize the quality of native groundwater from the Edwards aquifer and preinjection and postinjection water from the Carrizo aquifer near the ASR site to provide a better understanding of possible changes in the quality of groundwater near an active ASR site that might result from the mixing of water from different aquifers. During injection periods, the water-level altitude in the monitoring well generally increased as the amount of water being injected into all wells at the ASR site increased and decreased as the amount of water being injected into all wells at the ASR site decreased. During withdrawal periods, the water-level altitude in the monitoring well generally increased as the total volume of water being withdrawn from all wells at the ASR site decreased and generally decreased as the total volume of water being withdrawn from all wells increased. Daily mean water temperature fluctuated by less than 1 degree Celsius and was determined to be independent of injection or withdrawal conditions at the ASR site. Changes in daily mean specific-conductance values measured at four depths in the monitoring well at the ASR site occurred without regard to total ASR site injection or withdrawal volumes. No substantial differences were measured over time in major-ion, trace-element, or isotope chemistry of water samples collected from the wells that supplied water from the Edwards aquifer. Little variation in water chemistry was detected in the samples collected from four wells designed to inject and withdraw water at the ASR site, regardless of whether the ASR site was injecting or withdrawing water. The similarity of major-ion and isotope chemistry between the Edwards aquifer source wells and the four ASR wells indicates that little, if any, migration of injected water away from the ASR wells has occurred. In a well located closest to the ASR site in the direction of regional flow for the Carrizo aquifer, a greater alkalinity value and a smaller concentration of chloride were measured in the most recent sample than in all other samples collected at this well. Substantial increases in dissolved iron and manganese concentrations also were observed in this well. The increased alkalinity value and dissolved iron and manganese concentrations and the decreased chloride concentration in the well could indicate that the injected water from the Edwards aquifer had begun to move into at least a part of the strata supplying these wells and might be causing iron and manganese mobilization in the Carrizo aquifer.

Development of an automated flow injection analysis system for determination of phosphate in nutrient solutions.

PubMed

Karadağ, Sevinç; Görüşük, Emine M; Çetinkaya, Ebru; Deveci, Seda; Dönmez, Koray B; Uncuoğlu, Emre; Doğu, Mustafa

2018-01-25

A fully automated flow injection analysis (FIA) system was developed for determination of phosphate ion in nutrient solutions. This newly developed FIA system is a portable, rapid and sensitive measuring instrument that allows on-line analysis and monitoring of phosphate ion concentration in nutrient solutions. The molybdenum blue method, which is widely used in FIA phosphate analysis, was adapted to the developed FIA system. The method is based on the formation of ammonium Mo(VI) ion by reaction of ammonium molybdate with the phosphate ion present in the medium. The Mo(VI) ion then reacts with ascorbic acid and is reduced to the spectrometrically measurable Mo(V) ion. New software specific for flow analysis was developed in the LabVIEW development environment to control all the components of the FIA system. The important factors affecting the analytical signal were identified as reagent flow rate, injection volume and post-injection flow path length, and they were optimized using Box-Behnken experimental design and response surface methodology. The optimum point for the maximum analytical signal was calculated as 0.50 mL min -1 reagent flow rate, 100 µL sample injection volume and 60 cm post-injection flow path length. The proposed FIA system had a sampling frequency of 100 samples per hour over a linear working range of 3-100 mg L -1 (R 2  = 0.9995). The relative standard deviation (RSD) was 1.09% and the limit of detection (LOD) was 0.34 mg L -1 . Various nutrient solutions from a tomato-growing hydroponic greenhouse were analyzed with the developed FIA system and the results were found to be in good agreement with vanadomolybdate chemical method findings. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Enhancing concentration and mass sensitivities for liquid chromatography trace analysis of clopyralid in drinking water.

PubMed

Gu, Binghe; Meldrum, Brian; McCabe, Terry; Phillips, Scott

2012-01-01

A theoretical treatment was developed and validated that relates analyte concentration and mass sensitivities to injection volume, retention factor, particle diameter, column length, column inner diameter and detection wavelength in liquid chromatography, and sample volume and extracted volume in solid-phase extraction (SPE). The principles were applied to improve sensitivity for trace analysis of clopyralid in drinking water. It was demonstrated that a concentration limit of detection of 0.02 ppb (μg/L) for clopyralid could be achieved with the use of simple UV detection and 100 mL of a spiked drinking water sample. This enabled reliable quantitation of clopyralid at the targeted 0.1 ppb level. Using a buffered solution as the elution solvent (potassium acetate buffer, pH 4.5, containing 10% of methanol) in the SPE procedures was found superior to using 100% methanol, as it provided better extraction recovery (70-90%) and precision (5% for a concentration at 0.1 ppb level). In addition, the eluted sample was in a weaker solvent than the mobile phase, permitting the direct injection of the extracted sample, which enabled a faster cycle time of the overall analysis. Excluding the preparation of calibration standards, the analysis of a single sample, including acidification, extraction, elution and LC run, could be completed in 1 h. The method was used successfully for the determination of clopyralid in over 200 clopyralid monoethanolamine-fortified drinking water samples, which were treated with various water treatment resins. Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Environmental assessment of NH3 injection for an industrial package boiler. Volume 2. Data supplement. Final report, January 1983-January 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castaldini, C.; DeRosier, R.; Waterland, L.R.

1986-02-01

The report discusses emission results from comprehensive flue-gas sampling of a gas- and oil-fired industrial boiler equipped with Exxon's Thermal DeNOx Ammonia Injection Process for NOx reduction. Comprehensive emission measurements included continuous monitoring of flue gas emissions; source assessment sampling system (SASS) tests; EPA Method 5/17 for solid and condensible particulate emissions and ammonia emissions; controlled condensation system for SO2 and SO3; and N2O emission sampling. Ammonia injection at a NH3/NO molar ratio of 2.52 gave a NOx reduction of 41% from an uncontrolled level of 234 ppm to a controlled level of 137 ppm. NH3 emissions increased from 11more » ppm for the baseline to an average of 430 ppm for ammonia injection. Nitrous oxide, N2O, was reduced 68% from a 50 ppm baseline level to a 17 ppm controlled level. Total particulate emissions increased by an order of magnitude from a baseline of 17.7 ng/J to a controlled level of 182 ng/J.« less

A rapid and accurate method for determining protein content in dairy products based on asynchronous-injection alternating merging zone flow-injection spectrophotometry.

PubMed

Liang, Qin-Qin; Li, Yong-Sheng

2013-12-01

An accurate and rapid method and a system to determine protein content using asynchronous-injection alternating merging zone flow-injection spectrophotometry based on reaction between coomassie brilliant blue G250 (CBBG) and protein was established. Main merit of our approach is that it can avoid interferences of other nitric-compounds in samples, such as melamine and urea. Optimized conditions are as follows: Concentrations of CBBG, polyvinyl alcohol (PVA), NaCl and HCl are 150 mg/l, 30 mg/l, 0.1 mol/l and 1.0% (v/v), respectively; volumes of the sample and reagent are 150 μl and 30 μl, respectively; length of a reaction coil is 200 cm; total flow rate is 2.65 ml/min. The linear range of the method is 0.5-15 mg/l (BSA), its detection limit is 0.05 mg/l, relative standard deviation is less than 1.87% (n=11), and analytical speed is 60 samples per hour. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rapid and direct determination of glyphosate, glufosinate, and aminophosphonic acid by online preconcentration CE with contactless conductivity detection.

PubMed

See, Hong Heng; Hauser, Peter C; Ibrahim, Wan Aini Wan; Sanagi, Mohd Marsin

2010-01-01

Rapid and direct online preconcentration followed by CE with capacitively coupled contactless conductivity detection (CE-C(4)D) is evaluated as a new approach for the determination of glyphosate, glufosinate (GLUF), and aminophosphonic acid (AMPA) in drinking water. Two online preconcentration techniques, namely large volume sample stacking without polarity switching and field-enhanced sample injection, coupled with CE-C(4)D were successfully developed and optimized. Under optimized conditions, LODs in the range of 0.01-0.1 microM (1.7-11.1 microg/L) and sensitivity enhancements of 48- to 53-fold were achieved with the large volume sample stacking-CE-C(4)D method. By performing the field-enhanced sample injection-CE-C(4)D procedure, excellent LODs down to 0.0005-0.02 microM (0.1-2.2 microg/L) as well as sensitivity enhancements of up to 245- to 1002-fold were obtained. Both techniques showed satisfactory reproducibility with RSDs of peak height of better than 10%. The newly established approaches were successfully applied to the analysis of glyphosate, glufosinate, and aminophosphonic acid in spiked tap drinking water.

Hydrologic data for a subsurface waste-injection site at Mulberry, Florida; 1972-77

USGS Publications Warehouse

Wilson, William Edward; Parsons, David C.; Spechler, R.M.

1979-01-01

Since October 1972, industrial liquid waste has been injected into a brine aquifer of limestone and dolomite in Mulberry, FL., at a depth of more than 4,000 feet below land surface. During 1977, the injection rate was about 8.8 million gallons per month. To determine what effect the injected waste has on the ground-water body, water levels have been measured and water samples collected from two monitor wells that tap different permeable zones above the injection zone, and from a satellite monitor well that taps the injection zone. The monitor wells are in the annulus of the injection well, and the satellite monitor well is 2,291 feet from the injection well. This report updates previous data reports and includes all hydrologic data collected by the U.S. Geological Survey during 1972-77. Included is a table of well-construction data, a graph showing the volume of waste injected each month, and hydrographs of the annulus monitor wells and the satellite monitor well. (Woodard-USGS)

New Cost-Effective Method for Long-Term Groundwater Monitoring Programs

DTIC Science & Technology

2013-05-01

with a small-volume, gas -tight syringe (< 1 mL) and injected directly into the field-portable GC. Alternatively, the well headspace sample can be...according to manufacturers’ protocols. Isobutylene was used as the calibration standard for the PID. The standard gas mixtures were used for 3-point...monitoring wells are being evaluated: 1) direct headspace sampling, 2) sampling tube with gas permeable membrane, and 3) gas -filled passive vapor

A method for the direct injection and analysis of small volume human blood spots and plasma extracts containing high concentrations of organic solvents using revered-phase 2D UPLC/MS.

PubMed

Rainville, Paul D; Simeone, Jennifer L; Root, Dan S; Mallet, Claude R; Wilson, Ian D; Plumb, Robert S

2015-03-21

The emergence of micro sampling techniques holds great potential to improve pharmacokinetic data quality, reduce animal usage, and save costs in safety assessment studies. The analysis of these samples presents new challenges for bioanalytical scientists, both in terms of sample processing and analytical sensitivity. The use of two dimensional LC/MS with, at-column-dilution for the direct analysis of highly organic extracts prepared from biological fluids such as dried blood spots and plasma is demonstrated. This technique negated the need to dry down and reconstitute, or dilute samples with water/aqueous buffer solutions, prior to injection onto a reversed-phase LC system. A mixture of model drugs, including bromhexine, triprolidine, enrofloxacin, and procaine were used to test the feasibility of the method. Finally an LC/MS assay for the probe pharmaceutical rosuvastatin was developed from dried blood spots and protein-precipitated plasma. The assays showed acceptable recovery, accuracy and precision according to US FDA guidelines. The resulting analytical method showed an increase in assay sensitivity of up to forty fold as compared to conventional methods by maximizing the amount loaded onto the system and the MS response for the probe pharmaceutical rosuvastatin from small volume samples.

A study for the installation of the TEXT heavy-ion beam probe on DIII-D

NASA Astrophysics Data System (ADS)

Edmonds, P. H.; Solano, E. R.; Bravenec, R. V.; Wootton, A. J.; Schoch, P. M.; Crowley, T. P.; Hickok, R. L.; West, W. P.; Leuer, J.; Anderson, P.

1997-01-01

An assessment of the feasibility of installing the TEXT 2 MeV heavy-ion beam probe on the DIII-D tokamak has been completed. Detailed drawings of the machine cross section were imported into the CAD application AutoCAD. A set of programs written in AutoLisp were used to generate trajectories. Displays of the accessible cross section of the plasma, scan lines for the entire range of primary beam energy and injection angle ranges, and sample-volume dimensions can be rapidly generated. Because of the large deflection between the primary input beam and the emergent secondary beam, either the analyzer needs to be tracked over a ±20° angle or secondary poloidal deflector plates need to be installed at the exit port. Toroidal deflector plates will be installed at both the injection and exit ports to compensate for toroidal displacements and deflections. The sample volumes generated by this procedure are within a few centimeters of the locations derived from a full three-dimensional calculation.

Transport of fluorobenzoate tracers in a vegetated hydrologic control volume: 1. Experimental results

NASA Astrophysics Data System (ADS)

Queloz, Pierre; Bertuzzo, Enrico; Carraro, Luca; Botter, Gianluca; Miglietta, Franco; Rao, P. S. C.; Rinaldo, Andrea

2015-04-01

This paper reports about the experimental evidence collected on the transport of five fluorobenzoate tracers injected under controlled conditions in a vegetated hydrologic volume, a large lysimeter (fitted with load cells, sampling ports, and an underground chamber) where two willows prompting large evapotranspiration fluxes had been grown. The relevance of the study lies in the direct and indirect measures of the ways in which hydrologic fluxes, in this case, evapotranspiration from the upper surface and discharge from the bottom drainage, sample water and solutes in storage at different times under variable hydrologic forcings. Methods involve the accurate control of hydrologic inputs and outputs and a large number of suitable chemical analyses of water samples in discharge waters. Mass extraction from biomass has also been performed ex post. The results of the 2 year long experiment established that our initial premises on the tracers' behavior, known to be sorption-free under saturated conditions which we verified in column leaching tests, were unsuitable as large differences in mass recovery appeared. Issues on reactivity thus arose and were addressed in the paper, in this case attributed to microbial degradation and solute plant uptake. Our results suggest previously unknown features of fluorobenzoate compounds as hydrologic tracers, potentially interesting for catchment studies owing to their suitability for distinguishable multiple injections, and an outlook on direct experimental closures of mass balance in hydrologic transport volumes involving fluxes that are likely to sample differently stored water and solutes.

Application of a novel large-volume injection method using a stomach-shaped inlet liner in capillary gas chromatographic trace analysis of dioxins in human milk and plasma.

PubMed

Saito, Koichi; Ohmura, Atsuko; Takekuma, Mikiko; Sasano, Ryoichi; Matsuki, Yasuhiko; Nakazawa, Hiroyuki

2007-06-01

A newly developed large-volume injection (LVI) technique that employs a unique stomach-shaped inlet liner (SSIL) inside of a programmable temperature vaporizer was used for the determination of trace amounts of dioxins in human milk and plasma. The initial temperature and the initial dwelling time of the inlet and the kind of solvent used were found to be critical in determining the analytical sensitivity of dioxins due to the loss of these relatively volatile compounds during solvent vaporization. Human milk and plasma were purified and fractionated by pre-packed multi-layered silica-gel chromatography and activated carbon silica-gel column chromatography. A 20-microL aliquot of the fraction collected from the chromatography with toluene was directly applied to the LVI system in high-resolution gas chromatography/high-resolution mass spectrometry. Excellent correlation (r > 0.97) between the values obtained by the LVI method using the SSIL device and those by the conventional regular-volume splitless injection method was obtained for PCDDs, PCDFs and non-ortho PCBs in human milk and plasma samples.

AUTOMATED ANALYSIS OF AQUEOUS SAMPLES CONTAINING PESTICIDES, ACIDIC/BASIC/NEUTRAL SEMIVOLATILES AND VOLATILE ORGANIC COMPOUNDS BY SOLID PHASE EXTRACTION COUPLED IN-LINE TO LARGE VOLUME INJECTION GC/MS

EPA Science Inventory

Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line 10-m...

Stackable differential mobility analyzer for aerosol measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Meng-Dawn; Chen, Da-Ren

2007-05-08

A multi-stage differential mobility analyzer (MDMA) for aerosol measurements includes a first electrode or grid including at least one inlet or injection slit for receiving an aerosol including charged particles for analysis. A second electrode or grid is spaced apart from the first electrode. The second electrode has at least one sampling outlet disposed at a plurality different distances along its length. A volume between the first and the second electrode or grid between the inlet or injection slit and a distal one of the plurality of sampling outlets forms a classifying region, the first and second electrodes for chargingmore » to suitable potentials to create an electric field within the classifying region. At least one inlet or injection slit in the second electrode receives a sheath gas flow into an upstream end of the classifying region, wherein each sampling outlet functions as an independent DMA stage and classifies different size ranges of charged particles based on electric mobility simultaneously.« less

Fused silica capillaries with two segments of different internal diameters and inner surface roughnesses prepared by etching with supercritical water and used for volume coupling electrophoresis.

PubMed

Horká, Marie; Karásek, Pavel; Roth, Michal; Šlais, Karel

2017-05-01

In this work, single-piece fused silica capillaries with two different internal diameter segments featuring different inner surface roughness were prepared by new etching technology with supercritical water and used for volume coupling electrophoresis. The concept of separation and online pre-concentration of analytes in high conductivity matrix is based on the online large-volume sample pre-concentration by the combination of transient isotachophoretic stacking and sweeping of charged proteins in micellar electrokinetic chromatography using non-ionogenic surfactant. The modified surface roughness step helped to the significant narrowing of the zones of examined analytes. The sweeping and separating steps were accomplished simultaneously by the use of phosphate buffer (pH 7) containing ethanol, non-ionogenic surfactant Brij 35, and polyethylene glycol (PEG 10000) after sample injection. Sample solution of a large volume (maximum 3.7 μL) dissolved in physiological saline solution was injected into the wider end of capillary with inlet inner diameter from 150, 185 or 218 μm. The calibration plots were linear (R 2 ∼ 0.9993) over a 0.060-1 μg/mL range for the proteins used, albumin and cytochrome c. The peak area RSDs from at least 20 independent measuremens were below 3.2%. This online pre-concentration technique produced a more than 196-fold increase in sensitivity, and it can be applied for detection of, e.g. the presence of albumin in urine (0.060 μg/mL). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A High-Performance Liquid Chromatography-Based Screening Method for the Analysis of Atrazine, Alachlor, and Ten of Their Transformation Products

USGS Publications Warehouse

Schroyer, B.R.; Capel, P.D.

1996-01-01

A high-performance liquid Chromatography (HPLC) method is presented for the for the fast, quantitative analysis of the target analytes in water and in low organic-carbon, sandy soils that are known to be contaminated with the parent herbicides. Speed and ease of sample preparation was prioritized above minimizing detection limits. Soil samples were extracted using 80:20 methanol:water (volume:volume). Water samples (50 ??L) were injected directly into the HPLC without prior preparation. Method quantification limits for soil samples (10 g dry weight) and water samples ranged from 20 to 110 ng/g and from 20 to 110 ??g/L for atrazine and its transformation products and from 80 to 320 ng/g and from 80 to 320 ??g/L for alachlor and its transformation products, respectively.

Determination of Total Petroleum Hydrocarbons in Australian Groundwater Through the Improvised Gas Chromatography-Flame Ionization Detection Technique.

PubMed

Faustorilla, Maria Vilma; Chen, Zuliang; Dharmarajan, Rajarathnam; Naidu, Ravendra

2017-09-01

Assessment of total petroleum hydrocarbons (TPHs) from contaminated sites demands routine and reliable measurement at trace levels. However, the detection limits of these methods need to be improved. This study developed the programmable temperature vaporization-large volume injection (PTV-LVI) method to quantify TPHs through gas chromatography-flame ionization detection. This configuration enhances the method sensitivity for trace level detections through large volume injections and pre-concentration of analytes along the injection liner. The method was evaluated for the three commonly observed hydrocarbon fractions: C10-C14, C15-C28 and C29-C36. In comparison with conventional injection methods (splitless and pulsed splitless), PTV-LVI showed R2 values > 0.999 with enhanced limits of detection and limits of quantification values. The method was applied to real samples for routine environmental monitoring of TPHs in an Australian contaminated site characterized by refueling station. Analysis of groundwater samples in the area showed a wide range of TPH concentrations as follows: 66-1,546,000 (C10-C14), 216-22,762 (C15-C28) and 105-2,103 (C29-C36) μg/L. This method has detected trace levels, thereby measuring a wider concentration range of TPHs. These more accurate measurements can lead to the appropriate application of risk assessments and remediation techniques. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Determination of Parabens by Injection-Port Derivatization Coupled With Gas-Chromatography-Mass Spectrometry and Matrix Solid Phase Dispersion

NASA Astrophysics Data System (ADS)

Djatmika, Rosalina; Ding, Wang-Hsien; Sulistyarti, Hermin

2018-01-01

A rapid determination of four parabens preservatives (methyl paraben, ethyl paraben, propyl paraben, and butyl paraben) in marketed seafood is presented. Analytes were extracted and purified using matrix solid-phase dispersion (MSPD) method, followed by Injection port acylation gas chromatography-mass spectrometry (GC-MS) with acetic anhydride reagent. In this method, acylation of parabens was performed by acetic anhydride at GC injection-port generating reduction of the time-consuming sample-processing steps, and the amount of toxic reagents and solvents. The parameters affecting this method such as injection port temperature, purge-off time and acylation (acetic anhydride) volume were studied. In addition, the MSPD influence factors (including the amount of dispersant and clean-up co-sorbent, as well as the volume of elution solvent) were also investigated. After MSPD method and Injection port acylation applied, good linearity of analytes was achieved. The limits of quantitation (LOQs) were 0.2 to 1.0 ng/g (dry weight). Compared with offline derivatization commonly performed, injection port acylation employs a rapid, simple, low-cost and environmental-friendly derivatization process. The optimized method has been successfully applied for the analysis of parabens in four kind of marketed seafood. Preliminary results showed that the total concentrations of four selected parabens ranged from 16.7 to 44.7 ng/g (dry weight).

Fiber Volume Fraction Influence on Fiber Compaction in Tapered Resin Injection Pultrusion Manufacturing

NASA Astrophysics Data System (ADS)

Masuram, N. B.; Roux, J. A.; Jeswani, A. L.

2016-06-01

Liquid resin is injected into the tapered injection chamber through the injection slots to completely wetout the fiber reinforcements in a resin injection pultrusion process. As the resin penetrates through the fibers, the resin also pushes the fibers away from the wall towards the centerline causing compaction of the fiber reinforcements. The fibers are squeezed together due to compaction, making resin penetration more difficult; thus higher resin injection pressures are required to effectively penetrate through the fibers and achieve complete wetout. Fiber volume fraction in the final pultruded composite is a key to decide the mechanical and/or chemical properties of the composite. If the fiber volume fraction is too high, more fibers are squeezed together creating a fiber lean region near the wall and fiber rich region away from the wall. Also, the design of the injection chamber significantly affects the minimum injection pressure required to completely wet the fibers. A tapered injection chamber is considered such that wetout occurs at lower injection pressures due to the taper angle of the injection chamber. In this study, the effect of fiber volume fraction on the fiber reinforcement compaction and complete fiber wetout for a tapered injection chamber is investigated.

Simultaneous determination of fluoroquinolones in environmental water by liquid chromatography-tandem mass spectrometry with direct injection: A green approach.

PubMed

Denadai, Marina; Cass, Quezia Bezerra

2015-10-30

This work describes an on-line multi-residue method for simultaneous quantification of ciprofloxacin, enrofloxacin, gemifloxacin, moxifloxacin, norfloxacin and ofloxacin in superficial and wastewater samples. For that, an octyl restricted-access media bovine serum albumin column (RAM-BSA C8) was used for sample clean-up, enrichment and analysis with quantitation carried out by tandem mass spectrometry. For water samples volumes of only 500μL the method provided good selectivity, extraction efficiency, accuracy, and precision with quantification limits in the order of 20-150ngL(-1). Out of the six fluoroquinolones only ciprofloxacin (195ngL(-1)) and norfloxacin (270ngL(-1)) were quantified in an influent sample of the wastewater treatment plant (WWTP) of São Carlos (SP, Brazil). None were found in the superficial water samples analyzed. The capability of injecting native sample in an automated mode provides high productivity and represents a greener approach in environmental sample analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

High sensitive analysis of steroids in doping control using gas chromatography/time-of-flight mass-spectrometry.

PubMed

Revelsky, A I; Samokhin, A S; Virus, E D; Rodchenkov, G M; Revelsky, I A

2011-04-01

The method of high sensitive gas chromatographic/time-of-flight mass-spectrometric (GC/TOF-MS) analysis of steroids was developed. Low-resolution TOF-MS instrument (with fast spectral acquisition rate) was used. This method is based on the formation of the silyl derivatives of steroids; exchange of the reagent mixture (pyridine and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)) for tert-butylmethylether; offline large sample volume injection of this solution based on sorption concentration of the respective derivatives from the vapour-gas mixture flow formed from the solution and inert gas flows; and entire analytes solvent-free concentrate transfer into the injector of the gas chromatograph. Detection limits for 100 µl sample solution volume were 0.5-2 pg/µl (depending on the component). Application of TOF-MS model 'TruTOF' (Leco, St Joseph, MO, USA) coupled with gas chromatograph and ChromaTOF software (Leco, St Joseph, MO, USA) allowed extraction of the full mass spectra and resolving coeluted peaks. Due to use of the proposed method (10 µl sample aliquot) and GC/TOF-MS, two times more steroid-like compounds were registered in the urine extract in comparison with the injection of 1 µl of the same sample solution. Copyright © 2010 John Wiley & Sons, Ltd.

Analysis of Androgenic Steroids in Environmental Waters by Large-volume Injection Liquid Chromatography Tandem Mass Spectrometry

PubMed Central

Backe, Will J.; Ort, Christoph; Brewer, Alex J.; Field, Jennifer A.

2014-01-01

A new method was developed for the analysis of natural and synthetic androgenic steroids and their selected metabolites in aquatic environmental matrices using direct large-volume injection (LVI) high performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). Method accuracy ranged from 88 to 108% for analytes with well-matched internal standards. Precision, quantified by relative standard deviation (RSD), was less than 12%. Detection limits for the method ranged from 1.2 to 360 ng/L. The method was demonstrated on a series of 1-hr composite wastewater influent samples collected over a day with the purpose of assessing temporal profiles of androgen loads in wastewater. Testosterone, androstenedione, boldenone, and nandrolone were detected in the sample series at concentrations up to 290 ng/L and loads up to 535 mg. Boldenone, a synthetic androgen, had a temporal profile that was strongly correlated to testosterone, a natural human androgen, suggesting its source may be endogenous. An analysis of the sample particulate fraction revealed detectable amounts of sorbed testosterone and androstenedione. Androstenedione sorbed to the particulate fraction accounted for an estimated five to seven percent of the total androstenedione mass. PMID:21391574

Analysis of androgenic steroids in environmental waters by large-volume injection liquid chromatography tandem mass spectrometry.

PubMed

Backe, Will J; Ort, Christoph; Brewer, Alex J; Field, Jennifer A

2011-04-01

A new method was developed for the analysis of natural and synthetic androgenic steroids and their selected metabolites in aquatic environmental matrixes using direct large-volume injection (LVI) high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). Method accuracy ranged from 87.6 to 108% for analytes with well-matched internal standards. Precision, quantified by relative standard deviation (RSD), was less than 12%. Detection limits for the method ranged from 1.2 to 360 ng/L. The method was demonstrated on a series of 1 h composite wastewater influent samples collected over a day with the purpose of assessing temporal profiles of androgen loads in wastewater. Testosterone, androstenedione, boldenone, and nandrolone were detected in the sample series at concentrations up to 290 ng/L and loads up to 535 mg/h. Boldenone, a synthetic androgen, had a temporal profile that was strongly correlated to testosterone, a natural human androgen, suggesting its source may be endogenous. An analysis of the sample particulate fraction revealed detectable amounts of sorbed testosterone and androstenedione. Androstenedione sorbed to the particulate fraction accounted for an estimated 5 to 7% of the total androstenedione mass.

Micro-injector for capillary electrophoresis.

PubMed

Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C

2015-08-01

A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 μm diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A device for controlled jet injection of large volumes of liquid.

PubMed

Mckeage, James W; Ruddy, Bryan P; Nielsen, Poul M F; Taberner, Andrew J

2016-08-01

We present a needle-free jet injection device controllably actuated by a voice coil and capable of injecting up to 1.3 mL. This device is used to perform jet injections of ~900 μL into porcine tissue. This is the first time that delivery of such a large volume has been reported using an electronically controllable device. The controllability of this device is demonstrated with a series of ejections where the desired volume is ejected to within 1 % during an injection at a predetermined jet velocity.

Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, Deepak; Kertesz, Vilmos; Van Berkel, Gary J

RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injectionmore » volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.« less

Effect of Water Invasion on Outburst Predictive Index of Low Rank Coals in Dalong Mine

PubMed Central

Jiang, Jingyu; Cheng, Yuanping; Mou, Junhui; Jin, Kan; Cui, Jie

2015-01-01

To improve the coal permeability and outburst prevention, coal seam water injection and a series of outburst prevention measures were tested in outburst coal mines. These methods have become important technologies used for coal and gas outburst prevention and control by increasing the external moisture of coal or decreasing the stress of coal seam and changing the coal pore structure and gas desorption speed. In addition, techniques have had a significant impact on the gas extraction and outburst prevention indicators of coal seams. Globally, low rank coals reservoirs account for nearly half of hidden coal reserves and the most obvious feature of low rank coal is the high natural moisture content. Moisture will restrain the gas desorption and will affect the gas extraction and accuracy of the outburst prediction of coals. To study the influence of injected water on methane desorption dynamic characteristics and the outburst predictive index of coal, coal samples were collected from the Dalong Mine. The methane adsorption/desorption test was conducted on coal samples under conditions of different injected water contents. Selective analysis assessed the variations of the gas desorption quantities and the outburst prediction index (coal cutting desorption index). Adsorption tests indicated that the Langmuir volume of the Dalong coal sample is ~40.26 m3/t, indicating a strong gas adsorption ability. With the increase of injected water content, the gas desorption amount of the coal samples decreased under the same pressure and temperature. Higher moisture content lowered the accumulation desorption quantity after 120 minutes. The gas desorption volumes and moisture content conformed to a logarithmic relationship. After moisture correction, we obtained the long-flame coal outburst prediction (cutting desorption) index critical value. This value can provide a theoretical basis for outburst prediction and prevention of low rank coal mines and similar occurrence conditions of coal seams. PMID:26161959

Characterization and optimization of low cost microfluidic thread based electroanalytical device for micro flow injection analysis.

PubMed

Agustini, Deonir; Bergamini, Márcio F; Marcolino-Junior, Luiz Humberto

2017-01-25

The micro flow injection analysis (μFIA) is a powerful technique that uses the principles of traditional flow analysis in a microfluidic device and brings a number of improvements related to the consumption of reagents and samples, speed of analysis and portability. However, the complexity and cost of manufacturing processes, difficulty in integrating micropumps and the limited performance of systems employing passive pumps are challenges that must be overcome. Here, we present the characterization and optimization of a low cost device based on cotton threads as microfluidic channel to perform μFIA based on passive pumps with good analytical performance in a simple, easy and inexpensive way. The transport of solutions is made through cotton threads by capillary force facilitated by gravity. After studying and optimizing several features related to the device, were obtained a flow rate of 2.2 ± 0.1 μL s -1 , an analytical frequency of 208 injections per hour, a sample injection volume of 2.0 μL and a waste volume of approximately 40 μL per analysis. For chronoamperometric determination of naproxen, a detection limit of 0.29 μmol L -1 was reached, with a relative standard deviation (RSD) of 1.69% between injections and a RSD of 3.79% with five different devices. Thus, based on the performance presented by proposed microfluidic device, it is possible to overcome some limitations of the μFIA systems based on passive pumps and allow expansion in the use of this technique. Copyright © 2016 Elsevier B.V. All rights reserved.

A simple dual online ultra-high pressure liquid chromatography system (sDO-UHPLC) for high throughput proteome analysis.

PubMed

Lee, Hangyeore; Mun, Dong-Gi; Bae, Jingi; Kim, Hokeun; Oh, Se Yeon; Park, Young Soo; Lee, Jae-Hyuk; Lee, Sang-Won

2015-08-21

We report a new and simple design of a fully automated dual-online ultra-high pressure liquid chromatography system. The system employs only two nano-volume switching valves (a two-position four port valve and a two-position ten port valve) that direct solvent flows from two binary nano-pumps for parallel operation of two analytical columns and two solid phase extraction (SPE) columns. Despite the simple design, the sDO-UHPLC offers many advantageous features that include high duty cycle, back flushing sample injection for fast and narrow zone sample injection, online desalting, high separation resolution and high intra/inter-column reproducibility. This system was applied to analyze proteome samples not only in high throughput deep proteome profiling experiments but also in high throughput MRM experiments.

Feasibility of corona discharge ion mobility spectrometry for direct analysis of samples extracted by dispersive liquid-liquid microextraction.

PubMed

Jafari, Mohammad T; Riahi, Farhad

2014-05-23

The capability of corona discharge ionization ion mobility spectrometry (CD-IMS) for direct analysis of the samples extracted by dispersive liquid-liquid microextraction (DLLME) was investigated and evaluated, for the first time. To that end, an appropriate new injection port was designed and constructed, resulting in possibility of direct injection of the known sample volume, without tedious sample preparation steps (e.g. derivatization, solvent evaporation, and re-solving in another solvent…). Malathion as a test compound was extracted from different matrices by a rapid and convenient DLLME method. The positive ion mobility spectra of the extracted malathion were obtained after direct injection of carbon tetrachloride or methanol solutions. The analyte responses were compared and the statistical results revealed the feasibility of direct analysis of the extracted samples in carbon tetrachloride, resulting in a convenient methodology. The coupled method of DLLME-CD-IMS was exhaustively validated in terms of sensitivity, dynamic range, recovery, and enrichment factor. Finally, various real samples of apple, river and underground water were analyzed, all verifying the feasibility and success of the proposed method for the easy extraction of the analyte using DLLME separation before the direct analysis by CD-IMS. Copyright © 2014 Elsevier B.V. All rights reserved.

Using the fundamentals of adsorption to understand peak distortion due to strong solvent effect in hydrophilic interaction chromatography.

PubMed

Gritti, Fabrice; Sehajpal, Jyotsna; Fairchild, Jacob

2017-03-17

The peak distortion observed in hydrophilic interaction chromatography (HILIC) may be caused by the sample diluent to mobile phase mismatch. The United States Pharmacopeia (USP) method for organic impurities in cetirizine HCl tablets calls for such a mismatch, having a higher concentration of strong solvent in the sample diluent than in the mobile phase. A significant peak deformation is reported for cetirizine (a second-generation antihistamine) when it is purified on a Ethylene Bridged Hybrid (BEH) HILIC column (4.6mm×100mm, 2.5μm particles) using an acetonitrile-water eluent mixture and a sample diluent containing 7% and 9% water (in volume), respectively. The mechanism and physical origin of such peak distortion are related to (1) the diluent-to-eluent excess of water that propagates along the column at a velocity similar to that of the analyte, (2) the significant drop of the Henry's constant of the analyte upon increasing water concentration in the eluent, (3) the sample volume injected, and (4) to the pre-column sample dilution factor that depends on the characteristics of the LC instrument used. This proposed mechanism is validated from the calculation of the concentration profiles of cetirizine and water by using the equilibrium-dispersive (ED) model of chromatography. The observed distortion of cetirizine peaks is successfully predicted from the measurement of (1) the excess adsorption isotherm of water from acetonitrile onto the BEH HILIC adsorbent, (2) the retention factor of cetirizine as a function of the volume fraction (7, 8, and 9%) of water in the mobile phase, and (3) of the pre-column sample dispersion related to the instrument used (HPLC or UHPLC). The results of the calculations enables the user to anticipate the impacts of the diluent-to-eluent mismatch in water content, the injection volume, the analyte retention under infinite dilution, and of the pre-column sample dispersion on the amplitude of peak distortion in HILIC. Appropriate and permitted alterations of the USP method are then suggested based on a sound physico-chemical approach. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a bar adsorptive micro-extraction-large-volume injection-gas chromatography-mass spectrometric method for pharmaceuticals and personal care products in environmental water matrices.

PubMed

Neng, N R; Nogueira, J M F

2012-01-01

The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L(-1)) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics: pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%), convenient detection limits (5-20 ng L(-1)) and excellent linear dynamic range (20-800 ng L(-1)) with remarkable determination coefficients (r(2) > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor PPCPs in water matrices.

A METHOD FOR AUTOMATED ANALYSIS OF 10 ML WATER SAMPLES CONTAINING ACIDIC, BASIC, AND NEUTRAL SEMIVOLATILE COMPOUNDS LISTED IN USEPA METHOD 8270 BY SOLID PHASE EXTRACTION COUPLED IN-LINE TO LARGE VOLUME INJECTION GAS CHROMATOGRAPHY/MASS SPECTROMETRY

EPA Science Inventory

Data is presented showing the progress made towards the development of a new automated system combining solid phase extraction (SPE) with gas chromatography/mass spectrometry for the single run analysis of water samples containing a broad range of acid, base and neutral compounds...

Capillary ion chromatography with on-column focusing for ultra-trace analysis of methanesulfonate and inorganic anions in limited volume Antarctic ice core samples.

PubMed

Rodriguez, Estrella Sanz; Poynter, Sam; Curran, Mark; Haddad, Paul R; Shellie, Robert A; Nesterenko, Pavel N; Paull, Brett

2015-08-28

Preservation of ionic species within Antarctic ice yields a unique proxy record of the Earth's climate history. Studies have been focused until now on two proxies: the ionic components of sea salt aerosol and methanesulfonic acid. Measurement of the all of the major ionic species in ice core samples is typically carried out by ion chromatography. Former methods, whilst providing suitable detection limits, have been based upon off-column preconcentration techniques, requiring larger sample volumes, with potential for sample contamination and/or carryover. Here, a new capillary ion chromatography based analytical method has been developed for quantitative analysis of limited volume Antarctic ice core samples. The developed analytical protocol applies capillary ion chromatography (with suppressed conductivity detection) and direct on-column sample injection and focusing, thus eliminating the requirement for off-column sample preconcentration. This limits the total sample volume needed to 300μL per analysis, allowing for triplicate sample analysis with <1mL of sample. This new approach provides a reliable and robust analytical method for the simultaneous determination of organic and inorganic anions, including fluoride, methanesulfonate, chloride, sulfate and nitrate anions. Application to composite ice-core samples is demonstrated, with coupling of the capillary ion chromatograph to high resolution mass spectrometry used to confirm the presence and purity of the observed methanesulfonate peak. Copyright © 2015 Elsevier B.V. All rights reserved.

nZVI injection into variably saturated soils: Field and modeling study

NASA Astrophysics Data System (ADS)

Chowdhury, Ahmed I. A.; Krol, Magdalena M.; Kocur, Christopher M.; Boparai, Hardiljeet K.; Weber, Kela P.; Sleep, Brent E.; O'Carroll, Denis M.

2015-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI field-scale mobility. In this study, a field test was combined with numerical modeling to examine nZVI reactivity along with transport properties in variably saturated soils. The field test consisted of 142 L of carboxymethyle cellulose (CMC) stabilized monometallic nZVI synthesized onsite and injected into a variably saturated zone. Periodic groundwater samples were collected from the injection well, as well as, from two monitoring wells to analyze for chlorinated solvents and other geochemistry indicators. This study showed that CMC stabilized monometallic nZVI was able to decrease tricholorethene (TCE) concentrations in groundwater by more than 99% from the historical TCE concentrations. A three dimensional, three phase, finite difference numerical simulator, (CompSim) was used to further investigate nZVI and polymer transport at the variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the mass of nZVI delivered to the saturated and unsaturated zones and distinguished the nZVI phase (i.e. aqueous or attached). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity and viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher nZVI volume delivered more iron particles at a given distance; however, the travel distance was not proportional to the increase in volume. Moreover, simulation results showed that using a 1D transport equation to simulate nZVI migration in the subsurface may overestimate the travel distance. This is because the 1D transport equation assumes a constant velocity while pore water velocity radially decreases from the well during injection. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and that a numerical simulator can be a valuable tool for optimal design of nZVI field applications.

A micro-fluidic sub-microliter sample introduction system for direct analysis of Chinese rice wine by inductively coupled plasma mass spectrometry using external aqueous calibration

NASA Astrophysics Data System (ADS)

Cheng, Heyong; Liu, Jinhua; Xu, Zigang; Yin, Xuefeng

2012-07-01

A microfluidic sub-microliter sample introducing system was developed for direct analysis of Chinese rice wine by inductively coupled plasma mass spectrometry (ICP-MS). It consisted of a microfluidic chip integrating variable-volume sampling channels (0.1-0.8 μL), an eight-way multi-functional valve used in flow injection analysis (FIA), a syringe pump and a peristaltic pump of the Ar ICP-MS instrument. Three solutions, i.e., 15, 40 and 100 g L- 1 glucose in 20% ethanol were used to simulate Chinese rice wine of the dry type, the semidry type and the semisweet type, each. The effects of their volume introduced into ICP-MS on the plasma stability and ICP-MS intensities were studied. The experimental results showed that neither alteration of plasma stability nor carbon deposition was observed when the sampling volume of 20% ethanol containing 100 g L- 1 glucose was downscaled to 0.8 μL. Further reducing the sampling volume to 0.4 μL, no significant difference between the intensities of multi-element standard prepared in three simulated Chinese rice wine matrices and those in aqueous solution was observed. It indicated no negative effect of Chinese rice wine matrix on the ICP-MS intensities. A sampling volume of 0.4 μL was considered to be a good compromise between sensitivity and matrix effect. The flow rate of the carrier was chosen as 20 μL min- 1 for obtaining peaks with the highest peak height within the shortest time. Based on these observations, a microflow injection (μFI) method for the direct determination of cadmium and lead in Chinese rice wine by ICP-MS using an external aqueous calibration was developed. The sample throughput was 45 h- 1 with the detection limit of 19.8 and 10.4 ng L- 1 for Cd and Pb, respectively. The contents of Cd and Pb in 10 Chinese rice wine samples were measured. The results agreed well with those determined by ICP-MS with the conventional sampling system after microwave assisted digestion. The recoveries of three Chinese rice wine samples ranged between 95.5 and 102.8%. Furthermore, the determined contents of Cd and Pb in a certified reference material of red wine (GBW 10031) and a quality control test material of wine (FAPAS T07163QC) by the proposed method were in fairly good accordance with the certified/assigned values. All results verified the accuracy of our method.

A study for the installation of the TEXT heavy-ion beam probe on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmonds, P.H.; Solano, E.R.; Bravenec, R.V.

1997-01-01

An assessment of the feasibility of installing the TEXT 2 MeV heavy-ion beam probe on the DIII-D tokamak has been completed. Detailed drawings of the machine cross section were imported into the CAD application AutoCAD. A set of programs written in AutoLisp were used to generate trajectories. Displays of the accessible cross section of the plasma, scan lines for the entire range of primary beam energy and injection angle ranges, and sample{endash}volume dimensions can be rapidly generated. Because of the large deflection between the primary input beam and the emergent secondary beam, either the analyzer needs to be tracked overmore » a {plus_minus}20{degree} angle or secondary poloidal deflector plates need to be installed at the exit port. Toroidal deflector plates will be installed at both the injection and exit ports to compensate for toroidal displacements and deflections. The sample volumes generated by this procedure are within a few centimeters of the locations derived from a full three-dimensional calculation.{copyright} {ital 1997 American Institute of Physics.}« less

Extraforaminal needle tip position reduces risk of intravascular injection in CT-fluoroscopic lumbar transforaminal epidural steroid injections

PubMed Central

Yu, Robinson K.; Ghodadra, Anish; Agarwal, Vikas

2016-01-01

Background Lumbar transforaminal epidural steroid injection is a common and effective tool for managing lumbar radicular pain, although accidental intravascular injection can rarely result in paralysis. The purpose of this study is to determine the safest needle tip position for computed tomography (CT)-guided lumbar transforaminal epidural steroid injections as determined by incidence of intravascular injection. Methods Three radiologists, in consensus, reviewed procedural imaging for consecutive CT-fluoroscopic lumbar transforaminal epidural steroid injections performed during a 16-month period. Intravascular injections were identified and categorized by needle tip position, vessel type injected, intravascular injection volume and procedural phase containing the intravascular injection. Pearson chi-square and logistic regression testing were used to assess differences between groups, as appropriate. Results Intravascular injections occurred in 9% (52/606) of injections. The intravascular injection rate was significantly lower (P<0.001) for extraforaminal needle position (0%, 0/109) compared to junctional (8%, 27/319) and foraminal (14%, 25/178) needle tip positions. Of the intravascular injections, 4% (2/52) were likely arterial, 35% (18/52) were likely venous, and 62% (32/52) were indeterminate for vessel type injected. 46% (24/52) of intravascular injections were large volume, 33% (17/52) were small volume, and 21% (11/52) were trace volume. 56% (29/52) of intravascular injections occurred with the contrast trial dose, 29% (15/52) with the steroid/analgesic cocktail, and 15% (8/52) with both. Conclusions An extraforaminal needle position for CT-fluoroscopic lumbar transforaminal epidural steroid injections decreases the risk of intravascular injection and therefore may be safer than other needle tip positions. PMID:28097241

Accuracy and reproducibility of the measurement of actively circulating blood volume with an integrated fiberoptic monitoring system.

PubMed

Kisch, H; Leucht, S; Lichtwarck-Aschoff, M; Pfeiffer, U J

1995-05-01

Bedside monitoring of circulating blood volume has become possible with the introduction of an integrated fiberoptic monitoring system that calculates blood volume from the changes in blood concentration of indocyanine green dye 4 mins after injection. The aim of this investigation was to compare the blood volume estimate of the integrated fiberoptic monitoring system (group 1) with the standard methods of blood volume measurement using Evans blue (group 2), and indocyanine green measured photometrically (group 3). Prospective laboratory study. Animal laboratory of a University's institute for experimental surgery. Eleven anesthetized, paralyzed, and mechanically ventilated piglets. A central venous catheter was used for the injection of the indicator dyes (Evans blue and indocyanine green). A fiberoptic thermistor catheter was advanced into the thoracic aorta. The fiberoptic catheter detects indocyanine green by reflection densitometry for the estimation of blood volume of the integrated fiberoptic monitoring system. Samples for the determination of Evans blue and indocyanine green concentrations were drawn from an arterial catheter in the femoral artery over a period of 17 mins after injection. Measurements were performed during normovolemia, hypovolemia (blood withdrawal of < or = 30 mL/kg), and hypervolemia (retransfusion of the withdrawn blood plus an infusion of 10% hydroxyethyl starch [45 mL/kg]). Linear regression, correlation, and bias were calculated for the comparison of the blood volume estimates by the fiberoptic monitoring system (group 1) vs. the total blood volume estimates using Evans blue (group 2) and indocyanine green (group 3): group 1 = 0.82.group 2-26 mL; r2 = 82.71%; r = .91; n = 40; group 1-group 2 +/- 1 SD = -435 +/- 368 mL; group 1 = 0.79.group 3 + 50 mL; r2 = 74.81%; r = .87; n = 28; group 1-group 3 +/- 1 SD = -506 +/- 374 mL. The results demonstrate that the blood volume estimate of the fiberoptic monitoring system (group 1) correlates closely with the total blood volume measurement using Evans blue (group 2) and indocyanine green (group 3). Trapped indicator in the packed red cell column after centrifugation of the blood samples may account for an overestimation of group 2 and group 3 of approximately 10% to 14%, but there still remains a proportional difference of 10% between group 1 vs. group 2 and vs. group 3. This difference is due to the longer mixing times of group 3 (16 mins) and group 2 (17 mins), during which they are distributed in slowly exchanging blood pools. It seems that the blood volume estimate of the fiberoptic monitoring system (group 1) represents the actively circulating blood volume and may be useful for bedside monitoring.

Anthropogenic seismicity rates and operational parameters at the Salton Sea Geothermal Field.

PubMed

Brodsky, Emily E; Lajoie, Lia J

2013-08-02

Geothermal power is a growing energy source; however, efforts to increase production are tempered by concern over induced earthquakes. Although increased seismicity commonly accompanies geothermal production, induced earthquake rate cannot currently be forecast on the basis of fluid injection volumes or any other operational parameters. We show that at the Salton Sea Geothermal Field, the total volume of fluid extracted or injected tracks the long-term evolution of seismicity. After correcting for the aftershock rate, the net fluid volume (extracted-injected) provides the best correlation with seismicity in recent years. We model the background earthquake rate with a linear combination of injection and net production rates that allows us to track the secular development of the field as the number of earthquakes per fluid volume injected decreases over time.

Fast cholesterol detection using flow injection microfluidic device with functionalized carbon nanotubes based electrochemical sensor.

PubMed

Wisitsoraat, A; Sritongkham, P; Karuwan, C; Phokharatkul, D; Maturos, T; Tuantranont, A

2010-12-15

This work reports a new cholesterol detection scheme using functionalized carbon nanotube (CNT) electrode in a polydimethylsiloxane/glass based flow injection microfluidic chip. CNTs working, silver reference and platinum counter electrode layers were fabricated on the chip by sputtering and low temperature chemical vapor deposition methods. Cholesterol oxidase prepared in polyvinyl alcohol solution was immobilized on CNTs by in-channel flow technique. Cholesterol analysis based on flow injection chronoamperometric measurement was performed in 150-μm-wide and 150-μm-deep microchannels. Fast and sensitive real-time detection was achieved with high throughput of more than 60 samples per hour and small sample volume of 15 μl. The cholesterol sensor had a linear detection range between 50 and 400 mg/dl. In addition, low cross-sensitivities toward glucose, ascorbic acid, acetaminophen and uric acid were confirmed. The proposed system is promising for clinical diagnostics of cholesterol with high speed real-time detection capability, very low sample consumption, high sensitivity, low interference and good stability. Copyright © 2010 Elsevier B.V. All rights reserved.

A morphological evaluation of botulinum neurotoxin A injections into the detrusor muscle using magnetic resonance imaging.

PubMed

Mehnert, Ulrich; Boy, Sönke; Schmid, Marius; Reitz, André; von Hessling, Alexander; Hodler, Juerg; Schurch, Brigitte

2009-06-01

Although botulinum neurotoxin type A (BoNT/A) intradetrusor injections are a recommended therapy for neurogenic detrusor overactivity (NDO), refractory to antimuscarinic drugs, a standardisation of injection technique is missing. Furthermore, some basic questions are still unanswered, as where the toxin solution exactly spreads after injection. Therefore, we investigated the distribution of the toxin solution after injection into the bladder wall, using magnet resonance imaging (MRI). Six patients with NDO were recruited. Three of six patients received 300 U of BoNT/A + contrast agent distributed over 30 injection sites (group 1). The other three patients received 300 U of BoNT/A + contrast agent distributed over 10 injection sites (group 2). Immediately after injection, MRI of the pelvis was performed. The volume of the detrusor and the total volume of contrast medium inside and outside the bladder wall were calculated. In all patients, a small volume (mean 17.6%) was found at the lateral aspects of the bladder dome in the extraperitoneal fat tissue, whereas 82.4% of the injected volume reached the target area (detrusor). In both groups there was a similar distribution of the contrast medium in the target area. A mean of 33.3 and 25.3% of the total detrusor volume was covered in group 1 and 2, respectively. Six weeks after injection, five of six patients were continent and showed no detrusor overactivity in the urodynamic follow-up. No systemic side effects were observed. Our results provide morphological arguments that the currently used injection techniques are appropriate and safe.

Estimation of CO2 saturation during both CO2 drainage and imbibition processes based on both seismic velocity and electrical resistivity measurements

NASA Astrophysics Data System (ADS)

Kim, Jongwook; Nam, Myung Jin; Matsuoka, Toshifumi

2013-10-01

In order to monitor injected carbon dioxide (CO2), simultaneous measurements of seismic velocity and electrical resistivity are employed during the drainage (CO2 injection) and imbibition (water injection) processes of a Berea sandstone. Supercritical CO2 (10 MPa at 40 ºC) was injected into a water-saturated Berea sandstone in the drainage stage and monitored via simultaneous measurements. After the injection of supercritical CO2, fresh distilled water was injected into the CO2-injected sandstone during the imbibition stage. Electrical resistivity and P-wave velocity measurements acquired during the drainage and imbibition stages were employed to evaluate CO2 saturations (SCO2) based on the resistivity index and the Gassmann fluid-substitution equations, respectively. Comparing estimated values for SCO2 saturation against those from volume-derived SCO2, based on analysis on injected and drained fluid volumes in the drainage process, we conclude that Gassmann-Brie and resistivity index are suitable for the evaluation based on P-wave velocity and electrical resistivity, respectively. Rt-based estimation properly tracks the variation in SCO2 even when SCO2 is large (>0.15), while Vp-based estimation is sensitive to the variation in SCO2 when SCO2 is small (<0.1). Employing the Gassmann-Brie and resistivity index, estimation of variation in SCO2 based on the simultaneous measurements provides the upper and lower bounds of SCO2 even when SCO2 is large (>0.1), while properly estimating SCO2 when SCO2 is small (<0.1). Monitoring the CO2 imbibition process confirms residual CO2 saturation within the sample.

Fracking, fracture, and permeability

NASA Astrophysics Data System (ADS)

Turcotte, D. L.; Norris, J.; Rundle, J. B.

2013-12-01

Injections of large volumes of water into tight shale reservoirs allows the extraction of oil and gas not previously accessible. This large volume 'super' fracking induces damage that allows the oil and/or gas to flow to an extraction well. The purpose of this paper is to provide a model for understanding super fracking. We assume that water is injected from a small spherical cavity into a homogeneous elastic medium. The high pressure of the injected water generates hoop stresses that reactivate natural fractures in the tight shales. These fractures migrate outward as water is added creating a spherical shell of damaged rock. The porosity associated with these fractures is equal to the water volume injected. We obtain an analytic expression for this volume. We apply our model to a typical tight shale reservoir and show that the predicted water volumes are in good agreement with the volumes used in super fracking.

Estimation of the sensitive volume for gravitational-wave source populations using weighted Monte Carlo integration

NASA Astrophysics Data System (ADS)

Tiwari, Vaibhav

2018-07-01

The population analysis and estimation of merger rates of compact binaries is one of the important topics in gravitational wave astronomy. The primary ingredient in these analyses is the population-averaged sensitive volume. Typically, sensitive volume, of a given search to a given simulated source population, is estimated by drawing signals from the population model and adding them to the detector data as injections. Subsequently injections, which are simulated gravitational waveforms, are searched for by the search pipelines and their signal-to-noise ratio (SNR) is determined. Sensitive volume is estimated, by using Monte-Carlo (MC) integration, from the total number of injections added to the data, the number of injections that cross a chosen threshold on SNR and the astrophysical volume in which the injections are placed. So far, only fixed population models have been used in the estimation of binary black holes (BBH) merger rates. However, as the scope of population analysis broaden in terms of the methodologies and source properties considered, due to an increase in the number of observed gravitational wave (GW) signals, the procedure will need to be repeated multiple times at a large computational cost. In this letter we address the problem by performing a weighted MC integration. We show how a single set of generic injections can be weighted to estimate the sensitive volume for multiple population models; thereby greatly reducing the computational cost. The weights in this MC integral are the ratios of the output probabilities, determined by the population model and standard cosmology, and the injection probability, determined by the distribution function of the generic injections. Unlike analytical/semi-analytical methods, which usually estimate sensitive volume using single detector sensitivity, the method is accurate within statistical errors, comes at no added cost and requires minimal computational resources.

A dispersive liquid--liquid microextraction methodology for copper (II) in environmental samples prior to determination using microsample injection flame atomic absorption spectrometry.

PubMed

Alothman, Zeid A; Habila, Mohamed; Yilmaz, Erkan; Soylak, Mustafa

2013-01-01

A simple, environmentally friendly, and efficient dispersive liquid-liquid microextraction method combined with microsample injection flame atomic absorption spectrometry was developed for the separation and preconcentration of Cu(II). 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) was used to form a hydrophobic complex of Cu(II) ions in the aqueous phase before extraction. To extract the Cu(II)-5-Br-PADAP complex from the aqueous phase to the organic phase, 2.0 mL of acetone as a disperser solvent and 200 microL of chloroform as an extraction solvent were used. The influences of important analytical parameters, such as the pH, types and volumes of the extraction and disperser solvents, amount of chelating agent, sample volume, and matrix effects, on the microextraction procedure were evaluated and optimized. Using the optimal conditions, the LOD, LOQ, preconcentration factor, and RSD were determined to be 1.4 microg/L, 4.7 microg/L, 120, and 6.5%, respectively. The accuracy of the proposed method was investigated using standard addition/recovery tests. The analysis of certified reference materials produced satisfactory analytical results. The developed method was applied for the determination of Cu in real samples.

Silicone rod extraction followed by liquid desorption-large volume injection-programmable temperature vaporiser-gas chromatography-mass spectrometry for trace analysis of priority organic pollutants in environmental water samples.

PubMed

Delgado, Alejandra; Posada-Ureta, Oscar; Olivares, Maitane; Vallejo, Asier; Etxebarria, Nestor

2013-12-15

In this study a priority organic pollutants usually found in environmental water samples were considered to accomplish two extraction and analysis approaches. Among those compounds organochlorine compounds, pesticides, phthalates, phenols and residues of pharmaceutical and personal care products were included. The extraction and analysis steps were based on silicone rod extraction (SR) followed by liquid desorption in combination with large volume injection-programmable temperature vaporiser (LVI-PTV) and gas chromatography-mass spectrometry (GC-MS). Variables affecting the analytical response as a function of the programmable temperature vaporiser (PTV) parameters were firstly optimised following an experimental design approach. The SR extraction and desorption conditions were assessed afterwards, including matrix modification, time extraction, and stripping solvent composition. Subsequently, the possibility of performing membrane enclosed sorptive coating extraction (MESCO) as a modified extraction approach was also evaluated. The optimised method showed low method detection limits (3-35 ng L(-1)), acceptable accuracy (78-114%) and precision values (<13%) for most of the studied analytes regardless of the aqueous matrix. Finally, the developed approach was successfully applied to the determination of target analytes in aqueous environmental matrices including estuarine and wastewater samples. © 2013 Elsevier B.V. All rights reserved.

Analysis of selected antibiotics in surface freshwater and seawater using direct injection in liquid chromatography electrospray ionization tandem mass spectrometry.

PubMed

Bayen, Stéphane; Yi, Xinzhu; Segovia, Elvagris; Zhou, Zhi; Kelly, Barry C

2014-04-18

Emerging contaminants such as antibiotics have received recent attention as they have been detected in natural waters and health concerns over potential antibiotic resistance. With the purpose to investigate fast and high-throughput analysis, and eventually the continuous on-line analysis of emerging contaminants, this study presents results on the analysis of seven selected antibiotics (sulfadiazine, sulfamethazine, sulfamerazine, sulfamethoxazole, chloramphenicol, lincomycin, tylosin) in surface freshwater and seawater using direct injection of a small sample volume (20μL) in liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Notably, direct injection of seawater in the LC-ESI-MS/MS was made possible on account of the post-column switch on the system, which allows diversion of salt-containing solutions flushed out of the column to the waste. Mean recoveries based on the isotope dilution method average 95±14% and 96±28% amongst the compounds for spiked freshwater and seawater, respectively. Linearity across six spiking levels was assessed and the response was linear (r(2)>0.99) for all compounds. Direct injection concentrations were compared for real samples to those obtained with the conventional SPE-based analysis and both techniques concurs on the presence/absence and levels of the compounds in real samples. These results suggest direct injection is a reliable method to detect antibiotics in both freshwater and seawater. Method detection limits for the direct injection technique (37pg/L to 226ng/L in freshwater, and from 16pg/to 26ng/L in seawater) are sufficient for a number of environmental applications, for example the fast screening of water samples for ecological risk assessments. In the present study of real samples, this new method allowed for example the positive detection of some compounds (e.g. lincomycin) down to the sub ng/L range. The direct injection method appears to be relatively cheaper and faster, requires a smaller sample size, and is more robust to equipment cross-contamination as compared to the conventional SPE-based method. Copyright © 2014 Elsevier B.V. All rights reserved.

The effects of lauromacrogol injection into rat endometrial cysts: a preliminary experimental study.

PubMed

Liu, Wei; Wang, LongXia; Guo, Cui-Xia

2016-09-01

To determine the effectiveness of different concentrations of lauromacrogol injections for the treatment of endometriosis in an experimental animal model and to provide an experimental basis for a pre-clinical application of the drug. After autologous transplantation of endometrial tissue, 40 endometrial cysts were successfully established and randomly divided into three groups: a 1 % lauromacrogol injection group, a 0.5 % lauromacrogol injection group, and cysts without intervention (control group). We measured the changes in the volumes of the cysts in each group. We then compared the volumes of the endometrial implants before and after treatment and between the different groups and examined the histological findings. A significant difference in the spherical volume was found between the 1 % lauromacrogol injection group (P < 0.05). No significant difference was observed between the volume of the endometrial implants in the 0.5 % lauromacrogol injection group (P > 0.05). Regarding the histopathological observations, in the 1 % lauromacrogol injection group, the epithelia of the cystic implants had atrophied, and the glands had atrophied and were reduced in number. The surrounding stromal tissue had become loose and edematous. A 1 % lauromacrogol injection produced significant regression of the endometrial foci compared with a 0.5 % lauromacrogol injection or no treatment in a rat model of endometriosis.

Experiment Research of Microbial Flooding Injected Capacity and Injected Volume

NASA Astrophysics Data System (ADS)

Shi, Fang; Zhao, Yang; Tang, Qinghua; Xie, Ximing

2018-01-01

Strains of microbial enhanced oil recovery technology is the use of crude oil directly in growth and the same time the metabolites of itself, so as to enhance oil recovery. Experimental study on paper through a number of data analysis. The growth and metabolism of three kinds of oil producing bacteria in the core are determined, and the corresponding growth curve is obtained. The parameter sensitivity analysis of the microorganism flooding process by homogeneous core is studied, and the influence of injection capacity and injection volume on the oil displacement effect is studied. The same permeability, water, temperature and other conditions, microbial injection pressure has a certain degree of increase than water flooding. Injection volume depends on the actual input-output ratio, quantity is 0.3PV is more reasonable.

Three-Dimensional Changes in the Midface Following Malar Calcium Hydroxyapatite Injection in a Cadaver Model.

PubMed

Gatherwright, James R; Brown, Matthew S; Katira, Kristopher M; Rowe, David J

2015-08-01

Three-dimensional (3D) changes in the midface following malar calcium hydroxyapatite (CaHa) injection have not been systematically analyzed. The authors analyzed 3D volume changes in midface and naso-labial fold (NLF) volume, as well as lateral movement in the NLF/naso-labial crease (NLC) junction following malar injection of CaHa in a cadaver model. A single surgeon injected CaHa in the supraperiosteal plane. Sequential images were obtained with the VECTRA 3D system pre- and post-1.5- and 3-cc CaHa injections. All measurements were performed by a single examiner. Injection location was verified anatomically. Injections were performed in 16 fresh cadaver hemi-faces. Maximal increases in projection were centered on the malar injection site, with associated decreases in projection and volume in the infero-medial locations. Relative mean increases in volume of 3.16 cc and 4.94 cc were observed following the 1.5-cc and 3-cc injections, respectively. There was a relative decrease in the volume of the NLF of -0.3 cc and -0.4 cc following the 1.5- and 3-cc injections, respectively. Injection of CaHa was associated with lateral movements of the NLF-NLC junction at the level of the nasal sill, philtral columns, and oral commissure, measuring 2.7, 2.5, and 1.9 mm and 2.8, 2.9, and 2.4 mm following the 1.5- and 3-cc injections, respectively. Anatomical dissection verified the location in the supraperiosteal space and within the middle malar fat pad. Following malar CaHa injection, 3D photographic analysis showed a measureable lifting effect with recruitment of ptotic tissue and lateral movement of the NLF-NLC junction in a cadaver model. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Initiation and Activation of Faults in Dry and Wet Rock by Fluid Injection

NASA Astrophysics Data System (ADS)

Stanchits, S.; Mayr, S.; Shapiro, S. A.; Dresen, G.

2008-12-01

We studied fracturing of rock samples induced by water injection in axial compression tests on cylindrical specimens of Flechtingen sandstone and Aue granite of 50 mm diameter and 105-125 mm length. Samples were intact solid rock cylinders and cylinders with central boreholes of 5 mm diameter and 52 mm length or through-boreholes of 2.5 mm diameter. To monitor acoustic emissions (AE) and ultrasonic velocities, twelve P-wave and six polarized S-wave sensors were glued to the cylindrical surface of the rock. Full waveforms were stored in a 12 channel transient recording system (PROEKEL, Germany). Polarity of AE first motion was used to discriminate source types associated with tensile, shear and pore-collapse cracking. To monitor strain, two pairs of orthogonally oriented strain-gages were glued onto the specimen surface. Samples were deformed in two consecutive loading steps: 1) Initial triaxial loading was performed at 20-50 MPa confining pressure on dry (under vacuum) or fully saturated samples until the yield point was reached. 2) In a second stage distilled water was injected into the samples with pore pressure increasing up to 20 MPa. For saturated samples the pore pressure was increased in steps and in periodic pulses. Injection of water into dry porous sandstone resulted in propagation of an AE hypocenter cloud closely linked to propagation of the water front. Position of the migrating water front was estimated from ultrasonic velocity measurements and measurements of the injected water volume. Propagation rate of AE-induced cloud parallel to bedding was higher than perpendicular to bedding, possibly related to permeability anisotropy. Nucleation of a brittle shear fault occurred at a critical pore pressure level with a nucleation patch located at the central borehole. Micro-structural analysis of fractured samples shows excellent agreement between location of AE hypocenters and macroscopic faults.

Single-sample method for the estimation of glomerular filtration rate in children

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tauxe, W.N.; Bagchi, A.; Tepe, P.G.

1987-03-01

A method for the determination of the glomerular filtration rate (GFR) in children which involves the use of a single-plasma sample (SPS) after the injection of a radioactive indicator such as radioiodine labeled diatrizoate (Hypaque) has been developed. This is analogous to previously published SPS techniques of effective renal plasma flow (ERPF) in adults and children and GFR SPS techniques in adults. As a reference standard, GFR has been calculated from compartment analysis of injected radiopharmaceuticals (Sapirstein Method). Theoretical volumes of distribution were calculated at various times after injection (Vt) by dividing the total injected counts (I) by the plasmamore » concentration (Ct) expressed in liters, determined by counting an aliquot of plasma in a well type scintillation counter. Errors of predicting GFR from the various Vt values were determined as the standard error of estimate (Sy.x) in ml/min. They were found to be relatively high early after injection and to fall to a nadir of 3.9 ml/min at 91 min. The Sy.x Vt relationship was examined in linear, quadratic, and exponential form, but the simpler linear relationship was found to yield the lowest error. Other data calculated from the compartment analysis of the reference plasma disappearance curves are presented, but at this time have apparently little clinical relevance.« less

An accessible micro-capillary electrophoresis device using surface-tension-driven flow

PubMed Central

Mohanty, Swomitra K.; Warrick, Jay; Gorski, Jack; Beebe, David J.

2010-01-01

We present a rapidly fabricated micro-capillary electrophoresis chip that utilizes surface-tension-driven flow for sample injection and extraction of DNA. Surface-tension-driven flow (i.e. passive pumping) injects a fixed volume of sample that can be predicted mathematically. Passive pumping eliminates the need for tubing, valves, syringe pumps, and other equipment typically needed for interfacing with microelectrophoresis chips. This method requires a standard micropipette to load samples before separation, and remove the resulting bands after analysis. The device was made using liquid phase photopolymerization to rapidly fabricate the chip without the need of special equipment typically associated with the construction of microelectrophoresis chips (e.g. cleanroom). Batch fabrication time for the device presented here was 1.5 h including channel coating time to suppress electroosmotic flow. Devices were constructed out of poly-isobornyl acrylate and glass. A standard microscope with a UV source was used for sample detection. Separations were demonstrated using Promega BenchTop 100 bp ladder in hydroxyl ethyl cellulose (HEC) and oligonucleotides of 91 and 118 bp were used to characterize sample injection and extraction of DNA bands. The end result was an inexpensive micro-capillary electrophoresis device that uses tools (e.g. micropipette, electrophoretic power supplies, and microscopes) already present in most labs for sample manipulation and detection, making it more accessible for potential end users. PMID:19425002

Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia.

PubMed

Lung, Solveig; Luksch, Alexandra; Weigert, Günther; Georgopoulos, Michael; Menapace, Rupert; Polska, Elzbieta; Garhofer, Gerhard; Findl, Oliver; Schmetterer, Leopold

2006-09-01

To test the hypothesis that ocular blood-flow response to peribulbar anesthesia can be reduced by using a smaller volume of anesthetic mixture. Departments of Ophthalmology and Clinical Pharmacology, Medical University of Vienna, Vienna, Austria. Twenty patients scheduled for bilateral age-related cataract surgery were enrolled in a prospective randomized balanced observer-masked crossover study. Two study days with a 2 mL injection volume or 5 mL injection volume used for peribulbar anesthesia were scheduled. On 1 study day, patients received the 1-dose regimen and on the other study day, when the contralateral eye had surgery, patients received the other injection volume. On both study days, the anesthetic mixture consisted of an equal amount of lidocaine, bupivacaine, and hyaluronidase independently of the injection volume. Intraocular pressure (IOP), blood pressure, and pulse rate were measured noninvasively. Ocular fundus pulsation amplitude (FPA) and peak systolic and end diastolic flow velocities in the central retinal artery were measured with laser interferometry and color Doppler imaging, respectively. The results were recorded as means +/- SD. Peribulbar anesthesia increased IOP and reduced FPA and flow velocities in the central retinal artery. The effects on IOP (5 mL, 35.1% +/- 16.0%; 2 mL, 14.1% +/- 14.1%; P<.001) and ocular hemodynamic parameters (FPA: 5 mL, -17.5% +/- 7.8%/2 mL, -7.3% +/- 7.2%, P<.001; peak systolic velocity: 5 mL, -19.5% +/- 10.7%/2 mL, -10.6% +/- 9.8%, P = .013; end diastolic velocity: 5 mL, -16.7% +/- 6.2%/2 mL, -8.4% +/- 7.3%, P = .005) were more pronounced with the 5 mL injection volume than with the 2 mL injection volume. An injection volume of 2 mL instead of 5 mL reduced the ocular blood-flow response to peribulbar anesthesia. This procedure may be used in patients with ocular vascular disease to reduce the incidence of anesthesia-induced ischemia and loss of vision.

Environmental assessment of NH/sub 3/ injection for an industrial package boiler. Volume 1. Technical results. Final report, January 1983-January 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castaldini, C.; DeRosier, R.; Waterland, L.R.

1986-02-01

The report discusses emission results from comprehensive flue gas sampling of a gas- and oil-fired industrial boiler equipped with Exxon's Thermal DeNO/sub x/ Ammonia Injection Process for NO/sub x/ reduction. Comprehensive emission measurements included continuous monitoring of flue gas emissions; source assessment sampling system (SASS) tests; EPA Method 5/17 for solid and condensible particulate emissions and ammonia emissions; controlled condensation system for SO/sub 2/ and SO/sub 3/; and N/sub 2/O emission sampling. Ammonia injection at a NH/sub 3//NO molar ratio of 2.52 gave a NO/sub x/ reduction of 41% from an uncontrolled level of 234 ppm to a controlled levelmore » of 137 ppm. NH/sub 3/ emissions increased from 11 ppm for the baseline to an average of 430 ppm for ammonia injection. Nitrous oxide, N/sub 2/O was reduced 68% from a 50 ppm baseline level to a 17 ppm controlled level. Total particulate emissions increased by an order of magnitude from a baseline of 17.7 ng/J to a controlled level of 182 ng/J. The increase is in part attributed to formation of ammonia sulfate and bisulfate from residual ammonia and SO/sub x/. Total organic emissions were at a moderate level and showed a relative concentration in the nonvolatile category. Organic emissions of CO and trace inorganic elements were not significantly affected by ammonia injection.« less

Highly selective solid-phase extraction and large volume injection for the robust gas chromatography-mass spectrometric analysis of TCA and TBA in wines.

PubMed

Insa, S; Anticó, E; Ferreira, V

2005-09-30

A reliable solid-phase extraction (SPE) method for the simultaneous determination of 2,4,6-trichloroanisole (TCA) and 2,4,6-tribromoanisole (TBA) in wines has been developed. In the proposed procedure 50 mL of wine are extracted in a 1 mL cartridge filled with 50 mg of LiChrolut EN resins. Most wine volatiles are washed up with 12.5 mL of a water:methanol solution (70%, v/v) containing 1% of NaHCO3. Analytes are further eluted with 0.6 mL of dichloromethane. A 40 microL aliquot of this extract is directly injected into a PTV injector operated in the solvent split mode, and analysed by gas chromatography (GC)-ion trap mass spectrometry using the selected ion storage mode. The solid-phase extraction, including sample volume and rinsing and elution solvents, and the large volume GC injection have been carefully evaluated and optimized. The resulting method is precise (RSD (%) < 6% at 100 ng L(-1)), sensitive (LOD were 0.2 and 0.4 ng/L for TCA and TBA, respectively), robust (the absolute recoveries of both analytes are higher than 80% and consistent wine to wine) and friendly to the GC-MS system (the extract is clean, simple and free from non-volatiles).

Electrokinetic injection techniques in microfluidic chips.

PubMed

Fu, L M; Yang, R J; Lee, G B; Liu, H H

2002-10-01

The separation efficiency of a microfluidic chip is influenced to a significant degree by the flow field conditions within the injection microchannel. Therefore, an understanding of the physics of the flow within this channel is beneficial in the design and operation of such a system. The configuration of an injection system is determined by the volume of the sample plug that is to be delivered to the separation process. Accordingly, this paper addresses the design and testing of injection systems with a variety of configurations, including a simple cross, a double-T, and a triple-T configuration. This paper also presents the design of a unique multi-T injection configuration. Each injection system cycles through a predetermined series of steps, in which the electric field magnitude and distribution within the various channels is strictly manipulated, to effectuate a virtual valve. The uniquemulti-T configuration injection system presented within this paper has the ability to simulate the functions of the cross, double-T, and triple-T systems through appropriate manipulations of the electric field within its various channels. In other words, the proposed design successfully combines several conventional injection systems within a single microfluidic chip.

Sample preparation system for microfluidic applications

DOEpatents

Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA; Harnett, Cindy K [Livermore, CA

2007-05-08

An apparatus that couples automated injection with flow feedback to provide nanoliter accuracy in controlling microliter volumes. The apparatus comprises generally a source of hydraulic fluid pressure, a fluid isolator joined to the outlet of the hydraulic pressure source and a flow sensor to provide pressure-driven analyte metering. For operation generally and particularly in microfluidic systems the hydraulic pressure source is typically an electrokinetic (EK) pump that incorporates gasless electrodes. The apparatus is capable of metering sub-microliter volumes at flowrates of 1 100 .mu.L/min into microsystem load pressures of up to 1000 50 psi, respectively. Flowrates can be specified within 0.5 .mu.L/min and volumes as small as 80 nL can be metered.

nZVI injection into variably saturated soils: Field and modeling study.

PubMed

Chowdhury, Ahmed I A; Krol, Magdalena M; Kocur, Christopher M; Boparai, Hardiljeet K; Weber, Kela P; Sleep, Brent E; O'Carroll, Denis M

2015-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI field-scale mobility. In this study, a field test was combined with numerical modeling to examine nZVI reactivity along with transport properties in variably saturated soils. The field test consisted of 142L of carboxymethyle cellulose (CMC) stabilized monometallic nZVI synthesized onsite and injected into a variably saturated zone. Periodic groundwater samples were collected from the injection well, as well as, from two monitoring wells to analyze for chlorinated solvents and other geochemistry indicators. This study showed that CMC stabilized monometallic nZVI was able to decrease tricholorethene (TCE) concentrations in groundwater by more than 99% from the historical TCE concentrations. A three dimensional, three phase, finite difference numerical simulator, (CompSim) was used to further investigate nZVI and polymer transport at the variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the mass of nZVI delivered to the saturated and unsaturated zones and distinguished the nZVI phase (i.e. aqueous or attached). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity and viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher nZVI volume delivered more iron particles at a given distance; however, the travel distance was not proportional to the increase in volume. Moreover, simulation results showed that using a 1D transport equation to simulate nZVI migration in the subsurface may overestimate the travel distance. This is because the 1D transport equation assumes a constant velocity while pore water velocity radially decreases from the well during injection. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and that a numerical simulator can be a valuable tool for optimal design of nZVI field applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Fast automated dual-syringe based dispersive liquid-liquid microextraction coupled with gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in environmental water samples.

PubMed

Guo, Liang; Tan, Shufang; Li, Xiao; Lee, Hian Kee

2016-03-18

An automated procedure, combining low density solvent based solvent demulsification dispersive liquid-liquid microextraction (DLLME) with gas chromatography-mass spectrometry analysis, was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Capitalizing on a two-rail commercial autosampler, fast solvent transfer using a large volume syringe dedicated to the DLLME process, and convenient extract collection using a small volume microsyringe for better GC performance were enabled. Extraction parameters including the type and volume of extraction solvent, the type and volume of dispersive solvent and demulsification solvent, extraction and demulsification time, and the speed of solvent injection were investigated and optimized. Under the optimized conditions, the linearity ranged from 0.1 to 50 μg/L, 0.2 to 50 μg/L, and 0.5 to 50 μg/L, depending on the analytes. Limits of detection were determined to be between 0.023 and 0.058 μg/L. The method was applied to determine PAHs in environmental water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of the Reservoir Volume on the Discharge Pressures in the Injection System of the N.A.C.A. Spray Photography Equipment

NASA Technical Reports Server (NTRS)

Rothrock, A M; Lee, D W

1932-01-01

Tests were made to determine the effect of the reservoir volume on the discharge pressures in the injection system of the N.A.C.A. spray photography equipment. The data obtained are applicable to the design of a common rail fuel-injection system. The data show that an injection system of the type described can be designed so that not more than full load fuel quantity can be injected into the engine cylinders, and so that the fuel spray characteristics remain constant over a large range of engine speeds. Formulas are presented for computing the volume of the reservoir and the diameter of the discharge orifice.

Determination of low molecular weight alcohols including fusel oil in various samples by diethyl ether extraction and capillary gas chromatography.

PubMed

Woo, Kang-Lyung

2005-01-01

Low molecular weight alcohols including fusel oil were determined using diethyl ether extraction and capillary gas chromatography. Twelve kinds of alcohols were successfully resolved on the HP-FFAP (polyethylene glycol) capillary column. The diethyl ether extraction method was very useful for the analysis of alcohols in alcoholic beverages and biological samples with excellent cleanliness of the resulting chromatograms and high sensitivity compared to the direct injection method. Calibration graphs for all standard alcohols showed good linearity in the concentration range used, 0.001-2% (w/v) for all alcohols. Salting out effects were significant (p < 0.01) for the low molecular weight alcohols methanol, isopropanol, propanol, 2-butanol, n-butanol and ethanol, but not for the relatively high molecular weight alcohols amyl alcohol, isoamyl alcohol, and heptanol. The coefficients of variation of the relative molar responses were less than 5% for all of the alcohols. The limits of detection and quantitation were 1-5 and 10-60 microg/L for the diethyl ether extraction method, and 10-50 and 100-350 microg/L for the direct injection method, respectively. The retention times and relative retention times of standard alcohols were significantly shifted in the direct injection method when the injection volumes were changed, even with the same analysis conditions, but they were not influenced in the diethyl ether extraction method. The recoveries by the diethyl ether extraction method were greater than 95% for all samples and greater than 97% for biological samples.

Hydraulic fracturing volume is associated with induced earthquake productivity in the Duvernay play

NASA Astrophysics Data System (ADS)

Schultz, R.; Atkinson, G.; Eaton, D. W.; Gu, Y. J.; Kao, H.

2018-01-01

A sharp increase in the frequency of earthquakes near Fox Creek, Alberta, began in December 2013 in response to hydraulic fracturing. Using a hydraulic fracturing database, we explore relationships between injection parameters and seismicity response. We show that induced earthquakes are associated with completions that used larger injection volumes (104 to 105 cubic meters) and that seismic productivity scales linearly with injection volume. Injection pressure and rate have an insignificant association with seismic response. Further findings suggest that geological factors play a prominent role in seismic productivity, as evidenced by spatial correlations. Together, volume and geological factors account for ~96% of the variability in the induced earthquake rate near Fox Creek. This result is quantified by a seismogenic index–modified frequency-magnitude distribution, providing a framework to forecast induced seismicity.

Miniaturizing and automation of free acidity measurements for uranium (VI)-HNO3 solutions: Development of a new sequential injection analysis for a sustainable radio-analytical chemistry.

PubMed

Néri-Quiroz, José; Canto, Fabrice; Guillerme, Laurent; Couston, Laurent; Magnaldo, Alastair; Dugas, Vincent

2016-10-01

A miniaturized and automated approach for the determination of free acidity in solutions containing uranium (VI) is presented. The measurement technique is based on the concept of sequential injection analysis with on-line spectroscopic detection. The proposed methodology relies on the complexation and alkalimetric titration of nitric acid using a pH 5.6 sodium oxalate solution. The titration process is followed by UV/VIS detection at 650nm thanks to addition of Congo red as universal pH indicator. Mixing sequence as well as method validity was investigated by numerical simulation. This new analytical design allows fast (2.3min), reliable and accurate free acidity determination of low volume samples (10µL) containing uranium/[H(+)] moles ratio of 1:3 with relative standard deviation of <7.0% (n=11). The linearity range of the free nitric acid measurement is excellent up to 2.77molL(-1) with a correlation coefficient (R(2)) of 0.995. The method is specific, presence of actinide ions up to 0.54molL(-1) does not interfere on the determination of free nitric acid. In addition to automation, the developed sequential injection analysis method greatly improves the standard off-line oxalate complexation and alkalimetric titration method by reducing thousand fold the required sample volume, forty times the nuclear waste per analysis as well as the analysis time by eight fold. These analytical parameters are important especially in nuclear-related applications to improve laboratory safety, personnel exposure to radioactive samples and to drastically reduce environmental impacts or analytical radioactive waste. Copyright © 2016 Elsevier B.V. All rights reserved.

Relationship between trabecular texture features of CT images and an amount of bone cement volume injection in percutaneous vertebroplasty

NASA Astrophysics Data System (ADS)

Tack, Gye Rae; Choi, Hyung Guen; Shin, Kyu-Chul; Lee, Sung J.

2001-06-01

Percutaneous vertebroplasty is a surgical procedure that was introduced for the treatment of compression fracture of the vertebrae. This procedure includes puncturing vertebrae and filling with polymethylmethacrylate (PMMA). Recent studies have shown that the procedure could provide structural reinforcement for the osteoporotic vertebrae while being minimally invasive and safe with immediate pain relief. However, treatment failures due to disproportionate PMMA volume injection have been reported as one of complications in vertebroplasty. It is believed that control of PMMA volume is one of the most critical factors that can reduce the incidence of complications. In this study, appropriate amount of PMMA volume was assessed based on the imaging data of a given patient under the following hypotheses: (1) a relationship can be drawn between the volume of PMMA injection and textural features of the trabecular bone in preoperative CT images and (2) the volume of PMMA injection can be estimated based on 3D reconstruction of postoperative CT images. Gray-level run length analysis was used to determine the textural features of the trabecular bone. The width of trabecular (T-texture) and the width of intertrabecular spaces (I-texture) were calculated. The correlation between PMMA volume and textural features of patient's CT images was also examined to evaluate the appropriate PMMA amount. Results indicated that there was a strong correlation between the actual PMMA injection volume and the area of the intertrabecular space and that of trabecular bone calculated from the CT image (correlation coefficient, requals0.96 and requals-0.95, respectively). T- texture (requals-0.93) did correlate better with the actual PMMA volume more than the I-texture (requals0.57). Therefore, it was demonstrated that appropriate PMMA injection volume could be predicted based on the textural analysis for better clinical management of the osteoporotic spine.

Population pharmacokinetics of enrofloxacin in purple sea stars (Pisaster ochraceus) following an intracoelomic injection or extended immersion.

PubMed

Rosenberg, Justin F; Haulena, Martin; Phillips, Brianne E; Harms, Craig A; Lewbart, Gregory A; Lahner, Lesanna L; Papich, Mark G

2016-11-01

OBJECTIVE To determine population pharmacokinetics of enrofloxacin in purple sea stars (Pisaster ochraceus) administered an intracoelomic injection of enrofloxacin (5 mg/kg) or immersed in an enrofloxacin solution (5 mg/L) for 6 hours. ANIMALS 28 sea stars of undetermined age and sex. PROCEDURES The study had 2 phases. Twelve sea stars received an intracoelomic injection of enrofloxacin (5 mg/kg) or were immersed in an enrofloxacin solution (5 mg/L) for 6 hours during the injection and immersion phases, respectively. Two untreated sea stars were housed with the treated animals following enrofloxacin administration during both phases. Water vascular system fluid samples were collected from 4 sea stars and all controls at predetermined times during and after enrofloxacin administration. The enrofloxacin concentration in those samples was determined by high-performance liquid chromatography. For each phase, noncompartmental analysis of naïve averaged pooled samples was used to obtain initial parameter estimates; then, population pharmacokinetic analysis was performed that accounted for the sparse sampling technique used. RESULTS Injection phase data were best fit with a 2-compartment model; elimination half-life, peak concentration, area under the curve, and volume of distribution were 42.8 hours, 18.9 μg/mL, 353.8 μg•h/mL, and 0.25 L/kg, respectively. Immersion phase data were best fit with a 1-compartment model; elimination half-life, peak concentration, and area under the curve were 56 hours, 36.3 μg•h/mL, and 0.39 μg/mL, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the described enrofloxacin administration resulted in water vascular system fluid drug concentrations expected to exceed the minimum inhibitory concentration for many bacterial pathogens.

Adaptive engine injection for emissions reduction

DOEpatents

Reitz, Rolf D. : Sun, Yong

2008-12-16

NOx and soot emissions from internal combustion engines, and in particular compression ignition (diesel) engines, are reduced by varying fuel injection timing, fuel injection pressure, and injected fuel volume between low and greater engine loads. At low loads, fuel is injected during one or more low-pressure injections occurring at low injection pressures between the start of the intake stroke and approximately 40 degrees before top dead center during the compression stroke. At higher loads, similar injections are used early in each combustion cycle, in addition to later injections which preferably occur between about 90 degrees before top dead center during the compression stroke, and about 90 degrees after top dead center during the expansion stroke (and which most preferably begin at or closely adjacent the end of the compression stroke). These later injections have higher injection pressure, and also lower injected fuel volume, than the earlier injections.

A dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry for the determination of nine bisphenols in bottled carbonated beverages.

PubMed

Mandrah, Kapil; Satyanarayana, G N V; Roy, Somendu Kumar

2017-12-15

In the present study, a method has been efficiently developed for the first time to determine nine bisphenol analogues [bisphenol A (BPA), bisphenol C (BPC), bisphenol AF (BPAF), bisphenol E (BPE), bisphenol F (BPF), bisphenol G (BPG), bisphenol M (BPM), bisphenol S (BPS), and bisphenol Z (BPZ)] together in bottled carbonated beverages (collected from the local market of Lucknow, India) using dispersive liquid-liquid microextraction process. This is based on solidification of floating organic droplet (DLLME-SFO) followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry. The process investigated parameters of DLLME-SFO (including the type of extraction and disperser solvents with their volumes, effect of pH, ionic strength, and the sample volume), factors influencing to injection port derivatization like, collision energy, injector port temperature, derivatizing reagent with sample injection volume, and type of organic solvent. BPA, BPF, BPZ, and BPS were detected in each sample; whereas, other bisphenols were also detected in some carbonated beverage samples. After optimizing the required conditions, good linearity of analytes was achieved in the range of 0.097-100ngmL -1 with coefficients of determination (R 2 )≥0.995. Intra-day and inter day precision of the method was good, with relative standard deviation (% RSD)≤10.95%. The limits of detection (LOD) and limits of quantification (LOQ) values of all bisphenols were ranged from 0.021 to 0.104ngmL -1 and 0.070 to 0.343ngmL -1 , respectively. The recovery of extraction was good (73.15-95.08%) in carbonated beverage samples and good enrichment factors (96.36-117.33) were found. Thus, the developed method of microextraction was highly precise, fast, and reproducible to determine the level of contaminants in bottled carbonated beverages. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental assessment of a crude-oil heater using staged air lances for NOx reduction. Volume 1. Technical results. Final report June 1981-November 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeRosier, R.

1984-07-01

This volume of the report gives emission results from field tests of a crude-oil process heater burning a combination of oil and refinery gas. The heater had been modified by adding a system for injecting secondary air to reduce NOx emissions. One test was conducted with the staged air system (low NOx), and the other, without (baseline). Tests included continuous monitoring of flue gas emissions and source assessment sampling system (SASS) sampling of the flue gas with subsequent laboratory analysis of the samples utilizing gas chromatography (GC), infrared spectrometry (IR), gas chromatography/mass spectroscopy (GC/MS), and low resolution mass spectrometry (SSMS)more » for trace metals. LRMS analysis suggested the presence of eight compound categories in the organic emissions during the baseline test and four in the low-NOx test.« less

Method to make accurate concentration and isotopic measurements for small gas samples

NASA Astrophysics Data System (ADS)

Palmer, M. R.; Wahl, E.; Cunningham, K. L.

2013-12-01

Carbon isotopic ratio measurements of CO2 and CH4 provide valuable insight into carbon cycle processes. However, many of these studies, like soil gas, soil flux, and water head space experiments, provide very small gas sample volumes, too small for direct measurement by current constant-flow Cavity Ring-Down (CRDS) isotopic analyzers. Previously, we addressed this issue by developing a sample introduction module which enabled the isotopic ratio measurement of 40ml samples or smaller. However, the system, called the Small Sample Isotope Module (SSIM), does dilute the sample during the delivery with inert carrier gas which causes a ~5% reduction in concentration. The isotopic ratio measurements are not affected by this small dilution, but researchers are naturally interested accurate concentration measurements. We present the accuracy and precision of a new method of using this delivery module which we call 'double injection.' Two portions of the 40ml of the sample (20ml each) are introduced to the analyzer, the first injection of which flushes out the diluting gas and the second injection is measured. The accuracy of this new method is demonstrated by comparing the concentration and isotopic ratio measurements for a gas sampled directly and that same gas measured through the SSIM. The data show that the CO2 concentration measurements were the same within instrument precision. The isotopic ratio precision (1σ) of repeated measurements was 0.16 permil for CO2 and 1.15 permil for CH4 at ambient concentrations. This new method provides a significant enhancement in the information provided by small samples.

A Fast, Accurate and Sensitive GC-FID Method for the Analyses of Glycols in Water and Urine

NASA Technical Reports Server (NTRS)

Kuo, C. Mike; Alverson, James T.; Gazda, Daniel B.

2017-01-01

Glycols, specifically ethylene glycol and 1,2-propanediol, are some of the major organic compounds found in the humidity condensate samples collected on the International Space Station. The current analytical method for glycols is a GC/MS method with direct sample injection. This method is simple and fast, but it is not very sensitive. Reporting limits for ethylene glycol and 1,2-propanediol are only 1 ppm. A much more sensitive GC/FID method was developed, in which glycols were derivatized with benzoyl chloride for 10 minutes before being extracted with hexane. Using 1,3-propanediol as an internal standard, the detection limits for the GC/FID method was determined to be 50 ppb and the analysis only takes 7 minutes. Data from the GC/MS and the new GC/FID methods shows excellent agreement with each other. Factors affecting the sensitivity, including sample volume, NaOH concentration and volume, volume of benzoyl chloride, reaction time and temperature, were investigated. Interferences during derivatization and possible method to reduce interferences were also investigated.

Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

PubMed

Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

2014-03-01

Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate. Copyright © 2014 Elsevier B.V. All rights reserved.

40 CFR 146.69 - Reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pursuant to § 146.67(f) and the response taken; (4) The total volume of fluid injected; (5) Any change in the annular fluid volume; (6) The physical, chemical and other relevant characteristics of injected...

Optimization of large-volume injection for the determination of polychlorinated biphenyls in children's fast-food menus by low-resolution mass spectrometry.

PubMed

Esteve-Turrillas, Francesc A; Caupos, Emilie; Llorca, Isabel; Pastor, Agustín; de la Guardia, Miguel

2008-03-26

This study includes the determination of five indicator polychlorinated biphenyls (PCBs) (52, 101, 153, 138, and 180), six non-ortho PCBs (35, 80, 81, 77, 126, and 169), and two mono-ortho PCBs (28 and 118) in fast food for children. A freeze-dried sample of 10 g is extracted by using pressurized n-hexane in two 5 min cycles at 120 degrees C and 100 mbar. Fatty extracts were cleaned up by means of acetonitrile/n-hexane partitioning and gel-permeation chromatography. The fractionation of non-ortho, mono-ortho, and indicator PCBs was made on graphitized carbon solid-phase extraction cartridges by using n-hexane, n-hexane/toluene (99:1, v/v), and toluene as elution solvents. Gas chromatography coupled to tandem mass spectrometry and large-volume injections with a programmed-temperature vaporizer (PTV-LV) were used to increase sensitivity and selectivity of the PCB determination. The PTV-LV injection settings, that is, vaporizing temperature, vaporizing time, and purge flow, were optimized by using a central composite design. A 15-40 times increased sensitivity was reached as compared with that obtained with the conventional 1 microL splitless injection. The limits of detection achieved were between 0.3 and 1.2 pg/g, and repeatability data, as relative standard deviation varied, ranged from 2 to 9% for the 0.05 ng/mL PCB level.

[Detection of rifampicin concentration in cerebrospinal fluid by online enrichment and restricted-access media coupled with high-performance liquid chromatography].

PubMed

Yang, Xiaoping; Zhang, Xiaohui; Huang, Yanping; Wang, Rong; Xia, Hua; Li, Wenbin; Guo, YouMin

2015-11-01

To establish a method for detecting rifampicin in human cerebrospinal fluid (CSF) with restricted access media coupled with high-performance liquid chromatography that allows online direct sample injection and enrichment. We used the column of restricted access media as the pre-treatment column and a C18 column as the analytical column. The mobile phase of pre-treatment column was water-methanol (95:5,V/V) and the flow rate was 1 mL/min; the mobile phase of the analytical column was methanol-acetonitrile-10 mmol/L ammonuium acetate (volume ratio of 60:5:35). The detection wavelength was 254 nm and the column temperature was set at 25 degrees celsius;. For an injection volume of 100 µL, the peak area of rifampicin was 5.33 times that for an injection volume of 20 µL, and the limit of detection was effectively improved. The calibration curve showed an excellent linear relationship (r=0.9997) between rifampicin concentrations and peak areas within the concentration range of 0.25 to 8 µg/mL in CSF. The limits of detection and quantification was 0.07 µg/mL and 0.25 µg/mL, respecetively, with intra-day and inter-day assay precisions and relative standard deviation (RSD%) all below 5%. The recoveries of rifampicin at 3 blank spiked levels (low, medium, and high) ranged from 87.69% to 102.11%. In patients taking oral rifampicin at the dose of 10 mg/kg, the average rifampicin concentration was 0.29 in the CSF at 2 h after medication. The method we established is simple and fast for detecting rifampicin in CSF and allows direct online injection and enrichment with good detection precisions and accuracies.

Novel evidence that nitric oxide of the medial septal area influences the salivary secretion induced by pilocarpine.

PubMed

Saad, Wilson Abrão; Guarda, Ismael Francisco Motta Siqueira; Camargo, Luiz Antonio de Arruda; dos Santos, Talmir Augusto Faria Brisola; Saad, William Abrão; Simões, Sylvio; Guarda, Renata Saad

2002-04-05

Our studies have focused on the effect of injection of L-NAME and sodium nitroprussiate (SNP) on the salivary secretion, arterial blood pressure, sodium excretion and urinary volume induced by pilocarpine which was injected into the medial septal area (MSA). Rats were anesthetized with urethane (1.25 g/kg b. wt.) and a stainless steel cannula was implanted into their MSA. The amount of saliva secretion was studied over a five-minute period after injection of pilocarpine into MSA. Injection of pilocarpine (10, 20, 40, 80, 160 microg/microl) into MSA produced a dose-dependent increase in salivary secretion. L-NG-nitro arginine methyl-esther (L-NAME) (40 microg/microl), a nitric oxide (NO) synthase inhibitor, was injected into MSA prior to the injection of pilocarpine into MSA, producing an increase in salivary secretion due to the effect of pilocarpine. Sodium nitroprussiate (SNP) (30 microg/microl) was injected into MSA prior to the injection of pilocarpine into MSA attenuating the increase in salivary secretion induced by pilocarpine. Medial arterial pressure (MAP) increase after injections of pilocarpine into the MSA. L-NAME injected into the MSA prior to injection of pilocarpine into MSA increased the MAP. SNP injected into the MSA prior to pilocarpine attenuated the effect of pilocarpine on MAP. Pilocarpine (40 ug/ul) injected into the MAS induced an increase in sodium and urinary excretion. L-NAME injected prior to pilocarpine into the MSA increased the urinary sodium excretion and urinary volume induced by pilocarpine. SNP injected prior to pilocarpine into the MSA decreased the sodium excretion and urinary volume induced by pilocarpine. All these roles of pilocarpine depend on the release of nitric oxide into the MSA. We may also conclude that the MSA is involved with the cholinergic excitatory mechanism that induce salivary secretion, increase in MAP and increase in sodium excretion and urinary volume.

A simple device to convert a small-animal PET scanner into a multi-sample tissue and injection syringe counter.

PubMed

Green, Michael V; Seidel, Jurgen; Choyke, Peter L; Jagoda, Elaine M

2017-10-01

We describe a simple fixture that can be added to the imaging bed of a small-animal PET scanner that allows for automated counting of multiple organ or tissue samples from mouse-sized animals and counting of injection syringes prior to administration of the radiotracer. The combination of imaging and counting capabilities in the same machine offers advantages in certain experimental settings. A polyethylene block of plastic, sculpted to mate with the animal imaging bed of a small-animal PET scanner, is machined to receive twelve 5-ml containers, each capable of holding an entire organ from a mouse-sized animal. In addition, a triangular cross-section slot is machined down the centerline of the block to secure injection syringes from 1-ml to 3-ml in size. The sample holder is scanned in PET whole-body mode to image all samples or in one bed position to image a filled injection syringe. Total radioactivity in each sample or syringe is determined from the reconstructed images of these objects using volume re-projection of the coronal images and a single region-of-interest for each. We tested the accuracy of this method by comparing PET estimates of sample and syringe activity with well counter and dose calibrator estimates of these same activities. PET and well counting of the same samples gave near identical results (in MBq, R 2 =0.99, slope=0.99, intercept=0.00-MBq). PET syringe and dose calibrator measurements of syringe activity in MBq were also similar (R 2 =0.99, slope=0.99, intercept=- 0.22-MBq). A small-animal PET scanner can be easily converted into a multi-sample and syringe counting device by the addition of a sample block constructed for that purpose. This capability, combined with live animal imaging, can improve efficiency and flexibility in certain experimental settings. Copyright © 2017 Elsevier Inc. All rights reserved.

A hydrophobic ionic liquid compartmentalized sampling/labeling and its separation techniques in polydimethylsiloxane microchip capillary electrophoresis.

PubMed

Quan, Hong Hua; Li, Ming; Huang, Yan; Hahn, Jong Hoon

2017-01-01

This paper demonstrates a novel compartmentalized sampling/labeling method and its separation techniques using a hydrophobic ionic liquid (IL)-1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imidate (BmimNTf 2 )-as the immiscible phase, which is capable of minimizing signal losses during microchip capillary electrophoresis (MCE). The MCE device consists of a silica tube connected to a straight polydimethylsiloxane (PDMS) separation channel. Poly(diallyldimethylammonium chloride) (PDDAC) was coated on the inner surface of channel to ease the introduction of IL plugs and enhance the IL wetting on the PDMS surface for sample releasing. Electroosmotic flow (EOF)-based sample compartmentalization was carried out through a sequenced injection into sampling tubes with the following order: leading IL plug/sample segment/terminal IL plug. The movement of the sample segment was easily controlled by applying an electrical voltage across both ends of the chip without a sample volume change. This approach effectively prevented analyte diffusion before injection into MCE channels. When the sample segment was manipulated to the PDDAC-modified PDMS channel, the sample plug then was released from isolation under EOF while IL plugs adsorbed onto channel surfaces owing to strong adhesion. A mixture of flavin adenine nucleotides (FAD) and flavin mononucleotides (FMN) was successfully separated on a 2.5 cm long separation channel, for which the theoretical numbers of plates were 15 000 and 17 000, respectively. The obtained peak intensity was increased 6.3-fold over the corresponding value from conventional electrokinetic injection with the same sampling time. Furthermore, based on the compartmented sample segment serving as an interim reactor, an on-chip fluorescence labeling is demonstrated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Injectable self inflating hydrogel pellet expanders for the treatment of orbital volume deficiency in congenital microphthalmos: preliminary results with a new therapeutic approach

PubMed Central

Schittkowski, M P; Guthoff, R F

2006-01-01

Background/aim Children with congenital microphthalmos are usually able to wear an eye prosthesis but the cosmetic aspect is determined by the size of the orbital volume deficiency. Instead of using a ball shaped standard hydrogel expander or a regular orbital implant, which would necessitate enucleation of the microphthalmic eye, this study investigates the feasibility of volume augmentation with injectable pellet expanders, as formerly suggested for acquired anophthalmos in adults only. Method The pellet expander is made from a self inflating hydrogel that takes up water by osmosis (dry state: length 8 mm, diameter 2 mm, volume 0.025 ml; in vitro hydrated state after around 1 day: length 15 mm, diameter 4 mm, volume 0.24 ml; swelling capacity: 9.6‐fold). This report concerns six patients (two girls and four boys) aged between 4 months and 42 months with unilateral microphthalmos who were treated by injection of 4–14 pellet expanders into the retrobulbar orbital tissue. Volume augmentation was 1–3.5 ml. The pellets were injected using a customised trocar and placed behind the microphthalmos directed into the intraconal space. Results The increasing orbital volume was noticeable within 2 days and was confirmed by ultrasonography and magnetic resonance imaging. The final result can be anticipated by the volume augmentation effect produced by the amount of saline solution injected in the orbital apex region. All patients were fitted with an artificial eye, which was subsequently enlarged every 3–5 months. Anophthalmic enophthalmos was fully compensated with this technique. No complications have been encountered to date. Conclusions Orbital volume augmentation with injectable self inflating hydrogel expander pellets is apparently a safe, quick, and minimally invasive technique for various indications in orbital reconstructive surgery—for example, to treat an enophthalmic appearance in microphthalmos and congenital or acquired anophthalmos. PMID:16707526

Liposuction: Anaesthesia challenges

PubMed Central

Sood, Jayashree; Jayaraman, Lakshmi; Sethi, Nitin

2011-01-01

Liposuction is one of the most popular treatment modalities in aesthetic surgery with certain unique anaesthetic considerations. Liposuction is often performed as an office procedure. There are four main types of liposuction techniques based on the volume of infiltration or wetting solution injected, viz dry, wet, superwet, and tumescent technique. The tumescent technique is one of the most common liposuction techniques in which large volumes of dilute local anaesthetic (wetting solution) are injected into the fat to facilitate anaesthesia and decrease blood loss. The amount of lignocaine injected may be very large, approximately 35-55 mg/kg, raising concerns regarding local anaesthetic toxicity. Liposuction can be of two types according to the volume of solution aspirated: High volume (>4,000 ml aspirated) or low volume (<4,000 ml aspirated). While small volume liposuction may be done under local/monitored anaesthesia care, large-volume liposuction requires general anaesthesia. As a large volume of wetting solution is injected into the subcutaneous tissue, the intraoperative fluid management has to be carefully titrated along with haemodynamic monitoring and temperature control. Assessment of blood loss is difficult, as it is mixed with the aspirated fat. Since most obese patients opt for liposuction as a quick method to lose weight, all concerns related to obesity need to be addressed in a preoperative evaluation. PMID:21808392

Analytical Chemistry in Microenvironments: Single Nerve Cells.

DTIC Science & Technology

1992-03-16

length of the capillary (34). Electroosmotic flow offers three key advantages for separation of small biological samples. First, this flow, if not...from microenvironments (ie. single cells). Indeed, volumes as low as 270 femtoliters have been injected using electroosmotic flow (15). Finally... electroosmotic flow provides a flat flow profile, since there is no stationary support between the origin of flow (capillary wall) and the bulk of solution

Techniques for immobilizing and bleeding marmots and woodrats.

PubMed

Frase, B A; Van Vuren, D

1989-07-01

Blood samples were obtained in the field by femoral vein puncture in bushy-tailed woodrats (Neotoma cinerea) and yellow-bellied marmots (Marmota flaviventris) that had been injected intramuscularly with ketamine hydrochloride. Dosages ranged from 50 mg/kg for marmots to 30 to 110 mg/kg for woodrats. Sedated animals were handled easily, and a volume of blood sufficient for hematological assays or electrophoresis could be collected.

A Combined Hazard Index Fire Test Methodology for Aircraft Cabin Materials. Volume II.

DTIC Science & Technology

1982-04-01

Technical Center. The report was divided into two parts: Part I described the improved technology investigated to upgrade existin methods for testing...proper implementation of the computerized data acquisition and reduction programs will improve materials hazards measurement precision. Thus, other...the hold chamber before and after injection of a sample, will improve precision and repeatability of measurement. The listed data acquisition and

Automation of sample processing for ICP-MS determination of 90Sr radionuclide at ppq level for nuclear technology and environmental purposes.

PubMed

Kołacińska, Kamila; Chajduk, Ewelina; Dudek, Jakub; Samczyński, Zbigniew; Łokas, Edyta; Bojanowska-Czajka, Anna; Trojanowicz, Marek

2017-07-01

90 Sr is a widely determined radionuclide for environmental purposes, nuclear waste control, and can be also monitored in coolants in nuclear reactor plants. In the developed method, the ICP-MS detection was employed together with sample processing in sequential injection analysis (SIA) setup, equipped with a lab-on-valve with mechanized renewal of sorbent bed for solid-phase extraction. The optimized conditions of determination included preconcentration of 90 Sr on cation-exchange column and removal of different type of interferences using extraction Sr-resin. The limit of detection of the developed procedure depends essentially on the configuration of the employed ICP-MS spectrometer and on the available volume of the sample to be analyzed. For 1L initial sample volume, the method detection limit (MDL) value was evaluated as 2.9ppq (14.5BqL -1 ). The developed method was applied to analyze spiked river water samples, water reference materials, and also simulated and real samples of the nuclear reactor coolant. Copyright © 2016 Elsevier B.V. All rights reserved.

Histologic Evaluation of Micronized AlloDerm After Injection Laryngoplasty in a Rabbit Model.

PubMed

Oldenburg, Michael S; Janus, Jeff; Voss, Steve; San Marina, Serban; Chen, Tiffany; Garcia, Joaquin; Ekbom, Dale

2017-05-01

Micronized AlloDerm is a commonly used injectable material for injection laryngoplasty; however, the histologic response to laryngeal implantation and resorption rate over time have not been elucidated. This study aimed to evaluate the in vivo response of micronized AlloDerm over time after laryngeal implantation using a rabbit model. Animal model. The left recurrent laryngeal nerve was sectioned in five New Zealand White rabbits to create a vocal cord paralysis. Two weeks later, injection laryngoplasty was performed with 100 μL of micronized AlloDerm. Animals were sacrificed 4 (two rabbits) and 12 (three rabbits) weeks after injection. Histologic sections were stained and evaluated by a single pathologist. Volume estimates were made by assuming the implant took an ellipsoid shape using dimensions calculated from histologic slides. In all cases, histological analysis revealed a lymphocytic inflammatory response infiltrating the peripheral margins of injection. After 4 weeks, the volume of injected material remaining in two rabbits was 404 and 278 mm 3 (average 341 mm 3 ). After 12 weeks, the volume of injected material remaining in three rabbits was 0, 61, and 124 mm 3 (average 62 mm 3 ), an 82% difference in volume of material between animals sacrificed at 4 weeks versus 12 weeks. Injection laryngoplasty using micronized AlloDerm induces a lymphocytic inflammatory response after injection in a rabbit model. Though a significant amount of material remains after 4 weeks, by 12 weeks the majority has been reabsorbed. NA Laryngoscope, 127:E166-E169, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Comparison of the image-derived radioactivity and blood-sample radioactivity for estimating the clinical indicators of the efficacy of boron neutron capture therapy (BNCT): 4-borono-2-18F-fluoro-phenylalanine (FBPA) PET study.

PubMed

Isohashi, Kayako; Shimosegawa, Eku; Naka, Sadahiro; Kanai, Yasukazu; Horitsugi, Genki; Mochida, Ikuko; Matsunaga, Keiko; Watabe, Tadashi; Kato, Hiroki; Tatsumi, Mitsuaki; Hatazawa, Jun

2016-12-01

In boron neutron capture therapy (BNCT), positron emission tomography (PET) with 4-borono-2- 18 F-fluoro-phenylalanine (FBPA) is the only method to estimate an accumulation of 10 B to target tumor and surrounding normal tissue after administering 10 B carrier of L-paraboronophenylalanine and to search the indication of BNCT for individual patient. Absolute concentration of 10 B in tumor has been estimated by multiplying 10 B concentration in blood during BNCT by tumor to blood radioactivity (T/B) ratio derived from FBPA PET. However, the method to measure blood radioactivity either by blood sampling or image data has not been standardized. We compared image-derived blood radioactivity of FBPA with blood sampling data and studied appropriate timing and location for measuring image-derived blood counts. We obtained 7 repeated whole-body PET scans in five healthy subjects. Arterialized venous blood samples were obtained from the antecubital vein, heated in a heating blanket. Time-activity curves (TACs) of image-derived blood radioactivity were obtained using volumes of interest (VOIs) over ascending aorta, aortic arch, pulmonary artery, left and right ventricles, inferior vena cava, and abdominal aorta. Image-derived blood radioactivity was compared with those measured by blood sampling data in each location. Both the TACs of blood sampling radioactivity in each subject, and the TACs of image-derived blood radioactivity showed a peak within 5 min after the tracer injection, and promptly decreased soon thereafter. Linear relationship was found between blood sampling radioactivity and image-derived blood radioactivity in all the VOIs at any timing of data sampling (p < 0.001). Image-derived radioactivity measured in the left and right ventricles 30 min after injection showed high correlation with blood radioactivity. Image-derived blood radioactivity was lower than blood sampling radioactivity data by 20 %. Reduction of blood radioactivity of FBPA in left ventricle after 30 min of FBPA injection was minimal. We conclude that the image-derived T/B ratio can be reliably used by setting the VOI on the left ventricle at 30 min after FBPA administration and correcting for underestimation due to partial volume effect and reduction of FBPA blood radioactivity.

Pressurized capillary electrochromatographic analysis of water-soluble vitamins by combining with on-line concentration technique.

PubMed

Jia, Li; Liu, Yaling; Du, Yanyan; Xing, Da

2007-06-22

A pressurized capillary electrochromatography (pCEC) system was developed for the separation of water-soluble vitamins, in which UV absorbance was used as the detection method and a monolithic silica-ODS column as the separation column. The parameters (type and content of organic solvent in the mobile phase, type and concentration of electrolyte, pH of the electrolyte buffer, applied voltage and flow rate) affecting the separation resolution were evaluated. The combination of two on-line concentration techniques, namely, solvent gradient zone sharpening effect and field-enhanced sample stacking, was utilized to improve detection sensitivity, which proved to be beneficial to enhance the detection sensitivity by enabling the injection of large volumes of samples. Coupling electrokinetic injection with the on-line concentration techniques was much more beneficial for the concentration of positively charged vitamins. Comparing with the conventional injection mode, the enhancement in the detection sensitivities of water-soluble vitamins using the on-line concentration technique is in the range of 3 to 35-fold. The developed pCEC method was applied to evaluate water-soluble vitamins in corns.

Domoic acid excretion in dungeness crabs, razor clams and mussels.

PubMed

Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

2008-07-01

Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

Optimized and validated flow-injection spectrophotometric analysis of topiramate, piracetam and levetiracetam in pharmaceutical formulations.

PubMed

Hadad, Ghada M; Abdel-Salam, Randa A; Emara, Samy

2011-12-01

Application of a sensitive and rapid flow injection analysis (FIA) method for determination of topiramate, piracetam, and levetiracetam in pharmaceutical formulations has been investigated. The method is based on the reaction with ortho-phtalaldehyde and 2-mercaptoethanol in a basic buffer and measurement of absorbance at 295 nm under flow conditions. Variables affecting the determination such as sample injection volume, pH, ionic strength, reagent concentrations, flow rate of reagent and other FIA parameters were optimized to produce the most sensitive and reproducible results using a quarter-fraction factorial design, for five factors at two levels. Also, the method has been optimized and fully validated in terms of linearity and range, limit of detection and quantitation, precision, selectivity and accuracy. The method was successfully applied to the analysis of pharmaceutical preparations.

Recent Development in Optical Chemical Sensors Coupling with Flow Injection Analysis

PubMed Central

Ojeda, Catalina Bosch; Rojas, Fuensanta Sánchez

2006-01-01

Optical techniques for chemical analysis are well established and sensors based on these techniques are now attracting considerable attention because of their importance in applications such as environmental monitoring, biomedical sensing, and industrial process control. On the other hand, flow injection analysis (FIA) is advisable for the rapid analysis of microliter volume samples and can be interfaced directly to the chemical process. The FIA has become a widespread automatic analytical method for more reasons; mainly due to the simplicity and low cost of the setups, their versatility, and ease of assembling. In this paper, an overview of flow injection determinations by using optical chemical sensors is provided, and instrumentation, sensor design, and applications are discussed. This work summarizes the most relevant manuscripts from 1980 to date referred to analysis using optical chemical sensors in FIA.

Two-column sequential injection chromatography--new approach for fast and effective analysis and its comparison with gradient elution chromatography.

PubMed

Chocholous, Petr; Satínský, Dalibor; Sklenárová, Hana; Solich, Petr

2010-05-23

This work presents novel approach in low-pressure chromatography flow systems--two-column Sequential Injection Chromatography (2-C SIC) and its comparison with gradient elution chromatography on the same instrument. The system was equipped with two different chromatographic columns (connected to selection valve in parallel design) for isocratic separation and determination of all components in composed anti-inflammatory pharmaceutical preparation (tablets). The sample was first injected on the first column of length 30 mm where less retained analytes were separated and then the sample was injected on the second column of length 10 mm where more retained analytes were separated. The SIC system was based on a commercial SIChrom manifold (8-port high-pressure selection valve and medium-pressure syringe pump with 4 mL reservoir) (FIAlab, USA) with two commercially available monolithic columns the "first column" Chromolith Flash RP-18e (25 mm x 4.6 mm i.d. with guard column 5 mm x 4.6 mm i.d.) and the "second column" Chromolith RP-18e (10 mm x 4.6 mm i.d.) and CCD UV-vis detector USB 4000 with micro-volume 1.0 cm Z flow cell. Two mobile phases were used for analysis (one for each column). The mobile phase 1 used for elution of paracetamol, caffeine and salicylic acid (internal standard) was acetonitrile/water (10:90, v/v, the water part of pH 3.5 adjusted with acetic acid), flow rate was 0.9 mL min(-1) (volume 3.0 mL of mobile phase per analysis). The mobile phase 2 used for elution of propyphenazone was acetonitrile/water (30:70, v/v); flow rate was 1.2 mL min(-1) (volume 1.5 mL of mobile phase per analysis). Absorbance was monitored at 210 nm. Samples were prepared by dissolving of one tablet in 30% acetonitrile and 10 microL of filtered supernatant was injected on each column (2 x 10 microL). The chromatographic resolution between all compounds was >1.45 and analysis time was 5.5 min under the optimal conditions. Limits of detection were determined at 0.4 microg mL(-1) for paracetamol, at 0.5 microg mL(-1) for caffeine and at 0.7 microg mL(-1) for propyphenazone. The new two-column chromatographic set-up developed as an alternative approach to gradient elution chromatography shows evident advantages (time and solvent reduction more than one-third) as compared with single-column gradient SIC method with Chromolith Flash RP-18 (25 mm x 4.6 mm i.d. with guard column 5 mm x 4.6 mm i.d.). Copyright 2010 Elsevier B.V. All rights reserved.

Use of nitrogen to remove solvent from through oven transfer adsorption desorption interface during analysis of polycyclic aromatic hydrocarbons by large volume injection in gas chromatography.

PubMed

Áragón, Alvaro; Toledano, Rosa M; Cortés, José M; Vázquez, Ana M; Villén, Jesús

2014-04-25

The through oven transfer adsorption desorption (TOTAD) interface allows large volume injection (LVI) in gas chromatography and the on-line coupling of liquid chromatography and gas chromatography (LC-GC), enabling the LC step to be carried out in normal as well as in reversed phase. However, large amounts of helium, which is both expensive and scarce, are necessary for solvent elimination. We describe how slight modification of the interface and the operating mode allows nitrogen to be used during the solvent elimination steps. In order to evaluate the performance of the new system, volumes ranging from 20 to 100μL of methanolic solutions of four polycyclic aromatic hydrocarbons (PAHs) were sampled. No significant differences were found in the repeatability and sensitivity of the analyses of standard PAH solutions when using nitrogen or helium. The performance using the proposed modification was similar and equally satisfactory when using nitrogen or helium for solvent elimination in the TOTAD interface. In conclusion, the use of nitrogen will make analyses less expensive. Copyright © 2014 Elsevier B.V. All rights reserved.

Hydraulic Fracturing Completion Volume is Associated with Induced Earthquake Productivity in the Duvernay Play

NASA Astrophysics Data System (ADS)

Schultz, R.; Atkinson, G. M.; Eaton, D. W. S.; Gu, Y. J.; Kao, H.

2017-12-01

A sharp increase in the frequency of earthquakes near Fox Creek, Alberta began in December 2013 as a result of hydraulic fracturing completions in the Duvernay Formation. Using a newly compiled hydraulic fracturing database, we explore relationships between injection parameters and seismicity response. We find that induced earthquakes are associated with pad completions that used larger injection volumes (104-5 m3) and that seismic productivity scales linearly with injection volume. Injection pressure and rate have limited or insignificant correlation with the seismic response. Further findings suggest that geological susceptibilities play a prominent role in seismic productivity, as evidenced by spatial correlations in the seismicity patterns. Together, volume and geological susceptibilities account for 96% of the variability in the induced earthquake rate near Fox Creek. We suggest this result is fit by a modified Gutenberg-Richter earthquake frequency-magnitude distribution which provides a conceptual framework with which to forecast induced seismicity hazard.

Evaluation of performance, safety, subject acceptance, and compliance of a disposable autoinjector for subcutaneous injections in healthy volunteers.

PubMed

Berteau, Cecile; Schwarzenbach, Florence; Donazzolo, Yves; Latreille, Mathilde; Berube, Julie; Abry, Herve; Cotten, Joël; Feger, Celine; Laurent, Philippe E

2010-10-05

A disposable autoinjector was developed for subcutaneous (SC) self-injection by patients with chronic diseases. To verify its performance and evaluate its acceptance, a clinical study was conducted in healthy volunteers, comparing SC injections performed by subjects using the autoinjector with SC injections performed by nurses using a syringe. This was a randomized, single-center, crossover study comparing SC self-injection using an autoinjector with SC nurse-administered injection using a syringe. Two volumes (0.2 mL and 1 mL) were injected into healthy volunteers. Study objectives included assessment of the accuracy and consistency of the volume injected by the injection systems, and skin reaction and pain associated with the injection. The fluid depot in the SC tissue layer was evaluated by ultrasound. Subject acceptance was evaluated using questionnaires on attitudes and emotions towards the injection technique, and challenged by seeking the subjects' preferred system for a final study injection or future treatment. A total of 960 injections (480 with autoinjector, 480 with syringe) were performed in 40 subjects. There were no significant differences in mean fluid leakage and injected volumes between the systems. Pain associated with the injection was significantly lower with the auto-injector than with the syringe. Local skin reaction at the injection site was overall satisfactory. Injections were appropriately performed by all subjects. At study end, all 40 subjects preferred the autoinjector for a final study injection and for future treatment. This study indicated that the autoinjector used by the subject was similar to a syringe used by a nurse in terms of performance and safety in administering the injections, and better in terms of pain, overall acceptance, and preference.

Electrokinetic supercharging with a system-induced terminator and an optimized capillary versus electrode configuration for parts-per-trillion detection of rare-earth elements in CZE.

PubMed

Xu, Zhongqi; Kawahito, Kouji; Ye, Xiaoxue; Timerbaev, Andrei R; Hirokawa, Takeshi

2011-05-01

A further improvement of electrokinetic supercharging (EKS) methodology has been proposed, with the objective to enhance the sensitivity of the conventional CZE-UV method down to a single-digit part per trillion (ppt) level. The advanced EKS procedure is based on a novel phenomenon displaying the formation of a zone with an increased concentration of the hydrogen ion, capable to perform the function of a terminator, behind the sample zone upon electrokinetic injection. In combination with a visualizing co-ion of BGE, protonated 4-methylbenzylamine, acting as the leading ion, such system-induced terminator a effected the transient ITP state to efficiently concentrate cationic analytes prior to CZE. Furthermore, to amass more analyte ions within the effective electric field at the injection stage, a standard sample vial was replaced with an elongated vial that allowed the sample volume to be increased from 500 to 900 μL. Alongside, this replacement made the upright distance between the electrode and the capillary tips prolonged to 40.0 mm to achieve high-efficiency electrokinetic injection. The computer simulation was used for profiling analyte concentration, pH, and field strength in order to delineate formation of the terminator during sample injection. The proposed preconcentration strategy afforded an enrichment factor of 80,000 and thereby the LODs of rare-earth metal ions at the ppt level, e.g. 0.04 nM (6.7 ng/L) for erbium(III). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

How Do Deep Saline Aquifer Microbial Communities Respond to Supercritical CO2 Injection?

NASA Astrophysics Data System (ADS)

Mu, A.; Billman-Jacobe, H.; Boreham, C.; Schacht, U.; Moreau, J. W.

2011-12-01

Carbon Capture and Storage (CCS) is currently seen as a viable strategy for mitigating anthropogenic carbon dioxide pollution. The Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) is currently conducting a field experiment in the Otway Basin (Australia) studying residual gas saturation in the water-saturated reservoir of the Paaratte Formation. As part of this study, a suite of pre-CO2 injection water samples were collected from approximately 1400 meters depth (60°C, 13.8 MPa) via an in situ sampling system. The in situ sampling system isolates aquifer water from sources of contamination while maintaining the formation pressure. Whole community DNA was extracted from these samples to investigate the prokaryotic biodiversity of the saline Paaratte aquifer (EC = 1509.6 uS/cm). Bioinformatic analysis of preliminary 16S ribosomal gene data revealed Thermincola, Acinetobacter, Sphingobium, and Dechloromonas amongst the closest related genera to environmental clone sequences obtained from a subset of pre-CO2 injection groundwater samples. Epifluorescent microscopy with 4',6-diamidino-2-phenylindole (DAPI) highlighted an abundance of filamentous cells ranging from 5 to 45 μM. Efforts are currently directed towards utilising a high throughput sequencing approach to capture an exhaustive profile of the microbial diversity of the Paaratte aquifer CO2 injection site, and to understand better the response of in situ microbial populations to the injection of large volumes (e.g. many kilotonnes) of supercritical CO2 (sc-CO2). Sequencing results will be used to direct cultivation efforts towards enrichment of a CO2-tolerant microorganism. Understanding the microbial response to sc-CO2 is an integral aspect of carbon dioxide storage, for which very little information exists in the literature. This study aims to elucidate molecular mechanisms, through genomic and cultivation-based methods, for CO2 tolerance with the prospect of engineering biofilms to enhance trapping of CO2 in saline aquifers.

Determination of dioxin-like polychlorinated biphenyls in 1 mL whole blood using programmable temperature vaporization large volume injection coupled to gas chromatogram and high-resolution mass spectrometry.

PubMed

Shen, Haitao; Guan, Rongfa; Li, Jingguang; Zhang, Lei; Ren, Yiping; Xu, Xiaomin; Song, Yang; Zhao, Yunfeng; Han, Jianlong; Wu, Yongning

2013-03-12

A sensitive method based on programmable temperature vaporization large volume injection coupled to gas chromatogram and high-resolution mass spectrometry (PTV-GC-HRMS) has been developed for the determination of ultra trace levels of dioxin-like polychlorinated biphenyls (DL PCBs) in small amounts of human blood. Blood samples (1mL) were first extracted by column extraction and then purified with column chromatorgraphies. Final extracts (20μL) were introduced to the PTV injector under the solvent vent mode and detected by GC-HRMS (SIM mode). PTV parameters were observed by changing one factor at a time (practical conditions: vent flow: 50mLmin(-1), vent pressure: 0kPa and vent time: 0.1min), recoveries of most PCB congeners ranged from 55.1% to 108%, and method detection limits were in the range of 0.11-1.63pgg(-1). Copyright © 2013 Elsevier B.V. All rights reserved.

A Well-Controlled Nucleus Pulposus Tissue Culture System with Injection Port for Evaluating Regenerative Therapies.

PubMed

Arkesteijn, Irene T M; Mouser, Vivian H M; Mwale, Fackson; van Dijk, Bart G M; Ito, Keita

2016-05-01

In vitro evaluation of nucleus pulposus (NP) tissue regeneration would be useful, but current systems for NP culture are not ideal for injections. The aim of this study was to develop a long-term culture system for NP tissue that allows injections of regenerative agents. Bovine caudal NPs were harvested and placed in the newly designed culture system. After equilibration of the tissue to 0.3 MPa the volume was fixed and the tissue was cultured for 28 days. The cell viability and extracellular matrix composition remained unchanged during the culture period and gene expression profiles were similar to those obtained in earlier studies. Furthermore, to test the responsiveness of bovine caudal NPs in the system, samples were cultured for 4 days and injected twice (day 1 and 3) with (1) PBS, (2) Link-N, for regeneration, and (3) TNF-α, for degeneration. It was shown that TNF-α increased COX2 gene expression, whereas no effect of Link-N was detected. In conclusion, the newly designed system allows long-term culture of NP tissue, wherein tissue reactions to injected stimulants can be observed.

Determination of endocrine disrupting chemicals and antiretroviral compounds in surface water: A disposable sorptive sampler with comprehensive gas chromatography - Time-of-flight mass spectrometry and large volume injection with ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Wooding, Madelien; Rohwer, Egmont R; Naudé, Yvette

2017-05-05

Many rural dwellers and inhabitants of informal settlements in South Africa are without access to treated water and collect untreated water from rivers and dams for personal use. Endocrine disrupting chemicals (EDCs) have been detected in surface water and wildlife of South Africa. EDCs are often present in complex environmental matrices at ultra-trace levels complicating detection thereof. We report a simplified multi-residue approach for the detection and quantification of EDCs, emerging EDCs, and antiretroviral drugs in surface water. A low cost (less than one US dollar), disposable, sorptive extraction sampler was prepared in-house. The disposable samplers consisted of polydimethylsiloxane (PDMS) tubing fashioned into a loop which was then placed in water samples to concentrate EDCs and emerging pollutants. The PDMS samplers were thermally desorbed directly in the inlet of a GC, thereby eliminating the need for expensive consumable cryogenics. Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) was used for compound separation and identification. Linear retention indices of EDCs and emerging pollutants were determined on a proprietary Crossbond ® phase Rtx ® -CLPesticides II GC capillary column. In addition, large volume injection of surface water into an ultra-performance liquid chromatograph tandem mass spectrometer (UPLC-MS/MS) was used as complementary methodology for the detection of less volatile compounds. Large volume injection reduced tedious and costly sample preparation steps. Limits of detection for the GC method ranged from 1 to 98pg/l and for the LC method from 2 to 135ng/l. Known and emerging EDCs such as pharmaceuticals, personal care products and pesticides, as well as the antiretroviral compounds, efavirenz and nevirapine, were detected in surface water from South Africa at concentration levels ranging from 0.16ng/l to 227ng/l. Copyright © 2017 Elsevier B.V. All rights reserved.

Design, performance, and analysis of an aquifer thermal-energy-storage experiment using the doublet-well configuration

NASA Astrophysics Data System (ADS)

Molz, F. J.; Melville, J. G.; Gueven, O.; Parr, A. D.

1983-09-01

In March 1980 Auburn University began a series of aquifer thermal energy storage (ATES) experiments using the doublet well configuration. The test site was in Mobile, Alabama. The objectives of the three experimental cycles were to demonstrate the technical feasibility of the ATES concept, to identify and resolve operational problems, and to acquire a data base for developing and testing mathematical models. Pre-injection tests were performed and analyses of hydraulic, geochemical, and thermodynamic data were completed. Three injection-storage-recovery cycles had injection volumes of 25,402 m(3), 58,010 m(3), and 58,680 m(3) and average injection temperatures of 58.50C, 81.00C. and 79.00C, respectively. The first cycle injection began in February 1981 and the third cycle recovery was completed in November 1982. Attributable to the doublet well configuration no clogging of injection wells occurred. Energy recovery percentages based on recovery volumes equal to the injection volumes were 56, 45, and 42%. Thermal convection effects were observed. Aquifer nonhomogeneity, not detectable using standard aquifer testing procedures, was shown to reduce recovery efficiency.

Injection-salting of pre rigor fillets of Atlantic salmon (Salmo salar).

PubMed

Birkeland, Sveinung; Akse, Leif; Joensen, Sjurdur; Tobiassen, Torbjørn; Skåra, Torstein

2007-01-01

The effects of temperature (-1, 4, and 10 degrees C), brine concentration (12% and 25% NaCl), injection volumes, and needle densities were investigated on fillet weight gain (%), salt content (%), fillet contraction (%), and muscle gaping in pre rigor brine-injected fillets of Atlantic salmon (Salmo salar). Increased brine concentration (12% to 25%) significantly increased the initial (< 5 min after injection) and final contraction (24 h after injection) of pre rigor fillets. Increased brine concentration significantly reduced weight gain and increased salt content but had no significant effect on muscle gaping. The temperatures tested did not significantly affect weight gain, fillet contraction, or gaping score. Significant regressions (P < 0.01) between the injection volume and weight gain (range: 2.5% to 15.5%) and salt content (range: 1.7% to 6.5%) were observed for injections of pre rigor fillets. Double injections significantly increased the weight gain and salt content compared to single injections. Initial fillet contraction measured 30 min after brine injection increased significantly (P < 0.01) with increasing brine injection volume but no significant difference in the fillet contraction was observed 12 h after brine injection (range: 7.9% to 8.9%). Brine-injected post rigor control fillets obtained higher weight gain, higher salt content, more muscle gaping, and significantly lower fillet contraction compared to the pre rigor injected fillets. Injection-salting is an applicable technology as a means to obtain satisfactory salt contents and homogenously distribute the salt into the muscle of pre rigor fillets of Atlantic salmon before further processing steps such as drying and smoking.

Laser-irradiated drug chromatographic analysis and laser injection of drugs to treat staphyloccocal lesions of skin

NASA Astrophysics Data System (ADS)

Zharov, Vladimir P.; Latyshev, Alexei S.; Kovsh, Anna I.; Razumova, Svetlana A.; Masyukova, Svetlana A.; Volnukhin, Vladimir A.

2001-05-01

This article deals with further development of laser drug delivery methods. In order to estimate the effect of laser- drug interactions, we carried out the chromatographic fractionation of dexamethasone, hydrocortisone, and gentamicine, both prior to and after irradiating them by pulsed Er:YAG laser radiation. The laser radiation parameters were as follows: the wavelength, pulse energy, and pulse duration were, respectively, 2.94 micrometers , 0.7 J, and 100 microsecond(s) . The total laser radiation dose administered to a 100 (mu) l sample of these drug preparations amounted to 150 J. A chromatographic analysis revealed that drug samples exposed to Er:YAG laser radiation did not show any change. The results obtained made it possible to employ pulsed Er:YAG laser radiation to perform laser-acoustic injection of the above-mentioned drug preparations to study the treatment of staphylococcal lesions in 30 guinea pigs. The perforated channel depth was measured and the injected drug solution volume was calculated. It was found that laser injection enabled one to introduce therapeutic doses of drugs, and that it expedited the healing of lesions by 3 to 4 days, as compared to the control group that received the topical application of drugs without laser irradiation.

Cohesive Polydensified Matrix® hyaluronic acid volumizer injected for cheek augmentation has additional positive effect on nasolabial folds.

PubMed

Gauglitz, Gerd; Steckmeier, Stephanie; Pötschke, Julian; Schwaiger, Hannah

2017-01-01

Cohesive Polydensified Matrix ® hyaluronic acid (CPM-HA) volumizer has been used successfully for several years to reverse biometric volume loss during facial aging. This observational study explored the additive effect on nasolabial folds when CPM-HA volumizer is injected into the neighboring cheek area. In this open-label, prospective, postmarketing noninterventional study, 18 adult patients seeking esthetic enhancement of the lateral cheek hollows and cheekbone area were injected with CPM-HA volumizer integrated with lidocaine (CPM-HA-VL) in the upper or lower cheek area. Safety and performance of CPM-HA-VL up to 12 months after injection with follow-up visits at week 4 and month 3, 6, and 12 were assessed. The primary endpoint was improvement of cheek fullness on the validated Merz Aesthetics Scales. Additionally, changes in nasolabial folds were quantified using a phaseshift rapid in vivo measurement of skin optical three-dimensional (3D) in vivo measurement device. Patients (94.4% female, median age 52 years, age range 39-69 years) were injected with a mean volume of 2.5±1.1 mL CPM-HA-VL per side. Immediately after injection, mean severity for upper and lower cheek fullness assessed on the validated MAS improved from 2.5±0.6 and 2.8±0.5, respectively, to 1.0±0.0, and remained unchanged through month 12. Improvement in relation to baseline was attested on the Global Aesthetics Improvement Scale for all assessments. Compared with baseline, the following assessments offered a statistical significance in the reduction of wrinkle depth of nasolabial folds (maximum depth reduction by 30.4% at 3 months) according to optical 3D in vivo measurements. Pain during injection was minimal and abated within 30 minutes. Treatment was well tolerated and led to great patient satisfaction. CPM-HA-VL injected into the upper and lower cheeks led to long-lasting satisfactory cosmetic results in cheek augmentation as well as in reducing depth of nasolabial folds adjacent to the injection site.

The role of wellbore remediation on the evolution of groundwater quality from CO₂ and brine leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mansoor, Kayyum; Carroll, Susan A.; Sun, Yunwei

Long-term storage of CO₂ in underground reservoirs requires a careful assessment to evaluate risk to groundwater sources. The focus of this study is to assess time-frames required to restore water quality to pre-injection levels based on output from complex reactive transport simulations that exhibit plume retraction within a 200-year simulation period. We examined the relationship between plume volume, cumulative injected CO₂ mass, and permeability. The role of mitigation was assessed by projecting falloffs in plume volumes from their maximum peak levels with a Gaussian function to estimate plume recovery times to reach post-injection groundwater compositions. The results show a strongmore » correlation between cumulative injected CO₂ mass and maximum plume pH volumes and a positive correlation between CO₂ flux, cumulative injected CO₂, and plume recovery times, with secondary dependence on permeability.« less

The role of wellbore remediation on the evolution of groundwater quality from CO₂ and brine leakage

DOE PAGES

Mansoor, Kayyum; Carroll, Susan A.; Sun, Yunwei

2014-12-31

Long-term storage of CO₂ in underground reservoirs requires a careful assessment to evaluate risk to groundwater sources. The focus of this study is to assess time-frames required to restore water quality to pre-injection levels based on output from complex reactive transport simulations that exhibit plume retraction within a 200-year simulation period. We examined the relationship between plume volume, cumulative injected CO₂ mass, and permeability. The role of mitigation was assessed by projecting falloffs in plume volumes from their maximum peak levels with a Gaussian function to estimate plume recovery times to reach post-injection groundwater compositions. The results show a strongmore » correlation between cumulative injected CO₂ mass and maximum plume pH volumes and a positive correlation between CO₂ flux, cumulative injected CO₂, and plume recovery times, with secondary dependence on permeability.« less

A microchip-based flow injection-amperometry system with mercaptopropionic acid modified electroless gold microelectrode for the selective determination of dopamine.

PubMed

Wang, Yi; Luo, Jie; Chen, Hengwu; He, Qiaohong; Gan, Nin; Li, Tianhua

2008-09-12

A novel chip-based flow injection analysis (FIA) system has been developed for automatic, rapid and selective determination of dopamine (DA) in the presence of ascorbic acid (AA). The system is composed of a polycarbonate (PC) microfluidic chip with an electrochemical detector (ED), a gravity pump, and an automatic sample loading and injection unit. The selectivity of the ED was improved by modification of the gold working microelectrode, which was fabricated on the PC chip by UV-directed electroless gold plating, with a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA). Postplating treatment methods for cleaning the surface of electroless gold microelectrodes were investigated to ensure the formation of high quality SAMs. The effects of detection potential, flow rate, and sampling volume on the performance of the chip-based FIA system were studied. Under optimum conditions, a detection limit of 74 nmol L(-1) for DA was achieved at the sample throughput rate of 180 h(-1). A RSD of 0.9% for peak heights was observed for 19 runs of a 100 micromol L(-1) DA solution. Interference-free determination of DA could be conducted if the concentration ratio of AA-DA was no more than 10.

Insights gained from relating cumulative seismic moments to fluid injection activities

NASA Astrophysics Data System (ADS)

McGarr, A.; Barbour, A. J.

2017-12-01

The three earthquakes with magnitudes of 5 or greater that were induced in Oklahoma during 2016 motivated efforts to improve our understanding of how fluid injection operations are related to earthquake activity. In this study, we have addressed the question of whether the volume of fluid injected down wells within 10 km of the mainshock of an induced earthquake sequence can account for its total moment release. Specifically, is the total moment release equal to, or less than, twice the product of the shear modulus and the total volume injected (McGarr, JGR, 2014, equation 7)? In contrast to McGarr's (2014, equation 13) relationship for the maximum moment, M0(max), the relationship for the total moment release has the advantage of being independent of the magnitude distribution. We find that the three sequences in Oklahoma in 2016, M5.1 Fairview, M5.8 Pawnee, M5.0 Cushing, and the 2011 M5.7 Prague sequence all adhere to this relationship. We also found that eight additional sequences of earthquakes induced by various fluid injection activities, widely distributed worldwide, show the same relationship between total moment-release and injected volume. Thus, for injected volumes ranging from 103 up to 107 cubic m, the moment release of an induced earthquake sequence appears to be similarly limited. These results imply that M0(max) for a sequence induced by fluid injection could be as high as twice the product of the shear modulus and the injected volume if the mainshock in the sequence accounts for nearly all of the total moment, as was the case for the 2016 Pawnee M5.8 mainshock. This new upper bound for maximum moment is twice what was proposed by McGarr (2014, equation 13). Our new results also support the assumption in our analysis that the induced earthquake rupture is localized to the seismogenic region that is weakened owing to a pore pressure increase of the order of a seismic stress drop.

Multicapillary Gas Chromatography-Temperature Modulated Metal Oxide Semiconductor Sensors Array Detector for Monitoring of Volatile Organic Compounds in Closed Atmosphere Using Gaussian Apodization Factor Analysis.

PubMed

Alinoori, Amir Hossein; Masoum, Saeed

2018-05-22

A unique metal oxide semiconductor sensor (MOS) array detector with eight sensors was designed and fabricated in a PTFE chamber as an interface for coupling with multicapillary gas chromatography. This design consists of eight transfer lines with equal length between the multicapillary columns (MCC) and sensors. The deactivated capillary columns were passed through each transfer line and homemade flow splitter to distribute the same gas flow on each sensor. Using the eight ports flow splitter design helps us to equal the length of carrier gas path and flow for each sensor, minimizing the dead volume of the sensor's chamber and increasing chromatographic resolution. In addition to coupling of MCC to MOS array detector and other considerations in hardware design, modulation of MOS temperature was used to increase sensitivity and selectivity, and data analysis was enhanced with adapted Gaussian apodization factor analysis (GAFA) as a multivariate curve resolution algorithm. Continues air sampling and injecting system (CASI) design provides a fast and easily applied method for continues injection of air sample with no additional sample preparation. The analysis cycle time required for each run is less than 300 s. The high sample load and sharp injection with the fast separation by MCC decrease the peak widths and improve detection limits. This homemade customized instrument is an alternative to other time-consuming and expensive technologies for continuous monitoring of outgassing in air samples.

Determination of tributyltin in environmental water matrices using stir bar sorptive extraction with in-situ derivatisation and large volume injection-gas chromatography-mass spectrometry.

PubMed

Neng, N R; Santalla, R P; Nogueira, J M F

2014-08-01

Stir bar sorptive extraction with in-situ derivatization using sodium tetrahydridoborate (NaBH4) followed by liquid desorption and large volume injection-gas chromatography-mass spectrometry detection under the selected ion monitoring mode (SBSE(NaBH4)in-situ-LD/LVI-GC-MS(SIM)) was successfully developed for the determination of tributyltin (TBT) in environmental water matrices. NaBH4 proved to be an effective and easy in-situ speciation agent for TBT in aqueous media, allowing the formation of adducts with enough stability and suitable polarity for SBSE analysis. Assays performed on water samples spiked at the 10.0μg/L, yielded convenient recoveries (68.2±3.0%), showed good accuracy, suitable precision (RSD<9.0%), low detection limits (23ng/L) and excellent linear dynamic range (r(2)=0.9999) from 0.1 to 170.0µg/L, under optimized experimental conditions. By using the standard addition method, the application of the present methodology to real surface water samples allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for routine quality control analysis, easy to implement, reliable and sensitive to monitor TBT in environmental water matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-dimensional CT might be a potential evaluation modality in correction of asymmetrical masseter muscle hypertrophy by botulinum toxin injection.

PubMed

No, Yeon A; Ahn, Byeong Heon; Kim, Beom Joon; Kim, Myeung Nam; Hong, Chang Kwon

2016-01-01

For correction of this asymmetrical hypertrophy, botulinum toxin type A (BTxA) injection is one of convenient treatment modalities. Unfortunately, physical examination of masseter muscle is not enough to estimate the exact volume of muscle hypertrophy difference. Two Koreans, male and female, of bilateral masseter hypertrophy with asymmetricity were evaluated. BTxA (NABOTA(®), Daewoong, Co. Ltd., Seoul, Korea) was injected at master muscle site with total 50 U (25 U at each side) and volume change was evaluated with three-dimensional (3D) CT image analysis. Maximum reduction of masseter hypertrophy was recognized at 2-month follow-up and reduced muscle size started to restore after 3 months. Mean reduction of masseter muscle volume was 36% compared with baseline. More hypertrophied side of masseter muscle presented 42% of volume reduction at 2-month follow-up but less hypertrophied side of masseter muscle showed 30% of volume shrinkage. In conclusion, 3D CT image analysis might be the exact evaluation tool for correction of asymmetrical masseter hypertrophy by botulinum toxin injection.

Maximum magnitude earthquakes induced by fluid injection

USGS Publications Warehouse

McGarr, Arthur F.

2014-01-01

Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

Hydrologic and Geochemical Evaluation of Aquifer Storage Recovery in the Santee Limestone/Black Mingo Aquifer, Charleston, South Carolina, 1998-2002

USGS Publications Warehouse

Petkewich, Matthew D.; Parkhurst, David L.; Conlon, Kevin J.; Campbell, Bruce G.; Mirecki, June E.

2004-01-01

The hydrologic and geochemical effects of aquifer storage recovery were evaluated to determine the potential for supplying the city of Charleston, South Carolina, with large quantities of potable water during emergencies, such as earthquakes, hurricanes, or hard freezes. An aquifer storage recovery system, including a production well and three observation wells, was installed at a site located on the Charleston peninsula. The focus of this study was the 23.2-meter thick Tertiary-age carbonate and sand aquifer of the Santee Limestone and the Black Mingo Group, the northernmost equivalent of the Floridan aquifer system. Four cycles of injection, storage, and recovery were conducted between October 1999 and February 2002. Each cycle consisted of injecting between 6.90 and 7.19 million liters of water for storage periods of 1, 3, or 6 months. The volume of recovered water that did not exceed the U.S. Environmental Protection Agency secondary standard for chloride (250 milligrams per liter) varied from 1.48 to 2.46 million liters, which is equivalent to 21 and 34 percent of the total volume injected for the individual tests. Aquifer storage recovery testing occurred within two productive zones of the brackish Santee Limestone/Black Mingo aquifer. The individual productive zones were determined to be approximately 2 to 4 meters thick, based on borehole geophysical logs, electromagnetic flow-meter testing, and specific-conductance profiles collected within the observation wells. A transmissivity and storage coefficient of 37 meters squared per day and 3 x 10-5, respectively, were determined for the Santee Limestone/Black Mingo aquifer. Water-quality and sediment samples collected during this investigation documented baseline aquifer and injected water quality, aquifer matrix composition, and changes in injected/aquifer water quality during injection, storage, and recovery. A total of 193 water-quality samples were collected and analyzed for physical properties, major and minor ions, and nutrients. The aquifer and treated surface water were sodiumchloride and calcium/sodium-bicarbonate water types, respectively. Forty-five samples were collected and analyzed for total trihalomethane. Total trihalomethane data collected during aquifer storage recovery cycle 4 indicated that this constituent would not restrict the use of recovered water for drinking-water purposes. Analysis of six sediment samples collected from a cored well located near the aquifer storage recovery site showed that quartz and calcite were the dominant minerals in the Santee Limestone/Black Mingo aquifer. Estimated cation exchange capacity ranged from 12 to 36 milliequivalents per 100 grams in the lower section of the aquifer. A reactive transport model was developed that included two 2-meter thick layers to describe each of the production zones. The four layers composing the production zones were assigned porosities ranging from 0.1 to 0.3 and hydraulic conductivities ranging from 1 to 8.4 meters per day. Specific storage of the aquifer and confining units was estimated to be 1.5 x 10-5 meter-1. Longitudinal dispersivity of all layers was specified to be 0.5 meter. Leakage through the confining unit was estimated to be minimal and, therefore, not used in the reactive transport modeling. Inverse geochemical modeling indicates that mixing, cation exchange, and calcite dissolution are the dominant reactions that occur during aquifer storage recovery testing in the Santee Limestone/Black Mingo aquifer. Potable water injected into the Santee Limestone/Black Mingo aquifer evolved chemically by mixing with brackish background water and reaction with calcite and cation exchangers in the sediment. Reactive-transport model simulations indicated that the calcite and exchange reactions could be treated as equilibrium processes. Simulations with the calibrated reactive transport model indicated that approximately one-fourth of the total volume of water injected into

Analysis of poly-beta-hydroxybutyrate in environmental samples by GC-MS/MS.

PubMed

Elhottová, D; Tríska, J; Petersen, S O; Santrůcková, H

2000-05-01

Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-beta-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization of beta-hydroxybutyrate (3-OH C4:0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of beta-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10(-13) g microL(-1) of injected volume, while by GC (FID) and GC-MS (scan) it was around 10(-10) g microL(-1) of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g(-1) dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.

Induced seismicity provides insight into why earthquake ruptures stop.

PubMed

Galis, Martin; Ampuero, Jean Paul; Mai, P Martin; Cappa, Frédéric

2017-12-01

Injection-induced earthquakes pose a serious seismic hazard but also offer an opportunity to gain insight into earthquake physics. Currently used models relating the maximum magnitude of injection-induced earthquakes to injection parameters do not incorporate rupture physics. We develop theoretical estimates, validated by simulations, of the size of ruptures induced by localized pore-pressure perturbations and propagating on prestressed faults. Our model accounts for ruptures growing beyond the perturbed area and distinguishes self-arrested from runaway ruptures. We develop a theoretical scaling relation between the largest magnitude of self-arrested earthquakes and the injected volume and find it consistent with observed maximum magnitudes of injection-induced earthquakes over a broad range of injected volumes, suggesting that, although runaway ruptures are possible, most injection-induced events so far have been self-arrested ruptures.

Efficacy of basal soil injection at different water volumes and landscape settings for Asian longhorn beetle control

Treesearch

Phillip A. Lewis

2007-01-01

The Asian longhorn beetle eradication program currently treats at-risk trees by soil injection with a high volume solution of pesticide placed in concentric rings expanding out from the trunk to the dripline of the tree. Using this method in wooded habitats has previously resulted in no detectable residue in treated trees. Basal soil injection (BSI) uses a high...

Computational fluid dynamics study of viscous fingering in supercritical fluid chromatography.

PubMed

Subraveti, Sai Gokul; Nikrityuk, Petr; Rajendran, Arvind

2018-01-26

Axi-symmetric numerical simulations are carried out to study the dynamics of a plug introduced through a mixed-stream injection in supercritical fluid chromatographic columns. The computational fluid dynamics model developed in this work takes into account both the hydrodynamics and adsorption equilibria to describe the phenomena of viscous fingering and plug effect that contribute to peak distortions in mixed-stream injections. The model was implemented into commercial computational fluid dynamics software using user-defined functions. The simulations describe the propagation of both the solute and modifier highlighting the interplay between the hydrodynamics and plug effect. The simulated peaks showed good agreement with experimental data published in the literature involving different injection volumes (5 μL, 50 μL, 1 mL and 2 mL) of flurbiprofen on Chiralpak AD-H column using a mobile phase of CO 2 and methanol. The study demonstrates that while viscous fingering is the main source of peak distortions for large-volume injections (1 mL and 2 mL) it has negligible impact on small-volume injections (5 μL and 50 μL). Band broadening in small-volume injections arise mainly due to the plug effect. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Geospatial cross-correlation analysis of Oklahoma earthquakes and saltwater disposal volume 2011 - 2016

NASA Astrophysics Data System (ADS)

Pollyea, R.; Mohammadi, N.; Taylor, J. E.

2017-12-01

The annual earthquake rate in Oklahoma increased dramatically between 2009 and 2016, owing in large part to the rapid proliferation of salt water disposal wells associated with unconventional oil and gas recovery. This study presents a geospatial analysis of earthquake occurrence and SWD injection volume within a 68,420 km2 area in north-central Oklahoma between 2011 and 2016. The spatial co-variability of earthquake occurrence and SWD injection volume is analyzed for each year of the study by calculating the geographic centroid for both earthquake epicenter and volume-weighted well location. In addition, the spatial cross correlation between earthquake occurrence and SWD volume is quantified by calculating the cross semivariogram annually for a 9.6 km × 9.6 km (6 mi × 6 mi) grid over the study area. Results from these analyses suggest that the relationship between volume-weighted well centroids and earthquake centroids generally follow pressure diffusion space-time scaling, and the volume-weighted well centroid predicts the geographic earthquake centroid within a 1σ radius of gyration. The cross semivariogram calculations show that SWD injection volume and earthquake occurrence are spatially cross correlated between 2014 and 2016. These results also show that the strength of cross correlation decreased from 2015 to 2016; however, the cross correlation length scale remains unchanged at 125 km. This suggests that earthquake mitigation efforts have been moderately successful in decreasing the strength of cross correlation between SWD volume and earthquake occurrence near-field, but the far-field contribution of SWD injection volume to earthquake occurrence remains unaffected.

Method of increasing power within an optical cavity with long path lengths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leen, John Brian; Bramall, Nathan E.

A cavity-enhanced absorption spectroscopy instrument has an optical cavity with two or more cavity mirrors, one mirror of which having a hole or other aperture for injecting a light beam, and the same or another mirror of which being partially transmissive to allow exit of light to a detector. A spherical-spherical configuration with at least one astigmatic mirror or a spherical-cylindrical configuration where the spherical mirror could also be astigmatic prevents a reentrant condition wherein the injected beam would prematurely exit the cavity through the aperture. This combination substantially increases the number of passes of the injected beam through amore » sample volume for sensitive detection of chemical species even in less than ideal conditions including low power laser or LED sources, poor mirror reflectivity or detector noise at the wavelengths of interest, or cavity alignment issues such as vibration or temperature and pressure changes.« less

"Reagentless" flow injection determination of ammonia and urea using membrane separation and solid phase basification

NASA Technical Reports Server (NTRS)

Akse, J. R.; Thompson, J. O.; Sauer, R. L.; Atwater, J. E.

1998-01-01

Flow injection analysis instrumentation and methodology for the determination of ammonia and ammonium ions in an aqueous solution are described. Using in-line solid phase basification beds containing crystalline media. the speciation of ammoniacal nitrogen is shifted toward the un-ionized form. which diffuses in the gas phase across a hydrophobic microporous hollow fiber membrane into a pure-water-containing analytical stream. The two streams flow in a countercurrent configuration on opposite sides of the membrane. The neutral pH of the analytical stream promotes the formation of ammonium cations, which are detected using specific conductance. The methodology provides a lower limit of detection of 10 microgram/L and a dynamic concentration range spanning three orders of magnitude using a 315-microliters sample injection volume. Using immobilized urease to enzymatically promote the hydrolysis of urea to produce ammonia and carbon dioxide, the technique has been extended to the determination of urea.

Determination of pesticides in composite dietary samples by gas chromatography/mass spectrometry in the selected ion monitoring mode by using a temperature-programmable large volume injector with preseparation column.

PubMed

Rosenblum, L; Hieber, T; Morgan, J

2001-01-01

Use of a temperature-programmable preseparation column in the gas chromatographic (GC) injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and are Soxhlet-extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid-liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final cleanup step occurs in a preseparation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by GC/mass spectrometry (MS) in the selected ion monitoring mode. Method detection limits were at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1, 5, and 10% fat by weight. Precision over multiple injections was acceptable, with a relative standard deviation of 2.6-15% for 25 analytes.

Organochlorine contaminants in double-crested cormorants from Green Bay, WI: I. Large-scale extraction and isolation from eggs using semi-permeable membrane dialysis

USGS Publications Warehouse

Meadows, J.C.; Tillitt, D.E.; Schwartz, T.R.; Schroeder, D.J.; Echols, K.R.; Gale, R.W.; Powell, D.C.; Bursian, S.J.

1996-01-01

A 41.3-kg sample of double-crested cormorant (Phalacrocorax auritus) egg contents was extracted, yielding over 2 L of egg lipid. The double-crested cormorant (DCC) egg extract, after clean-up and concentration, was intended for use in egg injection studies to determine the embryotoxicity of the organic contaminants found within the eggs. Large-scale dialysis was used as a preliminary treatment to separate the extracted contaminants from the co-extracted sample lipids. The lipid was dialyzed in 80×5 cm semi-permeable membrane devices (SPMDs) in 50-ml aliquants. After the removal of 87 g of cholesterol by freeze-fractionation, the remaining lipid carryover (56 g) was removed by 100 routine gel permeation chromatography (GPC) operations. A 41,293-g sample was thus extracted and purified to the extent that it could easily be placed at a volume of 5 ml, the volume calculated to be necessary for the egg injection study. Analyses were performed comparing contaminant concentrations in the final purified extract to those present in the original egg material, in the extract after dialysis and cholesterol removal, and in the excluded materials. Recoveries of organochlorine pesticides through dialysis and cholesterol ranged from 96% to 135%. Total polychlorinated biphenyls in the final extract were 96% of those measured in the original egg material. Analysis of excluded lipid and cholesterol indicated that 92% of the polychlorinated dibenzo-dioxins and-furans were separated into the final extract.

Hydraulic fracturing volume is associated with induced earthquake productivity in the Duvernay play.

PubMed

Schultz, R; Atkinson, G; Eaton, D W; Gu, Y J; Kao, H

2018-01-19

A sharp increase in the frequency of earthquakes near Fox Creek, Alberta, began in December 2013 in response to hydraulic fracturing. Using a hydraulic fracturing database, we explore relationships between injection parameters and seismicity response. We show that induced earthquakes are associated with completions that used larger injection volumes (10 4 to 10 5 cubic meters) and that seismic productivity scales linearly with injection volume. Injection pressure and rate have an insignificant association with seismic response. Further findings suggest that geological factors play a prominent role in seismic productivity, as evidenced by spatial correlations. Together, volume and geological factors account for ~96% of the variability in the induced earthquake rate near Fox Creek. This result is quantified by a seismogenic index-modified frequency-magnitude distribution, providing a framework to forecast induced seismicity. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Particulate-matter content of 11 cephalosporin injections: conformance with USP limits.

PubMed

Parkins, D A; Taylor, A J

1987-05-01

The particulate-matter content of 11 dry-powder cephalosporin injections was determined using a modified version of the official United States Pharmacopeial Convention (USP) method for particulate matter in small-volume injections (SVIs). Ten vials of each cephalosporin product were each constituted with 10 mL of Water for Injections BP that had been filtered through a 0.22-micron membrane. The pooled contents of the 10 vials for each product were allowed to stand under reduced pressure to ensure removal of gas bubbles. Particulate-matter content was determined using a HIAC/Royco particle counter on six 10-mL samples obtained from the pooled solutions for each product. All solution preparation and particle counting was performed in a horizontal-laminar-airflow hood. Modifications of the USP method used in this study included the use of six rather than two samples from each pooled solution, the addition of diluent to the injections through the rubber closure with a needle instead of into the open container, and changes in the degassing method. Particle counts for all products examined were lower than USP limits for SVIs. All but two products contained less than 15% of USP limits for particles greater than or equal to 10 microns in effective diameter and particles greater than or equal to 25 microns in effective diameter. The standard USP method for degassing (standing for two minutes) was inadequate. Application of reduced pressure for up to 10 minutes was necessary for thorough degassing of products.(ABSTRACT TRUNCATED AT 250 WORDS)

Note: Four-port microfluidic flow-cell with instant sample switching

NASA Astrophysics Data System (ADS)

MacGriff, Christopher A.; Wang, Shaopeng; Tao, Nongjian

2013-10-01

A simple device for high-speed microfluidic delivery of liquid samples to a surface plasmon resonance sensor surface is presented. The delivery platform is comprised of a four-port microfluidic cell, two ports serve as inlets for buffer and sample solutions, respectively, and a high-speed selector valve to control the alternate opening and closing of the two outlet ports. The time scale of buffer/sample switching (or sample injection rise and fall time) is on the order of milliseconds, thereby minimizing the opportunity for sample plug dispersion. The high rates of mass transport to and from the central microfluidic sensing region allow for SPR-based kinetic analysis of binding events with dissociation rate constants (kd) up to 130 s-1. The required sample volume is only 1 μL, allowing for minimal sample consumption during high-speed kinetic binding measurement.

Induced seismicity provides insight into why earthquake ruptures stop

PubMed Central

Galis, Martin; Ampuero, Jean Paul; Mai, P. Martin; Cappa, Frédéric

2017-01-01

Injection-induced earthquakes pose a serious seismic hazard but also offer an opportunity to gain insight into earthquake physics. Currently used models relating the maximum magnitude of injection-induced earthquakes to injection parameters do not incorporate rupture physics. We develop theoretical estimates, validated by simulations, of the size of ruptures induced by localized pore-pressure perturbations and propagating on prestressed faults. Our model accounts for ruptures growing beyond the perturbed area and distinguishes self-arrested from runaway ruptures. We develop a theoretical scaling relation between the largest magnitude of self-arrested earthquakes and the injected volume and find it consistent with observed maximum magnitudes of injection-induced earthquakes over a broad range of injected volumes, suggesting that, although runaway ruptures are possible, most injection-induced events so far have been self-arrested ruptures. PMID:29291250

Body water compartments during bed rest: Evaluation of analytical methods

NASA Technical Reports Server (NTRS)

Young, H. L.; Juhos, L.; Castle, B. L.; Yusken, J.; Greenleaf, J. E.

1973-01-01

Nine healthy young men were studied to determine the reproducibility and interchangeability of the use of radio-iodinated human serum albumin and Evans Blue dye for estimating plasma volume, sodium bromide for extracellular fluid volume, and deuterium oxide for total body water volume. All subjects were tested in a semibasal condition and allowed to rest for at least 30 min. after arriving at the laboratory. The results indicate that there was uniform distribution of I131 and Evans Blue dye 10 min. after injection and of NaBr and D2O 3 hours after oral ingestion; the buildup of residual tracer did not interfere appreciably with the measurement of either or Evans Blue spaces when they are administered at equal intervals, and the buildup of background tracer after ingestion of NaBr and D2O once per week for three consecutive weeks did not affect the accuracy of the measurement. It was found that I131 and Evans Blue may be used interchangeably for estimating plasma volume; for estimating bromide and D2O spaces, one 3-hour equilibrium blood sample gives results similar to the extrapolation of multiple samples.

Overcoming the Practical Barriers to Spinal Cord Cell Transplantation for ALS

DTIC Science & Technology

2013-10-01

not be neglected. Moreover, escalating numbers and volumes of injections seem to be associated with lack of accuracy and reflux . Histological...with intact segments. Histological analysis will also determine whether reflux occurs with volume escalation as well as with fast (hand-held...analysis of reflux and transient morbidity with number and volume of injection of hNPCs (Boulis). Create a cell bank of astrocyte restricted

Dispersive liquid-liquid microextraction for the determination of vitamins D and K in foods by liquid chromatography with diode-array and atmospheric pressure chemical ionization-mass spectrometry detection.

PubMed

Viñas, Pilar; Bravo-Bravo, María; López-García, Ignacio; Hernández-Córdoba, Manuel

2013-10-15

A simple and rapid method was developed using reversed-phase liquid chromatography (LC) with both diode array (DAD) and atmospheric pressure chemical ionization mass spectrometric (APCI-MS) detection, for the simultaneous analysis of the vitamins ergocalciferol (D2), cholecalciferol (D3), phylloquinone (K1), menaquinone-4 (K2) and a synthetic form of vitamin K, menadione (K3). The Taguchi experimental method, an orthogonal array design (OAD), was used to optimize an efficient and clean preconcentration step based on dispersive liquid-liquid microextraction (DLLME). A factorial design was applied with six factors and three levels for each factor, namely, carbon tetrachloride volume, methanol volume, aqueous sample volume, pH of sample, sodium chloride concentration and time of the centrifugation step. The DLLME optimized procedure consisted of rapidly injecting 3 mL of acetonitrile (disperser solvent) containing 150 µL carbon tetrachloride (extraction solvent) into the aqueous sample, thereby forming a cloudy solution. Phase separation was performed by centrifugation, and the sedimented phase was evaporated with nitrogen, reconstituted with 50 µL of acetonitrile, and injected. The LC analyses were carried out using a mobile phase composed of acetonitrile, 2-propanol and water, under gradient elution. Quantification was carried out by the standard additions method. The APCI-MS spectra, in combination with UV spectra, permitted the correct identification of compounds in the food samples. The method was validated according to international guidelines and using a certified reference material. The validated method was applied for the analysis of vitamins D and K in infant foods and several green vegetables. There was little variability in the forms of vitamin K present in vegetables, with the most abundant vitamer in all the samples being phylloquinone, while menadione could not be detected. Conversely, cholecalciferol, which is present in food of animal origin, was the main form in infant foods, while ergocalciferol was not detected. Copyright © 2013 Elsevier B.V. All rights reserved.

High-throughput microcoil NMR of compound libraries using zero-dispersion segmented flow analysis.

PubMed

Kautz, Roger A; Goetzinger, Wolfgang K; Karger, Barry L

2005-01-01

An automated system for loading samples into a microcoil NMR probe has been developed using segmented flow analysis. This approach enhanced 2-fold the throughput of the published direct injection and flow injection methods, improved sample utilization 3-fold, and was applicable to high-field NMR facilities with long transfer lines between the sample handler and NMR magnet. Sample volumes of 2 microL (10-30 mM, approximately 10 microg) were drawn from a 96-well microtiter plate by a sample handler, then pumped to a 0.5-microL microcoil NMR probe as a queue of closely spaced "plugs" separated by an immiscible fluorocarbon fluid. Individual sample plugs were detected by their NMR signal and automatically positioned for stopped-flow data acquisition. The sample in the NMR coil could be changed within 35 s by advancing the queue. The fluorocarbon liquid wetted the wall of the Teflon transfer line, preventing the DMSO samples from contacting the capillary wall and thus reducing sample losses to below 5% after passage through the 3-m transfer line. With a wash plug of solvent between samples, sample-to-sample carryover was <1%. Significantly, the samples did not disperse into the carrier liquid during loading or during acquisitions of several days for trace analysis. For automated high-throughput analysis using a 16-second acquisition time, spectra were recorded at a rate of 1.5 min/sample and total deuterated solvent consumption was <0.5 mL (1 US dollar) per 96-well plate.

Flow injection method for the determination of silver concentration in drinking water for spacecrafts.

PubMed

Bruzzoniti, Maria Concetta; Kobylinska, Dorota Korte; Franko, Mladen; Sarzanini, Corrado

2010-04-14

A flow injection method has been developed for determination of silver. The method is based on a reduction reaction with sodium borohydride which leads to the formation of a colloidal species which is monitored at a wavelength of 390 nm. The reaction variables flow rate, sodium borohydride concentration and pH, which affect sensitivity, were investigated and their effects were established using a two-levels, three-factor experimental design. Further optimization of manifold variables (reaction coil and injection volume) allowed us to determine silver in the range 0.050-5.0 mg L(-1) with a minimum detectable concentration of 0.050 mg L(-1). Silver is added, as biocide, to drinking water for spacecrafts. The chemical species of silver, present in this kind of sample, were characterized by a procedure based on the selective retention of Ag(+) onto a 2.2.2. cryptand based substrate followed by determination of the non-bound and bound (after elution) Ag(+) by the FIA method. The method optimized was applied to a drinking water sample provided for the launch with the Automated Transfer Vehicle (ATV) module Jule Verne to the International Space Station (March 9, 2008). Copyright 2010 Elsevier B.V. All rights reserved.

Determination of mercury in agroindustrial samples by flow-injection cold vapor atomic absorption spectrometry using ion exchange and reductive elution.

PubMed

Gomes Neto, J A; Zara, L F; Rocha, J C; Santos, A; Dakuzaku, C S; Nóbrega, J A

2000-03-06

A flow-injection system with a Chelite-S(R) cationic resin packed minicolumn is proposed for the determination of trace levels of mercury in agroindustrial samples by cold vapor atomic absorption spectrometry. Improved sensitivity and selectivity are attained since mercuric ions are on-line concentrated whereas other potential interferents are discarded. With on-line reductive elution procedure, concentrated hydrochloric acid could be replaced by 10% w/v SnCl(2), in 6 M HCl as eluent. The reversed-intermittent stream either carries the atomic mercury to the flow cell in the forward direction or removes the residue from reactor/gas-liquid separator to a discarding flask in the opposite direction. Concentration and volume of reagent, acidity, flow rates, commutation times and potential interfering species were investigated. For 120 s preconcentration time, the proposed system handles about 25 samples h(-1) (50.0-500 ng l(-1)), consuming about 10 ml sample and 5 mg SnCl(2) per determination. The detection limit is 0.8 ng l(-1) and the relative standard deviation (RSD) (n=12) of a 76.7 ng l(-1) sample is about 5%. Results are in agreement with certified value of standard materials at 95% confidence level and good recoveries (97-128%) of spiked samples were found.

ANALYSIS OF LOW-LEVEL PESTICIDES FROM HIGH-ELEVATION LAKE WATERS BY LARGE VOLUME INJECTION GCMS

EPA Science Inventory

This paper describes the method development for the determination of ultra-low level pesticides from high-elevation lake waters by large-volume injection programmable temperature vaporizer (LVI-PTV) GC/MS. This analytical method is developed as a subtask of a larger study, backgr...

Single well surfactant test to evaluate surfactant floods using multi tracer method

DOEpatents

Sheely, Clyde Q.

1979-01-01

Data useful for evaluating the effectiveness of or designing an enhanced recovery process said process involving mobilizing and moving hydrocarbons through a hydrocarbon bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well, comprising (a) determining hydrocarbon saturation in a volume in the formation near a well bore penetrating formation, (b) injecting sufficient mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore, and (c) determining the hydrocarbon saturation in a volume including at least a part of the volume of (b) by an improved single well surfactant method comprising injecting 2 or more slugs of water containing the primary tracer separated by water slugs containing no primary tracer. Alternatively, the plurality of ester tracers can be injected in a single slug said tracers penetrating varying distances into the formation wherein the esters have different partition coefficients and essentially equal reaction times. The single well tracer method employed is disclosed in U.S. Pat. No. 3,623,842. This method designated the single well surfactant test (SWST) is useful for evaluating the effect of surfactant floods, polymer floods, carbon dioxide floods, micellar floods, caustic floods and the like in subterranean formations in much less time and at much reduced cost compared to conventional multiwell pilot tests.

Unified method for serial study of body fluid compartments

NASA Technical Reports Server (NTRS)

Spears, C. P.; Hyatt, K. H.; Vogel, J. M.; Langfitt, S. B.

1974-01-01

Methods for the simultaneous determination of equilibrium space of I-125/RISA(radio-iodinated serum albumin) (plasma volume), Cr-51 red cell mass, Br-82 space (extracellular fluid volume), and tritiated water space (total body water) are described. Determinations were made on two occasions separated by a 1 week interval in 43 healthy young men who were on a strict metabolic diet. Hourly samples were taken for 6 hours after injection of the radionuclides. Correlation of these values to the inscribed exponential disappearance curve was high. In 15 subjects, earlier and more-frequent sampling led to no improvement in the accuracy of estimation of the I-125/RISA space. Use of this method gave results in 12 subjects for Br-82 space and in 11 subjects for tritiated water space which were not significantly different from those obtained by correction for urine loss.

Nanocapillaries for Open Tubular Chromatographic Separations of Proteins in Femtoliter to Picoliter Samples

PubMed Central

Wang, Xiayan; Cheng, Chang; Wang, Shili; Zhao, Meiping; Dasgupta, Purnendu K.; Liu, Shaorong

2009-01-01

We have recently examined the potential of bare nanocapillaries for free solution DNA separations and demonstrated efficiencies exceeding 106 theoretical plates/m. In the present work, we demonstrate the use of bare and hydroxypropylcellulose (HPC) coated open tubular nanocapillaries for protein separations. Using 1.5 μm inner diameter (i.d.) capillary columns, hydrodynamically injecting femto to picoliter (fL-pL) volumes of fluorescent or fluorescent dye labeled protein samples, utilizing a pneumatically pressurized chamber containing 1.0 mM sodium tetraborate solution eluent (typ. 200 psi) as the pump and performing on-column detection using a simple laser-induced fluorescence detector, we demonstrate efficiencies of close to a million theoretical plates/m while generating single digit μL volumes of waste for a complete chromatographic run. We achieve baseline resolution for a protein mixture consisting of transferrin, α-lactalbumin, insulin, and α -2-macroglobulin. PMID:19663450

Simple flow injection colorimetric system for determination of paraquat in natural water.

PubMed

Chuntib, Prakit; Jakmunee, Jaroon

2015-11-01

A simple and low cost flow injection colorimetric system has been developed for determination of paraquat in natural water. The developed method is based on the reduction of paraquat by using sodium dithionite as a reducing agent in an alkaline medium to produce a blue free radical ion that can be detected by a simple light emitting diode-light dependent resistor (LED-LDR) colorimeter. The standard or sample solution was injected via a set of 3-way solenoid valves into a water carrier stream and flowed to merge with reagent to generate a colored product which is proportional to the concentration of paraquat ion in the solution. Under the optimum condition of the system, i.e., mixing coil length 30 cm, flow rate 2.0 mL min(-1), sample volume 100 μL, concentrations of dithionite 0.1% (w/v) and sodium hydroxide 0.06 mol L(-1), a linear calibration graph in the range of 0.2-10.0 mg L(-1) with a correlation coefficient of 0.9996, and a limit of detection of 0.15 mg L(-1) were achieved. Relative standard deviation for 9 replicate injections of 1 mg L(-1) paraquat is 3.7%. A sample throughput of 40 injections h(-1) was achieved. The limit of detection can be improved by off-line preconcentration of paraquat employing a column packed with Dowex 50WX8-100 (H) cation exchange resin and eluted with 10% (w/v) ammonium chloride in ammonium buffer solution pH 10. The eluting solution was then injected into the FI system for paraquat determination. The proposed system did not suffer from interferences of some possible ions in natural water and other herbicides. Recoveries obtained by spiking 0.5 and 5.0 mg L(-1) paraquat standard into water samples were in the range of 104-110% and 101-105%, respectively. The developed system can be conveniently applied for screening of paraquat contaminated in natural water. Copyright © 2015 Elsevier B.V. All rights reserved.

Extraction and Determination of Cyproheptadine in Human Urine by DLLME-HPLC Method.

PubMed

Maham, Mehdi; Kiarostami, Vahid; Waqif-Husain, Syed; Abroomand-Azar, Parviz; Tehrani, Mohammad Saber; Khoeini Sharifabadi, Malihe; Afrouzi, Hossein; Shapouri, Mahmoudreza; Karami-Osboo, Rouhollah

2013-01-01

Novel dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography with photodiode array detection (HPLC-DAD) has been applied for the extraction and determination of cyproheptadine (CPH), an antihistamine, in human urine samples. In this method, 0.6 mL of acetonitrile (disperser solvent) containing 30 μL of carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5 mL urine sample. After centrifugation, the sedimented phase containing enriched analyte was dissolved in acetonitrile and an aliquot of this solution injected into the HPLC system for analysis. Development of DLLME procedure includes optimization of some important parameters such as kind and volume of extraction and disperser solvent, pH and salt addition. The proposed method has good linearity in the range of 0.02-4.5 μg mL(-1) and low detection limit (13.1 ng mL(-1)). The repeatability of the method, expressed as relative standard deviation was 4.9% (n = 3). This method has also been applied to the analysis of real urine samples with satisfactory relative recoveries in the range of 91.6-101.0%.

Ring-oven based preconcentration technique for microanalysis: simultaneous determination of Na, Fe, and Cu in fuel ethanol by laser induced breakdown spectroscopy.

PubMed

Cortez, Juliana; Pasquini, Celio

2013-02-05

The ring-oven technique, originally applied for classical qualitative analysis in the years 1950s to 1970s, is revisited to be used in a simple though highly efficient and green procedure for analyte preconcentration prior to its determination by the microanalytical techniques presently available. The proposed preconcentration technique is based on the dropwise delivery of a small volume of sample to a filter paper substrate, assisted by a flow-injection-like system. The filter paper is maintained in a small circular heated oven (the ring oven). Drops of the sample solution diffuse by capillarity from the center to a circular area of the paper substrate. After the total sample volume has been delivered, a ring with a sharp (c.a. 350 μm) circular contour, of about 2.0 cm diameter, is formed on the paper to contain most of the analytes originally present in the sample volume. Preconcentration coefficients of the analyte can reach 250-fold (on a m/m basis) for a sample volume as small as 600 μL. The proposed system and procedure have been evaluated to concentrate Na, Fe, and Cu in fuel ethanol, followed by simultaneous direct determination of these species in the ring contour, employing the microanalytical technique of laser induced breakdown spectroscopy (LIBS). Detection limits of 0.7, 0.4, and 0.3 μg mL(-1) and mean recoveries of (109 ± 13)%, (92 ± 18)%, and (98 ± 12)%, for Na, Fe, and Cu, respectively, were obtained in fuel ethanol. It is possible to anticipate the application of the technique, coupled to modern microanalytical and multianalyte techniques, to several analytical problems requiring analyte preconcentration and/or sample stabilization.

Pharmacokinetics of enrofloxacin and ciprofloxacin in Atlantic horseshoe crabs (Limulus polyphemus) after single injection.

PubMed

Kirby, A; Lewbart, G A; Hancock-Ronemus, A; Papich, M G

2018-04-01

The pharmacokinetics of enrofloxacin and the metabolite ciprofloxacin were studied in horseshoe crabs after a single injection of 5 mg/kg. Twelve Atlantic horseshoe crabs (Limulus polyphemus) of undetermined age were injected with enrofloxacin into the dorsal cardiac sinus. Hemolymph samples were collected by syringe and needle at regular intervals for 120 hr. Samples were analyzed by high-pressure liquid chromatography and compartmental analysis performed on the results. Following injection, the elimination half-life (T½), peak concentration, area under the curve (AUC), and volume of distribution (VD) for enrofloxacin were 27.9 (29.13) hr, 8.98 (18.09) μg/ml, 367.38 (35.41) hr μg/ml, and 0.575 (20.48) L/kg, respectively (mean value, CV%). For ciprofloxacin, the elimination T½, peak concentration, and AUC were 61.36 (34.55) hr, 2.34 (24.11) μg/ml, and 304.46 (24.69) μg hr/ml. In these animals, the ciprofloxacin concentrations comprised an average of 45.8% of the total fluoroquinolone concentrations, which is substantial compared to other marine invertebrates. The total AUC produced (sum of enrofloxacin and ciprofloxacin) was 682.69 ± 180.61 μg hr/ml. Concentrations that were achieved after a single dose of 5 mg/kg horseshoe crabs were sufficient to treat bacteria susceptible to enrofloxacin and ciprofloxacin. © 2017 John Wiley & Sons Ltd.

Development of a filter to prevent infections with spore-forming bacteria in injecting drug users.

PubMed

Alhusein, Nour; Scott, Jenny; Kasprzyk-Hordern, Barbara; Bolhuis, Albert

2016-12-01

In heroin injectors, there have been a number of outbreaks caused by spore-forming bacteria, causing serious infections such as anthrax or botulism. These are, most likely, caused by injecting contaminated heroin, and our aim was to develop a filter that efficiently removes these bacteria and is also likely to be acceptable for use by people who inject drugs (i.e. quick, simple and not spoil the hit). A prototype filter was designed and different filter membranes were tested to assess the volume of liquid retained, filtration time and efficiency of the filter at removing bacterial spores. Binding of active ingredients of heroin to different types of membrane filters was determined using a highly sensitive analytical chemistry technique. Heroin samples that were tested contained up to 580 bacteria per gramme, with the majority being Bacillus spp., which are spore-forming soil bacteria. To remove these bacteria, a prototype filter was designed to fit insulin-type syringes, which are commonly used by people who inject drugs (PWIDs). Efficient filtration of heroin samples was achieved by combining a prefilter to remove particles and a 0.22 μm filter to remove bacterial spores. The most suitable membrane was polyethersulfone (PES). This membrane had the shortest filtration time while efficiently removing bacterial spores. No or negligible amounts of active ingredients in heroin were retained by the PES membrane. This study successfully produced a prototype filter designed to filter bacterial spores from heroin samples. Scaled up production could produce an effective harm reduction tool, especially during outbreaks such as occurred in Europe in 2009/10 and 2012.

Automated Microflow NMR: Routine Analysis of Five-Microliter Samples

PubMed Central

Jansma, Ariane; Chuan, Tiffany; Geierstanger, Bernhard H.; Albrecht, Robert W.; Olson, Dean L.; Peck, Timothy L.

2006-01-01

A microflow CapNMR probe double-tuned for 1H and 13C was installed on a 400-MHz NMR spectrometer and interfaced to an automated liquid handler. Individual samples dissolved in DMSO-d6 are submitted for NMR analysis in vials containing as little as 10 μL of sample. Sets of samples are submitted in a low-volume 384-well plate. Of the 10 μL of sample per well, as with vials, 5 μL is injected into the microflow NMR probe for analysis. For quality control of chemical libraries, 1D NMR spectra are acquired under full automation from 384-well plates on as many as 130 compounds within 24 h using 128 scans per spectrum and a sample-to-sample cycle time of ∼11 min. Because of the low volume requirements and high mass sensitivity of the microflow NMR system, 30 nmol of a typical small molecule is sufficient to obtain high-quality, well-resolved, 1D proton or 2D COSY NMR spectra in ∼6 or 20 min of data acquisition time per experiment, respectively. Implementation of pulse programs with automated solvent peak identification and suppression allow for reliable data collection, even for samples submitted in fully protonated DMSO. The automated microflow NMR system is controlled and monitored using web-based software. PMID:16194121

Persulfate injection into a gasoline source zone

NASA Astrophysics Data System (ADS)

Sra, Kanwartej S.; Thomson, Neil R.; Barker, Jim F.

2013-07-01

One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O82 -, SO42 -, Na+, dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for > 10 months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in M indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M increased by > 100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone.

Sampling and physical characterization of diesel exhaust aerosols. SAE Paper 770720

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verrant, J.A.; Kittelson, D.A.

Diesel exhaust aerosols are highly dynamic and therefore, difficult to sample without introducing falsification. This paper describes a study of these aerosols using a rapid dilution sampling system and an electrical aerosol analyzer. An Onan single cylinder indirect injection engine was used as an exhaust source. The sampler diluted the exhaust with clean air in ratios of 400:1 to 600:1 in order to prevent sample falsification by condensation and coagulation. The electrical aerosol analyzer was used to determine particle size and concentration. Volume concentration in the exhaust ranged from 2000 to 50,000 ..mu.. m/sup 3/ cm/sup -3/ which correspond tomore » mass loadings of 2.0 to 50 mg m/sup -3/ (assuming a density of 1 gm cm/sup -3/). Volume geometric mean diameters ranged from 0.12 to 0.19 ..mu..m. Evaporation and coagulation effects on diesel aerosols were observed by aging in a Teflon holding bag. A simple evaporation model was fit to the decrease of aerosol volume concentration with time. The fit revealed that the aerosols evaporated as if they were composed of normal paraffins in the 350 to 500 molecular weight range. Although the sample dilution system used in this study may alter the sample somewhat, it is probably analogous to what happens at the tailpipe of a vehicle. Measurements taken on a test track in the exhaust plume of a Peugeot 504 diesel showed aerosol size distributions very similar to those measured in our laboratory studies.« less

Waterflood control system for maximizing total oil recovery

DOEpatents

Patzek, Tadeusz Wiktor; Silin, Dimitriy Borisovic; De, Asoke Kumar

2005-06-07

A control system and method for determining optimal fluid injection pressure is based upon a model of a growing hydrofracture due to waterflood injection pressure. This model is used to develop a control system optimizing the injection pressure by using a prescribed injection goal coupled with the historical times, pressures, and volume of injected fluid at a single well. In this control method, the historical data is used to derive two major flow components: the transitional component, where cumulative injection volume is scaled as the square root of time, and a steady-state breakthrough component, which scales linearly with respect to time. These components provide diagnostic information and allow for the prevention of rapid fracture growth and associated massive water break through that is an important part of a successful waterflood, thereby extending the life of both injection and associated production wells in waterflood secondary oil recovery operations.

Waterflood control system for maximizing total oil recovery

DOEpatents

Patzek, Tadeusz Wiktor [Oakland, CA; Silin, Dimitriy Borisovich [Pleasant Hill, CA; De, Asoke Kumar [San Jose, CA

2007-07-24

A control system and method for determining optimal fluid injection pressure is based upon a model of a growing hydrofracture due to waterflood injection pressure. This model is used to develop a control system optimizing the injection pressure by using a prescribed injection goal coupled with the historical times, pressures, and volume of injected fluid at a single well. In this control method, the historical data is used to derive two major flow components: the transitional component, where cumulative injection volume is scaled as the square root of time, and a steady-state breakthrough component, which scales linearly with respect to time. These components provide diagnostic information and allow for the prevention of rapid fracture growth and associated massive water break through that is an important part of a successful waterflood, thereby extending the life of both injection and associated production wells in waterflood secondary oil recovery operations.

Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

PubMed

Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

2009-08-15

A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

Abobotulinum - a toxin injection in patients with refractory idiopathic detrusor overactivity: injections in detrusor, trigone and bladder neck or prostatic urethra, versus detrusor - only injections

PubMed Central

Emami, Maryam; Shadpour, Pejman; Kashi, Amir H.; Choopani, Masoud; Zeighami, Mohammadreza

2017-01-01

ABSTRACT Purpose: To evaluate if the injections of abobotulinum-A toxin in trigone and bladder neck/prostatic urethra in addition to detrusor provides better symptoms relief and urodynamic findings in patients with idiopathic detrusor overactivity (IDO) refractory to medical treatment. Materials and Methods: A total of 74 patients with IDO refractory to anticholinergics received injections in detrusor, trigone and bladder neck/prostatic urethra (Group A, N=36) versus detrusor only injections (Group B, N=38) of abobotulinum-A toxin. All patients were evaluated by a standard overactive bladder symptom score (OABSS) questionnaire and cystometrography before and 6 weeks after the operation. OABSS questionnaire was also completed 20 weeks after the operation. Results: The magnitude of OABSS reduction from baseline to 6 weeks after operation in groups A and B patients was 13.4±2.2 versus 11.7±2.1 (p=0.001). Cystometry results were similar in both groups except for higher volume at urgent desire to void in Group B patients (p <0.001). The mean±SD change in residual volume in Group A at 6 weeks after the operation was −4.8±28.6mL (p=0.33) compared to 21.3±16.9mL in Group B patients (p <0.001). Conclusions: In patients with IDO, adding trigone, and bladder neck/prostatic urethra as sites of abobotulinum- A toxin injection produces greater reductions in OABSS score and less residual urine volume but a lower volume at urgent desire to void in comparison with detrusor only injections. PMID:28727385

In vivo comparison of simultaneous versus sequential injection technique for thermochemical ablation in a porcine model.

PubMed

Cressman, Erik N K; Shenoi, Mithun M; Edelman, Theresa L; Geeslin, Matthew G; Hennings, Leah J; Zhang, Yan; Iaizzo, Paul A; Bischof, John C

2012-01-01

To investigate simultaneous and sequential injection thermochemical ablation in a porcine model, and compare them to sham and acid-only ablation. This IACUC-approved study involved 11 pigs in an acute setting. Ultrasound was used to guide placement of a thermocouple probe and coaxial device designed for thermochemical ablation. Solutions of 10 M acetic acid and NaOH were used in the study. Four injections per pig were performed in identical order at a total rate of 4 mL/min: saline sham, simultaneous, sequential, and acid only. Volume and sphericity of zones of coagulation were measured. Fixed specimens were examined by H&E stain. Average coagulation volumes were 11.2 mL (simultaneous), 19.0 mL (sequential) and 4.4 mL (acid). The highest temperature, 81.3°C, was obtained with simultaneous injection. Average temperatures were 61.1°C (simultaneous), 47.7°C (sequential) and 39.5°C (acid only). Sphericity coefficients (0.83-0.89) had no statistically significant difference among conditions. Thermochemical ablation produced substantial volumes of coagulated tissues relative to the amounts of reagents injected, considerably greater than acid alone in either technique employed. The largest volumes were obtained with sequential injection, yet this came at a price in one case of cardiac arrest. Simultaneous injection yielded the highest recorded temperatures and may be tolerated as well as or better than acid injection alone. Although this pilot study did not show a clear advantage for either sequential or simultaneous methods, the results indicate that thermochemical ablation is attractive for further investigation with regard to both safety and efficacy.

Development of a large volume injection method using a programmed temperature vaporization injector - gas chromatography hyphenated to ICP-MS for the simultaneous determination of mercury, tin and lead species at ultra-trace levels in natural waters.

PubMed

Terán-Baamonde, J; Bouchet, S; Tessier, E; Amouroux, D

2018-04-27

The current EU legislation lays down Environmental Quality Standards (EQS) for 45 priority substances in surface waters; among them levels for (organo)metallic species of Hg, Sn and Pb are set between ng L -1 (for Hg and Sn) and μg L -1 (for Pb). To date, only a few analytical methods can reach these very restrictive limits and there is thus a need for comprehensive methods able to analyze these species down to these levels in natural waters. The aim of this work was to develop an online automated pre-concentration method using large volume injections with a Programmed Temperature Vaporization (PTV) injector fitted with a sorbent packed liner coupled to GC-ICP-MS to further improve the detection limits associated to this well-established method. The influence of several parameters such as the PTV transfer temperature and time, carrier gas flow rate and amount of packing material was investigated. Finally, the maximum volume injected through single or multiple injection modes was optimized to obtain the best compromise between chromatographic resolution and sensitivity. After optimization, very satisfactory results in terms of absolute and methodological detection limits were achieved, down to the pg L -1 level for all species studied. The potential of the method was exemplified by determining the concentrations of organometallic compounds in unpolluted river waters samples from the Adour river basin (SW France) and results were compared with conventional (splitless) GC-ICP-MS. The strength of this analytical method lies in the low detection limits reached for the simultaneous analysis of a wide group of organometallic compounds, and the potential to transfer this method to other gas chromatographic applications with inherent lower sensitivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantification of 18F-fluorocholine kinetics in patients with prostate cancer.

PubMed

Verwer, Eline E; Oprea-Lager, Daniela E; van den Eertwegh, Alfons J M; van Moorselaar, Reindert J A; Windhorst, Albert D; Schwarte, Lothar A; Hendrikse, N Harry; Schuit, Robert C; Hoekstra, Otto S; Lammertsma, Adriaan A; Boellaard, Ronald

2015-03-01

Choline kinase is upregulated in prostate cancer, resulting in increased (18)F-fluoromethylcholine uptake. This study used pharmacokinetic modeling to validate the use of simplified methods for quantification of (18)F-fluoromethylcholine uptake in a routine clinical setting. Forty-minute dynamic PET/CT scans were acquired after injection of 204 ± 9 MBq of (18)F-fluoromethylcholine, from 8 patients with histologically proven metastasized prostate cancer. Plasma input functions were obtained using continuous arterial blood-sampling as well as using image-derived methods. Manual arterial blood samples were used for calibration and correction for plasma-to-blood ratio and metabolites. Time-activity curves were derived from volumes of interest in all visually detectable lymph node metastases. (18)F-fluoromethylcholine kinetics were studied by nonlinear regression fitting of several single- and 2-tissue plasma input models to the time-activity curves. Model selection was based on the Akaike information criterion and measures of robustness. In addition, the performance of several simplified methods, such as standardized uptake value (SUV), was assessed. Best fits were obtained using an irreversible compartment model with blood volume parameter. Parent fractions were 0.12 ± 0.4 after 20 min, necessitating individual metabolite corrections. Correspondence between venous and arterial parent fractions was low as determined by the intraclass correlation coefficient (0.61). Results for image-derived input functions that were obtained from volumes of interest in blood-pool structures distant from tissues of high (18)F-fluoromethylcholine uptake yielded good correlation to those for the blood-sampling input functions (R(2) = 0.83). SUV showed poor correlation to parameters derived from full quantitative kinetic analysis (R(2) < 0.34). In contrast, lesion activity concentration normalized to the integral of the blood activity concentration over time (SUVAUC) showed good correlation (R(2) = 0.92 for metabolite-corrected plasma; 0.65 for whole-blood activity concentrations). SUV cannot be used to quantify (18)F-fluoromethylcholine uptake. A clinical compromise could be SUVAUC derived from 2 consecutive static PET scans, one centered on a large blood-pool structure during 0-30 min after injection to obtain the blood activity concentrations and the other a whole-body scan at 30 min after injection to obtain lymph node activity concentrations. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Bidirectional light-scattering image processing method for high-concentration jet sprays

NASA Astrophysics Data System (ADS)

Shimizu, I.; Emori, Y.; Yang, W.-J.; Shimoda, M.; Suzuki, T.

1985-01-01

In order to study the distributions of droplet size and volume density in high-concentration jet sprays, a new technique is developed, which combines the forward and backward light scattering method and an image processing method. A pulsed ruby laser is used as the light source. The Mie scattering theory is applied to the results obtained from image processing on the scattering photographs. The time history is obtained for the droplet size and volume density distributions, and the method is demonstrated by diesel fuel sprays under various injecting conditions. The validity of the technique is verified by a good agreement in the injected fuel volume distributions obtained by the present method and by injection rate measurements.

Offline Solid-phase Extraction Large-volume Injection-Gas chromatography for the Analysis of Mineral Oil-saturated Hydrocarbons in Commercial Vegetable Oils.

PubMed

Liu, Lingling; Huang, Hua; Wu, Yanwen; Li, Bingning; Ouyang, Jie

2017-09-01

An offline solid-phase extraction (SPE) approach combined with a large-volume injection (LVI)-gas chromatography-flame ionization detector (LVI-GC-FID) is improved for routine analysis of mineral oil saturated hydrocarbons (MOSH) in vegetable oils. The key procedure of the method consists in using offline SPE columns for MOSH purification. The SPE column packed with 1% Ag-activated silica gel was used to separate MOSH from triglycerides and olefins in variety of vegetable oils. The eluent of MOSH fraction was only 3 mL and the concentration step was quick with little evaporation loss. The limit of quantification (LOQ) of the method was 2.5 mg/kg and the linearity ranged from 2 to 300 mg/kg. The accuracy was assessed by measuring the recoveries from spiked oil samples and was higher than 90%. Twenty-seven commercial vegetable oils were analyzed, and different levels of MOSH contamination were detected with the highest being 259.4 mg/kg. The results suggested that it is necessary to routinely detect mineral oil contamination in vegetable oils for food safety.

Signal Enhancement in HPLC/Micro-Coil NMR Using Automated Column Trapping

PubMed Central

Djukovic, Danijel; Liu, Shuhui; Henry, Ian; Tobias, Brian; Raftery, Daniel

2008-01-01

A new HPLC-NMR system is described that performs analytical separation, pre-concentration, and NMR spectroscopy in rapid succession. The central component of our method is the online pre-concentration sequence that improves the match between post-column analyte peak volume and the micro-coil NMR detection volume. Separated samples are collected on to a C18 guard column with a mobile phase composed of 90% D2O/10% acetonitrile-D3, and back-flashed to the NMR micro-coil probe with 90% acetonitrile-D3/10% D2O. In order to assess the performance of our unit, we separated a standard mixture of 1 mM ibuprofen, naproxen, and phenylbutazone using a commercially available C18 analytical column. The S/N measurements from the NMR acquisitions indicated that we achieved signal enhancement factors up to 10.4 (±1.2)-fold. Furthermore, we observed that pre-concentration factors increased as the injected amount of analyte decreased. The highest concentration enrichment of 14.7 (±2.2)-fold was attained injecting 100 μL solution of 0.2 mM (~4 μg) ibuprofen. PMID:17037915

Usefulness of an injectable anaesthetic protocol for semen collection through urethral catheterisation in domestic cats.

PubMed

Pisu, Maria Carmela; Ponzio, Patrizia; Rovella, Chiara; Baravalle, Michela; Veronesi, Maria Cristina

2017-10-01

Objectives Although less often requested in comparison with dogs, the collection of semen in cats can be necessary for artificial insemination, for semen evaluation in tom cats used for breeding and for semen storage. Urethral catheterisation after pharmacological induction with medetomidine has proved to be useful for the collection of semen in domestic cats. However, most of the previously used protocols require the administration of high doses of medetomidine that can increase the risk of side effects, especially on the cardiovascular system. In routine clinical practice, one safe and useful injectable anaesthetic protocol for short-term clinical investigations or surgery in cats involves premedication with low intramuscular doses of dexmedetomidine with methadone, followed by intravenous propofol bolus injection. We aimed to assess the usefulness of this injectable anaesthetic protocol for semen collection, via urethral catheterisation, in domestic cats. Methods The study was performed on 38 purebred, adult cats, during the breeding season, and semen was collected via urethral catheterisation using an injectable anaesthesia protocol with methadone (0.2 mg/kg) and dexmedetomidine (5 µg/kg) premedication, followed by induction with propofol. Results The anaesthetic protocol used in the present study allowed the collection of large-volume semen samples, characterised by good parameters and without side effects. Conclusions and relevance The results from the present study suggest that the injectable anaesthetic protocol using methadone and dexmedetomidine premedication, followed by induction with propofol, could be suitable and safe for the collection of a good-quality semen sample, via urethral catheterisation, in domestic cats. It can therefore be used as an alternative to previous medetomidine-based sedation protocols.

Transdiaphragmatic transport of tracer albumin from peritoneal to pleural liquid measured in rats.

PubMed

Lai-Fook, Stephen J; Houtz, Pamela K; Jones, Philip D

2005-12-01

In conscious Wistar-Kyoto rats, we studied the uptake of radioactive tracer (125)I-albumin into the pleural space and circulation after intraperitoneal (IP) injections with 1 or 5 ml of Ringer solution (3 g/dl albumin). Postmortem, we sampled pleural liquid, peritoneal liquid, and blood plasma 2-48 h after IP injection and measured their radioactivity and protein concentration. Tracer concentration was greater in pleural liquid than in plasma approximately 3 h after injection with both IP injection volumes. This behavior indicated transport of tracer through the diaphragm into the pleural space. A dynamic analysis of the tracer uptake with 5-ml IP injections showed that at least 50% of the total pleural flow was via the diaphragm. A similar estimate was derived from an analysis of total protein concentrations. Both estimates were based on restricted pleural capillary filtration and unrestricted transdiaphragmatic transport. The 5-ml IP injections did not change plasma protein concentration but increased pleural and peritoneal protein concentrations from control values by 22 and 30%, respectively. These changes were consistent with a small (approximately 8%) increase in capillary filtration and a small (approximately 20%) reduction in transdiaphragmatic flow from control values, consistent with the small (3%) decrease in hydration measured in diaphragm muscle. Thus the pleural uptake of tracer via the diaphragm with the IP injections occurred by the near-normal transport of liquid and protein.

The Influence of Injection Molding Parameter on Properties of Thermally Conductive Plastic

NASA Astrophysics Data System (ADS)

Hafizah Azis, N.; Zulafif Rahim, M.; Sa'ude, Nasuha; Rafai, N.; Yusof, M. S.; Tobi, ALM; Sharif, ZM; Rasidi Ibrahim, M.; Ismail, A. E.

2017-05-01

Thermally conductive plastic is the composite between metal-plastic material that is becoming popular because if it special characteristic. Injection moulding was regarded as the best process for mass manufacturing of the plastic composite due to its low production cost. The objective of this research is to find the best combination of the injection parameter setting and to find the most significant factor that effect the strength and thermal conductivity of the composite. Several parameter such as the volume percentage of copper powder, nozzle temperature and injection pressure of injection moulding machine were investigated. The analysis was done using Design Expert Software by implementing design of experiment method. From the analysis, the significant effects were determined and mathematical models of only significant effect were established. In order to ensure the validity of the model, confirmation run was done and percentage errors were calculated. It was found that the best combination parameter setting to maximize the value of tensile strength is volume percentage of copper powder of 3.00%, the nozzle temperature of 195°C and the injection pressure of 65%, and the best combination parameter settings to maximize the value of thermal conductivity is volume percentage of copper powder of 7.00%, the nozzle temperature of 195°C and the injection pressure of 65% as recommended..

The role of mineral heterogeneity on the hydrogeochemical response of two fractured reservoir rocks in contact with dissolved CO2

NASA Astrophysics Data System (ADS)

Garcia Rios, Maria; Luquot, Linda; Soler, Josep M.; Cama, Jordi

2017-04-01

In this study we compare the hydrogeochemical response of two fractured reservoir rocks (limestone composed of 100 wt.% calcite and sandstone composed of 66 wt.% calcite, 28 wt.% quartz and 6 wt.% microcline) in contact with CO2-rich sulfate solutions. Flow-through percolation experiments were performed using artificially fractured limestone and sandstone cores and injecting a CO2-rich sulfate solution under a constant volumetric flow rate (from 0.2 to 60 mL/h) at P = 150 bar and T = 60 °C. Measurements of the pressure difference between the inlet and the outlet of the samples and of the aqueous chemistry enabled the determination of fracture permeability changes and net reaction rates. Additionally, X-ray computed microtomography (XCMT) was used to characterize and localized changes in fracture volume induced by dissolution and precipitation reactions. In all reacted cores an increase in fracture permeability and in fracture volume was always produced even when gypsum precipitation happened. The presence of inert silicate grains in sandstone samples favored the occurrence of largely distributed dissolution structures in contrast to localized dissolution in limestone samples. This phenomenon promoted greater dissolution and smaller precipitation in sandstone than in limestone experiments. As a result, in sandstone reservoirs, the larger increase in fracture volume as well as the more extended distribution of the created volume would favor the CO2 storage capacity. The different distribution of created volume between limestone and sandstone experiments led to a different variation in fracture permeability. The progressive stepped permeability increase for sandstone would be preferred to the sharp permeability increase for limestone to minimize risks related to CO2 injection, favor capillary trapping and reduce energetic storage costs. 2D reactive transport simulations that reproduce the variation in aqueous chemistry and the fracture geometry (dissolution pattern) were performed using CrunchFlow. The calcite reactive surface area had to be diminished with respect to the geometric surface area in order to account for the transport control of the calcite dissolution reaction at pH < 5. The fitted reactive surface area was higher under faster flow conditions, reflecting a decrease in transport control and a more distributed reaction in sandstone compared to limestone.

Basics of Sterile Compounding: Particulate Matter.

PubMed

Akers, Michael J

2017-01-01

This article focuses on the requirements for particulate matter in sterile products. Topics include particles and quality, particulate matter standards (large- and small-volume injectables), development of the small-volume injectable test, electronic (light obscuration) and microscope testing, and special requirements for particulate matter in biopharmaceutical preparations. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Rapid Analysis of Carbohydrates in Bioprocess Samples: An Evaluation of the CarboPac SA10 for HPAE-PAD Analysis by Interlaboratory Comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sevcik, R. S.; Hyman, D. A.; Basumallich, L.

2013-01-01

A technique for carbohydrate analysis for bioprocess samples has been developed, providing reduced analysis time compared to current practice in the biofuels R&D community. The Thermofisher CarboPac SA10 anion-exchange column enables isocratic separation of monosaccharides, sucrose and cellobiose in approximately 7 minutes. Additionally, use of a low-volume (0.2 mL) injection valve in combination with a high-volume detection cell minimizes the extent of sample dilution required to bring sugar concentrations into the linear range of the pulsed amperometric detector (PAD). Three laboratories, representing academia, industry, and government, participated in an interlaboratory study which analyzed twenty-one opportunistic samples representing biomass pretreatment, enzymaticmore » saccharification, and fermentation samples. The technique's robustness, linearity, and interlaboratory reproducibility were evaluated and showed excellent-to-acceptable characteristics. Additionally, quantitation by the CarboPac SA10/PAD was compared with the current practice method utilizing a HPX-87P/RID. While these two methods showed good agreement a statistical comparison found significant quantitation difference between them, highlighting the difference between selective and universal detection modes.« less

Optimization of Composting for Explosives Contaminated Soil

DTIC Science & Technology

1991-09-30

undesirable and essentially economically unfeasible for the remediation of small sites due to the large expenditures required for the mobilization and...mm, 5 micron. * Detector: UV absorbance at 250 nm. " Mobile phase: 52% methanol/48% water. " Flow rate: 1.5 mL/min. * Injection volume: 50 1&L. The...and lOx calibration standards. 4-21 57SC/2hif 12/02/91 Samples were diluted with mobile phase as necessary to bring target analytes into the

Endoclips vs large or small-volume epinephrine in peptic ulcer recurrent bleeding

PubMed Central

Ljubicic, Neven; Budimir, Ivan; Biscanin, Alen; Nikolic, Marko; Supanc, Vladimir; Hrabar, Davor; Pavic, Tajana

2012-01-01

AIM: To compare the recurrent bleeding after endoscopic injection of different epinephrine volumes with hemoclips in patients with bleeding peptic ulcer. METHODS: Between January 2005 and December 2009, 150 patients with gastric or duodenal bleeding ulcer with major stigmata of hemorrhage and nonbleeding visible vessel in an ulcer bed (Forrest IIa) were included in the study. Patients were randomized to receive a small-volume epinephrine group (15 to 25 mL injection group; Group 1, n = 50), a large-volume epinephrine group (30 to 40 mL injection group; Group 2, n = 50) and a hemoclip group (Group 3, n = 50). The rate of recurrent bleeding, as the primary outcome, was compared between the groups of patients included in the study. Secondary outcomes compared between the groups were primary hemostasis rate, permanent hemostasis, need for emergency surgery, 30 d mortality, bleeding-related deaths, length of hospital stay and transfusion requirements. RESULTS: Initial hemostasis was obtained in all patients. The rate of early recurrent bleeding was 30% (15/50) in the small-volume epinephrine group (Group 1) and 16% (8/50) in the large-volume epinephrine group (Group 2) (P = 0.09). The rate of recurrent bleeding was 4% (2/50) in the hemoclip group (Group 3); the difference was statistically significant with regard to patients treated with either small-volume or large-volume epinephrine solution (P = 0.0005 and P = 0.045, respectively). Duration of hospital stay was significantly shorter among patients treated with hemoclips than among patients treated with epinephrine whereas there were no differences in transfusion requirement or even 30 d mortality between the groups. CONCLUSION: Endoclip is superior to both small and large volume injection of epinephrine in the prevention of recurrent bleeding in patients with peptic ulcer. PMID:22611315

Relative importance of column and adsorption parameters on the productivity in preparative liquid chromatography II: Investigation of separation systems with competitive Langmuir adsorption isotherms.

PubMed

Forssén, Patrik; Samuelsson, Jörgen; Fornstedt, Torgny

2014-06-20

In this study we investigated how the maximum productivity for commonly used, realistic separation system with a competitive Langmuir adsorption isotherm is affected by changes in column length, packing particle size, mobile phase viscosity, maximum allowed column pressure, column efficiency, sample concentration/solubility, selectivity, monolayer saturation capacity and retention factor of the first eluting compound. The study was performed by generating 1000 random separation systems whose optimal injection volume was determined, i.e., the injection volume that gives the largest achievable productivity. The relative changes in largest achievable productivity when one of the parameters above changes was then studied for each system and the productivity changes for all systems were presented as distributions. We found that it is almost always beneficial to use shorter columns with high pressure drops over the column and that the selectivity should be greater than 2. However, the sample concentration and column efficiency have very limited effect on the maximum productivity. The effect of packing particle size depends on the flow rate limiting factor. If the pumps maximum flow rate is the limiting factor use smaller packing, but if the pressure of the system is the limiting factor use larger packing up to about 40μm. Copyright © 2014 Elsevier B.V. All rights reserved.

Advanced transportation system studies technical area 2(TA-2): Heavy lift launch vehicle development. volume 1; Executive summary

NASA Technical Reports Server (NTRS)

McCurry, J.

1995-01-01

The purpose of the TA-2 contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. This document is part of the final report for the TA-2 contract. The final report consists of three volumes: Volume 1 is the Executive Summary, Volume 2 is Technical Results, and Volume 3 is Program Cost Estimates. The document-at-hand, Volume 1, provides a summary description of the technical activities that were performed over the entire contract duration, covering three distinct launch vehicle definition activities: heavy-lift (300,000 pounds injected mass to low Earth orbit) launch vehicles for the First Lunar Outpost (FLO), medium-lift (50,000-80,000 pounds injected mass to low Earth orbit) launch vehicles, and single-stage-to-orbit (SSTO) launch vehicles (25,000 pounds injected mass to a Space Station orbit).

Effect of injection rate on contrast-enhanced MR angiography image quality: Modulation transfer function analysis.

PubMed

Clark, Toshimasa J; Wilson, Gregory J; Maki, Jeffrey H

2017-07-01

Contrast-enhanced (CE)-MRA optimization involves interactions of sequence duration, bolus timing, contrast recirculation, and both R 1 relaxivity and R2*-related reduction of signal. Prior data suggest superior image quality with slower gadolinium injection rates than typically used. A computer-based model of CE-MRA was developed, with contrast injection, physiologic, and image acquisition parameters varied over a wide gamut. Gadolinium concentration was derived using Verhoeven's model with recirculation, R 1 and R2* calculated at each time point, and modulation transfer curves used to determine injection rates, resulting in optimal resolution and image contrast for renal and carotid artery CE-MRA. Validation was via a vessel stenosis phantom and example patients who underwent carotid CE-MRA with low effective injection rates. Optimal resolution for renal and carotid CE-MRA is achieved with injection rates between 0.5 to 0.9 mL/s and 0.2 to 0.3 mL/s, respectively, dependent on contrast volume. Optimal image contrast requires slightly faster injection rates. Expected signal-to-noise ratio varies with both contrast volume and cardiac output. Simulated vessel phantom and clinical carotid CE-MRA exams at an effective contrast injection rate of 0.4 to 0.5 mL/s demonstrate increased resolution. Optimal image resolution is achieved at intuitively low, effective injection rates (0.2-0.9 mL/s, dependent on imaging parameters and contrast injection volume). Magn Reson Med 78:357-369, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Injection Force of SoloSTAR® Compared with Other Disposable Insulin Pen Devices at Constant Volume Flow Rates

PubMed Central

van der Burg, Thomas

2011-01-01

Background Injection force is a particularly important practical aspect of therapy for patients with diabetes, especially those who have dexterity problems. This laboratory-based study compared the injection force of the SoloSTAR® insulin pen (SoloSTAR; sanofi-aventis) versus other available disposable pens at injection speeds based on the delivered volume of insulin released at the needle. Method Four different prefilled disposable pens were tested: SoloSTAR containing insulin glargine; FlexPen® and the Next Generation FlexPen® (NGFP) (Novo Nordisk), both containing insulin detemir; and KwikPen® containing insulin lispro (Eli Lilly). All pens were investigated using the maximum dispense volume for each pen type [80 units (U) for SoloSTAR; 60 U for the other pens], from the free needle tip dispensing into a beaker. Twenty pens of each type were fitted with the recommended needles and tested at two dose speeds (6 and 10 U/s); each pen was tested twice. Results Mean plateau injection force and maximum injection force were consistently lower with SoloSTAR compared with FlexPen, NGFP, and KwikPen at both injection speeds tested. An injection speed of 10 U/s was associated with higher injection force compared with 6 U/s for all the pens tested (p < .001). Conclusions SoloSTAR stands out because of its low injection force, even when compared with newer insulin pen devices such as the KwikPen and NGFP. This may enable patients, especially those with dexterity problems, to administer insulin more easily and improve management of their diabetes. PMID:21303637

Large-volume iodinated contrast medium extravasation: low frequency and good outcome after conservative management in a single-centre cohort of more than 67,000 patients.

PubMed

Ko, Chih-Hsiang; Tay, Shee Yen; Chang, Hsiu-Chin; Chan, Wing P

2018-06-12

Our aim was to retrospectively investigate the frequency and outcome of large-volume iodinated contrast medium (CM) extravasation in our institution and to compare our management protocol to current practice. Institutional review board approval was obtained, and informed consent was waived because the study was retrospective. From January 2008 to September 2016, radiological examinations with intravenous non-ionic iodinated CM administration were performed in 67,129 patients. Contrast medium extravasation events on CT scans and intravenous pyelograms but not on angiograms were included. All data were collected prospectively and stratified according to age, injection method (manual vs auto-injection), prevention of extravasation by various means (including intercom alarm), management of extravasation (routine application of silver sulfadiazine ointment, clobetasol propionate cream, and damp gauze at room temperature), etc. RESULTS: The incidence of large-volume CM extravasation was very low (0.04% [27/67,129] overall; 0.03% related to manual injection [age range, 59-92 years; mean, 75.4 years], and 0.045% related to auto-injection [age range, 36-86 years; mean, 65.8 years]). The CM extravasation volume in majority of patients was 20-40 ml in 5 of 9 patients (55.6%) in the manual injection group and 14 of 18 (77.8%) in the auto-injection group. Swelling and pain were the most common symptoms. No patient developed severe signs or needed surgical intervention. Results show a very low incidence of large-volume CM extravasation without severe complications or sequelae. The casual effect between our protocols and good outcome cannot be scrutinised thoroughly because the study lacks a control group and is retrospective. • The incidence of large-volume contrast medium extravasation (≥20 ml) was 0.04%. • No patient needed surgical intervention, and most recovered within 7 days. • Each element of our management protocol contributed to good outcome.

Rapid determination of tartaric acid in wines.

PubMed

Bastos, Sandra S T; Tafulo, Paula A R; Queirós, Raquel B; Matos, Cristina D; Sales, M Goreti F

2009-08-01

A flow-spectrophotometric method is proposed for the routine determination of tartaric acid in wines. The reaction between tartaric acid and vanadate in acetic media is carried out in flowing conditions and the subsequent colored complex is monitored at 475 nm. The stability of the complex and the corresponding formation constant are presented. The effect of wavelength and pH was evaluated by batch experiments. The selected conditions were transposed to a flow-injection analytical system. Optimization of several flow parameters such as reactor lengths, flow-rate and injection volume was carried out. Using optimized conditions, a linear behavior was observed up to 1000 microg mL(-1) tartaric acid, with a molar extinction coefficient of 450 L mg(-1) cm(-1) and +/- 1 % repeatability. Sample throughput was 25 samples per hour. The flow-spectrophotometric method was satisfactorily applied to the quantification of TA in wines from different sources. Its accuracy was confirmed by statistical comparison to the conventional Rebelein procedure and to a certified analytical method carried out in a routine laboratory.

Vitamin A determination in milk samples based on the luminol-periodate chemiluminescence system.

PubMed

Rishi, Lubna; Yaqoob, Mohammad; Waseem, Amir; Nabi, Abdul

2014-01-01

A simple and rapid flow injection (FI) method for the determination of retinyl acetate is reported based on its enhancing effect on the luminol-periodate chemiluminescence (CL) system in an alkaline medium. The detection limit (3s×blank) was 8.0×10⁻⁸ mol L⁻¹, with an injection throughput of 90 h⁻¹. The method allows linear increase of CL intensity over the retinyl acetate concentration range of 1.0-100×10⁻⁷ mol L⁻¹ (R²=0.9996) with relative standard deviations of 2.4% (n=10) for 5.0×10⁻⁷ mol L⁻¹. The key chemical and physical variables (reagent concentrations, flow rates, sample volume, and photomultiplier tube (PMT) voltage) were optimized and potential interferences were investigated. The method was successfully applied to human milk, fresh cow's milk and infant milk-based formulas and the results were in good agreement with the previously reported HPLC method. A brief discussion on the possible CL reaction mechanism is also presented.

Microfluidic direct injection method for analysis of urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) using molecularly imprinted polymers coupled on-line with LC-MS/MS.

PubMed

Shah, Kumar A; Peoples, Michael C; Halquist, Matthew S; Rutan, Sarah C; Karnes, H Thomas

2011-01-25

The work described in this paper involves development of a high-throughput on-line microfluidic sample extraction method using capillary micro-columns packed with MIP beads coupled with tandem mass spectrometry for the analysis of urinary NNAL. The method was optimized and matrix effects were evaluated and resolved. The method enabled low sample volume (200 μL) and rapid analysis of urinary NNAL by direct injection onto the microfluidic column packed with molecularly imprinted beads engineered to NNAL. The method was validated according to the FDA bioanalytical method validation guidance. The dynamic range extended from 20.0 to 2500.0 pg/mL with a percent relative error of ±5.9% and a run time of 7.00 min. The lower limit of quantitation was 20.0 pg/mL. The method was used for the analysis of NNAL and NNAL-Gluc concentrations in smokers' urine. Copyright © 2010 Elsevier B.V. All rights reserved.

Meso-Scale Wetting of Paper Towels

NASA Astrophysics Data System (ADS)

Abedsoltan, Hossein

In this study, a new experimental approach is proposed to investigate the absorption properties of some selected retail paper towels. The samples were selected from two important manufacturing processes, conventional wet pressing (CWP) considered value products, and through air drying (TAD) considered as high or premium products. The tested liquids were water, decane, dodecane, and tetradecane with the total volumes in micro-liter range. The method involves the point source injection of liquid with different volumetric flowrates, in the nano-liter per second range. The local site for injection was chosen arbitrarily on the sample surface. The absorption process was monitored and recorded as the liquid advances, with two distinct imaging system methods, infrared imaging and optical imaging. The microscopic images were analyzed to calculate the wetted regions during the absorption test, and the absorption diagrams were generated. These absorption diagrams were dissected to illustrate the absorption phenomenon, and the absorption properties of the samples. The local (regional) absorption rates were computed for Mardi Gras and Bounty Basic as the representative samples for CWP and TAD, respectively in order to be compared with the absorption capacity property of these two samples. Then, the absorption capacity property was chosen as an index factor to compare the absorption properties of all the tested paper towels.

A novel method for the rapid determination of polyethoxylated tallow amine surfactants in water and sediment using large volume injection with high performance liquid chromatography and tandem mass spectrometry.

PubMed

Ross, Andrew R S; Liao, Xiangjun

2015-08-19

Polyethoxylated tallow amine (POEA) surfactants have been used in many glyphosate-based herbicide formulations for agricultural, industrial and residential weed control. The potential for release of these compounds into the environment is of increasing concern due to their toxicity towards aquatic organisms. Current methods for analysis of POEA surfactants require significant time and effort to achieve limits of quantification that are often higher than the concentrations at which biological effects have been observed (as low as 2 ng mL(-1)). We have developed a rapid and robust method for quantifying the POEA surfactant mixture MON 0818 at biologically relevant concentrations in fresh water, sea water and lake sediment using reversed phase high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Water samples preserved by 1:1 v/v dilution with methanol are analyzed directly following centrifugation. Sediment samples undergo accelerated solvent extraction in aqueous methanol prior to analysis. Large volume (100 μL) sample injection and multiple reaction monitoring of a subset of the most abundant POEA homologs provide limits of quantification of 0.5 and 2.9 ng mL(-1) for MON 0818 in fresh water and sea water, respectively, and 2.5 ng g(-1) for total MON 0818 in lake sediment. Average recoveries of 93 and 75% were achieved for samples of water and sediment, respectively spiked with known amounts of MON 0818. Precision and accuracy for the analysis of water and sediment samples were within 10 and 16%, respectively based upon replicate analyses of calibration standards and representative samples. Results demonstrate the utility of the method for quantifying undegraded MON 0818 in water and sediment, although a more comprehensive method may be needed to identify and determine other POEA mixtures and degradation profiles that might occur in the environment. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Correlation of Hydraulic Fracturing Induced Seismicity with Operation Parameters of Shale Gas Extraction: Two Case Studies in Western Canada

NASA Astrophysics Data System (ADS)

Farahbod, A. M.; Kao, H.; Cassidy, J. F.; Snyder, D. B.; Cairns, S.; Walker, D.

2015-12-01

Northeast British Columbia, specifically the Horn River Basin (HRB) and Montney Trend, are among the largest shale gas production regions in western Canada. In contrast, there has been no large-scale hydraulic fracturing (HF) operation in the Northwest Territories in the Norman Wells region of the central Mackenzie valley. In this study, we investigate the effect of injection pressure, operation duration and injected volume on the observed seismicity in the HRB and Norman Wells regions and compare our observations with the pre-HF records. In the HRB, we apply the single-station location and waveform correlation methods to establish a homogenous earthquake catalog (2006/12-2011/12). In the Northwest Territories, we combine data from a local seismograph network of 4 stations plus a dense array of 7 stations located from 1 km to 50 km from the operation wells to locate earthquakes (2013/09-2014/07). In the HRB, the initial effect of an increased injected volume is an increase in earthquake frequency but not magnitude. Local earthquakes gradually become larger in magnitude as the scale of HF in the region expands. While the injection pressure during HF operations has been regulated at a relatively constant level, the massive increase of injection volume in 2010 and 2011 coincides with a series of ML>3 events. Relatively large seismic moment release (>1014 N m) occurred only when the monthly injected volume exceeded ~150,000 m3. In addition, we observe variable time lags, from days to up to 4 months between intense HF and the occurrence of a significant local earthquake. On the other hand, in the Norman Wells region, two small-scale HF were performed in 2014 with a total injected volume of ~ 14000 m3. We observed an increase in the number of micro-earthquakes (M < 2.0) during the HF period without a clear change in the overall seismic pattern. From these two observations, we conclude that HF operations do not necessarily result in an increase in the occurrence rate of larger earthquakes. A clear change in background seismicity pattern towards more frequent occurrence and/or greater magnitudes occurred only when the monthly total injected volume became significantly higher. The hydrologic properties of the source formations and local geologic conditions might also play important roles in induced seismogenesis.

Observational study of changes in epidural pressure and elastance during epidural blood patch in obstetric patients.

PubMed

Pratt, S D; Kaczka, D W; Hess, P E

2014-05-01

During an epidural blood patch, we inject blood until the patient describes mild back pressure, often leading to injection of more than 20 mL of blood. We undertook this study to measure the epidural pressures generated during an epidural blood patch and to identify the impact of volume on epidural elastance in obstetric patients. This study was performed in postpartum patients who presented for an epidural blood patch with symptoms consistent with a postdural puncture headache. After identification of the epidural space using loss of resistance to air or saline, we measured static epidural pressure after each 5-mL injection of blood. Models were then fitted to the data and the epidural elastance and compliance calculated. Eighteen blood patches were performed on 17 patients. The mean final volume injected was 18.9±7.8 mL [range 6-38 mL]. The mean final pressure generated was 13.1±13.4 mmHg [range 2-56 mmHg]. A curvilinear relationship existed between volume injected and pressure, which was described by two models: (1) pressure=0.0254×(mL injected)(2)+0.0297 mL, or (2) pressure=0.0679×mL(1.742). The value for r2 was approximately 0.57 for both models. We found no correlation between the final pressure generated and the success of the epidural blood patch. We found a curvilinear relationship between the volume of blood injected during an epidural blood patch and the pressure generated in the epidural space. However, there was a large variation in both the volume of blood and the epidural pressure generated. The clinical importance of this finding is not known. A larger study would be required to demonstrate whether pressure is a predictor of success. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of OK-432 Injection Therapy as Possible Primary Treatment of Intraoral Ranula.

PubMed

Kono, Michihide; Satomi, Takafumi; Abukawa, Harutsugi; Hasegawa, On; Watanabe, Masato; Chikazu, Daichi

2017-02-01

A ranula is a pseudocyst caused by mucous extravasation from the sublingual gland. Recently, a sclerosing agent, OK-432 (picibanil), has been reported to be highly effective for treating lymphangioma and cervical cystic lesions. The present study assessed the effectiveness of OK-432 injection therapy for intraoral ranula to clarify whether it can be used as the primary treatment. The present study was a retrospective clinical study of patients with intraoral ranula who received OK-432 injection therapy from 2005 to 2015. The ranula size was measured on computed tomography or magnetic resonance imaging studies. We dissolved 1 Klinische Einheit (KE) unit of OK-432 powder in normal saline equal to the aspiration volume. The primary endpoint was the treatment results. The secondary endpoints were the relation between the treatment results and the lesion length and aspiration volume. A total of 23 patients received OK-432 injection therapy for an intraoral ranula. The mean lesion size was 19.96 mm. The mean aspiration volume was 2.14 mL. The number of injections was 1 to 4 (mean 1.70). The treatment results were complete regression (CR) in 18 (78.2%), partial regression (PR) in 3 (13.0%), and no response (NR) in 2 (8%) patients after the last injection. The overall efficacy rate was 91.2% (21 of 23). No serious complications were observed. The lesion length and aspiration volume of the CR group was 17.38 mm and 1.40 mL, respectively. The lesion length and aspiration volume of the PR/NR group was 29.20 mm and 4.80 mL, respectively. The PR/NR group lesions were significantly larger than the CR group lesions. OK-432 injection therapy for intraoral ranula is safe and effective compared with other surgical therapies. This therapy could potentially become a primary treatment of intraoral ranula. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Legionnaires' Disease Bacteria in power plant cooling systems: downtime report. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyndall, R.L.; Solomon, J.A.; Christensen, S.W.

1985-04-01

Legionnaires' Disease Bacteria (Legionella) are a normal part of the aquatic community that, when aerosolized, can be pathogenic to man. The downtime study was designed to determine the degree to which Legionella populations are aerosolized during cleaning and maintenance operations in a closed-cycle steam-electric power plant. Both high-volume and impinger air samples were collected prior to and during downtime operations. Emphasis was placed on sampling inside or adjacent to water boxes, condensers, and cooling towers. Control air samples were taken upwind from the plant site. Water and sludge samples were also collected at various locations. In the laboratory, the concentrationsmore » of Groups A, B, and C Legionella were determined using the direct fluorescent antibody method. All positive air samples, and other selected air samples, were injected into guinea pigs to detect infectious Legionella. Legionella could be detected in only 12 of the 126 air samples collected. These were predominantly Group A Legionella (L. pneumophila, serogroups 1 to 6). All 12 positive samples had been collected in the vicinity of water boxes, condensers, detention ponds, and cooling towers during downtime operations where aerosolization of Legionella populations would be expected. None of the air samples yielded infectious Legionella when injected into guinea pigs. Detection of Legionella in air samples taken during downtime was significantly more likely than detection during normal operating conditions (p <0.01). 13 refs., 4 figs., 10 tabs.« less

Grounding electrode and method of reducing the electrical resistance of soils

DOEpatents

Koehmstedt, Paul L.

1980-01-01

A first solution of an electrolyte is injected underground into a volume of soil having negative surface charges on its particles. A cationic surfactant suspended in this solution neutralizes these surface charges of the soil particles within the volume. Following the first solution, a cationic asphalt emulsion suspended in a second solution is injected into the volume. The asphalt emulsion diffuses through the volume and electrostatically bonds with additional soil surrounding the volume such that an electrically conductive water repellant shell enclosing the volume is formed. This shell prevents the leaching of electrolyte from the volume into the additional soil. The second solution also contains a dissolved deliquescent salt which draws water into the volume prior to the formation of the shell. When electrically connected to an electrical installation such as a power line tower, the volume constitutes a grounding electrode for the tower.

Thickness and Closure Kinetics of the Suprachoroidal Space Following Microneedle Injection of Liquid Formulations

PubMed Central

Chiang, Bryce; Venugopal, Nitin; Grossniklaus, Hans E.; Jung, Jae Hwan; Edelhauser, Henry F.; Prausnitz, Mark R.

2017-01-01

Purpose To determine the effect of injection volume and formulation of a microneedle injection into the suprachoroidal space (SCS) on SCS thickness and closure kinetics. Methods Microneedle injections containing 25 to 150 μL Hanks' balanced salt solution (HBSS) were performed in the rabbit SCS ex vivo. Distribution of SCS thickness was measured by ultrasonography and three-dimensional (3D) cryo-reconstruction. Microneedle injections were performed in the rabbit SCS in vivo using HBSS, Discovisc, and 1% to 5% carboxymethyl cellulose (CMC) in HBSS. Ultrasonography was used to track SCS thickness over time. Results Increasing HBSS injection volume increased the area of expanded SCS, but did not increase SCS thickness ex vivo. With SCS injections in vivo, the SCS initially expanded to thicknesses of 0.43 ± 0.06 mm with HBSS, 1.5 ± 0.4 mm with Discovisc, and 0.69 to 2.1 mm with 1% to 5% CMC. After injection with HBSS, Discovisc, and 1% CMC solution, the SCS collapsed to baseline with time constants of 19 minutes, 6 hours, and 2.4 days, respectively. In contrast, injections with 3% to 5% CMC solution resulted in SCS expansion to 2.3 to 2.8 mm over the course of 2.8 to 9.1 hours, after which the SCS collapsed to baseline with time constants of 4.5 to 9.2 days. Conclusions With low-viscosity formulations, SCS expands to a thickness that remains roughly constant, independent of the volume of fluid injected. Increasing injection fluid viscosity significantly increased SCS thickness. Expansion of the SCS is hypothesized to be controlled by a balance between the viscous forces of the liquid formulation and the resistive biomechanical forces of the tissue. PMID:28125842

Thickness and Closure Kinetics of the Suprachoroidal Space Following Microneedle Injection of Liquid Formulations.

PubMed

Chiang, Bryce; Venugopal, Nitin; Grossniklaus, Hans E; Jung, Jae Hwan; Edelhauser, Henry F; Prausnitz, Mark R

2017-01-01

To determine the effect of injection volume and formulation of a microneedle injection into the suprachoroidal space (SCS) on SCS thickness and closure kinetics. Microneedle injections containing 25 to 150 μL Hanks' balanced salt solution (HBSS) were performed in the rabbit SCS ex vivo. Distribution of SCS thickness was measured by ultrasonography and three-dimensional (3D) cryo-reconstruction. Microneedle injections were performed in the rabbit SCS in vivo using HBSS, Discovisc, and 1% to 5% carboxymethyl cellulose (CMC) in HBSS. Ultrasonography was used to track SCS thickness over time. Increasing HBSS injection volume increased the area of expanded SCS, but did not increase SCS thickness ex vivo. With SCS injections in vivo, the SCS initially expanded to thicknesses of 0.43 ± 0.06 mm with HBSS, 1.5 ± 0.4 mm with Discovisc, and 0.69 to 2.1 mm with 1% to 5% CMC. After injection with HBSS, Discovisc, and 1% CMC solution, the SCS collapsed to baseline with time constants of 19 minutes, 6 hours, and 2.4 days, respectively. In contrast, injections with 3% to 5% CMC solution resulted in SCS expansion to 2.3 to 2.8 mm over the course of 2.8 to 9.1 hours, after which the SCS collapsed to baseline with time constants of 4.5 to 9.2 days. With low-viscosity formulations, SCS expands to a thickness that remains roughly constant, independent of the volume of fluid injected. Increasing injection fluid viscosity significantly increased SCS thickness. Expansion of the SCS is hypothesized to be controlled by a balance between the viscous forces of the liquid formulation and the resistive biomechanical forces of the tissue.

Analysis of dissolved organic carbon concentration and 13C isotopic signature by TOC-IRMS - assessment of analytical performance

NASA Astrophysics Data System (ADS)

Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Kalbitz, Karsten

2013-04-01

Stable carbon isotopes provide a powerful tool to assess carbon pools and their dynamics. Dissolved organic carbon (DOC) has been recognized to play an important role in ecosystem functioning and carbon cycling and has therefore gained increased research interest. However, direct measurement of 13C isotopic signature of carbon in the dissolved phase is technically challenging particularly using high temperature combustion. Until recently, mainly custom-made systems existed which were modified for coupling of TOC instruments with IRMS for simultaneous assessment of C content and isotopic signature. The variety of coupled systems showed differences in their analytical performances. For analysis of DOC high temperature combustion is recognized as best performing method, owing to its high efficiency of conversion to CO2 also for highly refractory components (e.g. humic, fulvic acids) present in DOC and soil extracts. Therefore, we tested high temperature combustion TOC coupled to IRMS (developed by Elementar Group) for bulk measurements of DOC concentration and 13C signature. The instruments are coupled via an Interface to exchange the carrier gas from O2 to He and to concentrate the derived CO2 for the isotope measurement. Analytical performance of the system was assessed for a variety of organic compounds characterized by different stability and complexity, including humic acid and DOM. We tested injection volumes between 0.2-3 ml, thereby enabling measurement of broad concentration ranges. With an injection volume of 0.5 ml (n=3, preceded by 1 discarded injection), DOC and 13C signatures for concentrations between 5-150 mg C/L were analyzed with high precision (standard deviation (SD) predominantly <0.1‰), good accuracy and linearity (overall SD <0.9‰). For the same settings, slightly higher variation in precision was observed among the lower concentration range and depending upon specific system conditions. Differences in 13C signatures of about 50‰ among samples did not affect the precision of the analysis of natural abundance and labeled samples. Natural DOM, derived from different soils and assessed at various concentrations, was measured with similar good analytical performance, and also tested for the effect of freezing and re-dissolving. We found good performance of TOC-IRMS in comparison with other systems capable of determining C concentration and isotopic signatures. We recognize the advantages of this system providing: - High sample throughput, short measurement time (15 minutes), flexible sample volume - Easy maintenance, handling, rapid sample preparation (no pretreatment) This preliminary assessment highlights wide-ranging opportunities for further research on concentrations and isotopic signatures by TOC-IRMS to elucidate the role of dissolved carbon in terrestrial and aquatic systems.

Orbital volume augmentation using expandable hydrogel implants in acquired anophthalmia and phthisis bulbi.

PubMed

Kim, Esther Lee; Bernardino, Carlo Rob; Levin, Flora

2016-01-01

The purpose of this study is to describe our experience using expandable spherical hydrogel implants and injectable hydrogel pellets for orbital volume augmentation in cases of post-enucleation socket syndrome after acquired anophthalmia or phthisis bulbi. We retrospectively reviewed the clinical records of all adult patients who received an expandable hydrogel implant for orbital volume loss following enucleation or phthisis bulbi at the Emory Eye Center between 2004 and January 2007 and the Yale Eye Center between 2009 and 2011. The study included 9 women and 5 men with a mean age of 51.2 years old (range 35-76 years old). Follow-up spanned 6 to 71 months (median of 18.5 months). Four patients received spherical hydrogel implants and 10 patients received hydrogel pellet injections. On average, nine pellets (range 5-16) were placed in each patient over an average of 1.7 injections (range 1-3). Most commonly, five pellets were injected per session, as was the case for 13 of the 17 treatment sessions. Post-operative complications included 2 cases of pellet migration, one subcutaneously and one anteriorly due to insufficiently posterior implant placement, and 1 hospital admission for pain after injection of 10 pellets in one visit. All patients experienced an overall subjective improvement in cosmesis. Self-expandable hydrogel implants appear to offer several advantages over other existing options for orbital volume augmentation, as they are easy to place, generally well-tolerated, volume-titratable, and to the extent that our follow-up shows, may be a safe and durable means of treating orbital volume loss in patients with acquired anophthalmia and phthisis bulbi.

Multiresidue analysis of acidic and polar organic contaminants in water samples by stir-bar sorptive extraction-liquid desorption-gas chromatography-mass spectrometry.

PubMed

Quintana, José Benito; Rodil, Rosario; Muniategui-Lorenzo, Soledad; López-Mahía, Purificación; Prada-Rodríguez, Darío

2007-12-07

The feasibility of stir-bar sorptive extraction (SBSE) followed by liquid desorption in combination with large volume injection (LVI)-in port silylation and gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of a broad range of 46 acidic and polar organic pollutants in water samples has been evaluated. The target analytes included phenols (nitrophenols, chlorophenols, bromophenols and alkylphenols), acidic herbicides (phenoxy acids and dicamba) and several pharmaceuticals. Experimental variables affecting derivatisation yield and peak shape as a function of different experimental PTV parameters [initial injection time, pressure and temperature and the ratio solvent volume/N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) volume] were first optimised by an experimental design approach. Subsequently, SBSE conditions, such as pH, ionic strength, agitation speed and extraction time were investigated. After optimisation, the method failed only for the extraction of most polar phenols and some pharmaceuticals, being suitable for the determination of 37 (out of 46) pollutants, with detection limits for these analytes ranging between 1 and 800 ng/L and being lower than 25 ng/L in most cases. Finally, the developed method was validated and applied to the determination of target analytes in various aqueous environmental matrices, including ground, river and wastewater. Acceptable accuracy (70-130%) and precision values (<20%) were obtained for most analytes independently of the matrix, with the exception of some alkylphenols, where an isotopically labelled internal standard would be required in order to correct for matrix effects. Among the drawbacks of the method, carryover was identified as the main problem even though the Twisters were cleaned repeatedly.

Solid surface wetting and the deployment of drops in microgravity

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Depew, J.

1994-01-01

The complete or partial deployment of liquid samples in low gravity is primarily influenced by the interfacial properties of the specific liquid and solid materials used because the overwhelming bias of the Earth gravitational acceleration is removed. This study addresses the engineering aspects of injecting and deploying drops of prescribed volume into an acoustic positioning chamber in microgravity. The specific problems of interest are the design, testing, and implementation of injector tips to be used in a simultaneously retracting dual-injector system in the Drop Physics Module microgravity experiment facility. Prior to release, the liquid to be deployed must be retained within a restricted area at the very end of the injectors under dynamic stimuli from the continuous injection flow as well as from the stepped motion of the injectors. The final released drop must have a well determined volume and negligible residual linear or angular momentum. The outcome of Earth-based short-duration low gravity experiments had been the selection of two types of injector tips which were flown as back-up parts. They were successfully utilized during the USML-1 Spacelab mission as the primary tips. The combination of a larger contact surface, liquid pinning with a sharp edge, and selective coating of strategic tip surfaces with a non-wetting compound has allowed a significant increase in the success rate of deployment of simple and compound drops of aqueous solutions of glycerol and silicone oil. The diameter of the samples studied in the Drop Physics Module range between 0.3 and 2.7 cm. The tests conducted on-orbit with a manually operated small device have allowed the calibration of the volume deployed for a few drop sizes. The design for improved tips to be used during the next USML flight is based on these results.

Solid Surface Wetting and the Deployment of Drops in Microgravity

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Depew, J.

1994-01-01

The complete or partial deployment of liquid samples in low gravity is primarily influenced by the interfacial properties of the specific liquid and solid materials used because the overwhelming bias of the Earth gravitational acceleration is removed. This study addresses the engineering aspects of injecting and deploying drops of prescribed volume into an acoustic positioning chamber in microgravity. The specific problems of interest are the design, testing, and implementation of injector tips to be used in a simuttaneously retracting dual-injector system used in the Drop Physics Module microgravity experiment facility. Prior to release, the liquid to be deployed must be retained within a restricted area at the very end of the injectors even under dynamic stimuli due to continuous injection flow as well as to the stepped motion of the injectors, and the final released drop must have a well determined volume as well as negligible residual linear or angular momentum from the deployment process. The outcome of Earthbased short-duration low gravity experiments had been the selection of two types of injector tips which were flown as back-up parts and were successfully utilized during the USML-1 Spacelab mission. The combination of a larger contact surface, liquid pinning with a sharp edge, and selective coating of strategic tip surfaces with a non-wetting compound has allowed a significant increase in the success rate of deployment of simple and compound drops of aqueous solutions of glycerol and silicone oil. The diameter of the samples studied in the Drop Physics Module ranged between 0.3 and 2.7 cm. The tests conducted onsrbit with a manually operated small device have allowed the calibration of the volume deployed for a few drop sizes. The design for improved tips to be used during the next USML flight is based on these results.

Application of large volume injection GC-MS to analysis of organic compounds in the extracts and leachates of municipal solid waste incineration fly ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korenkova, Eva; Matisova, Eva; Slobodnik, Jaroslav

2006-07-01

Organic solvent and water extracts of fly ash from a Milan (Italy) municipal solid waste incinerator (MSWI) were analyzed by large volume injection-gas chromatography-mass spectrometry (LVI-GC-MS) with programmable temperature vaporizer (PTV). Using injection volumes of 10-100 {mu}l, typically over a hundred compounds were detected in organic solvent extracts and ca. 35% of them could be tentatively identified from their electron impact ionization mass spectra. A protocol for the determination of the maximum amount of a potential environmental pollutant available for leaching (availability test) was developed for four selected target compounds: pentachlorobenzene (PeCB), hexachlorobenzene (HxCB), o-terphenyl (o-TPH) and m-terphenyl (m-TPH). Keymore » parameters, extraction time and liquid-to-solid ratio (L/S), were studied in more detail. Recoveries of PeCB, HxCB and o-TPH spiked into the fly ash samples at two concentration levels ranged from 38% to 53% for freshly spiked and from 14% to 40% for 40-day aged fly ash. Recoveries of m-TPH were 8% to 11% from freshly spiked and less than 3% from aged spiked fly ash. The native amounts in Milan MSWI fly ash, determined in an interlaboratory exercise using the developed protocol, were 31 ng/g PeCB, 34 ng/g HxCB, 72 ng/g o-TPH and 4.4 ng/g m-TPH. A separate methodology was developed for the determination of compounds extracted from fly ash by water (leaching test). Following 8-h sonication at L/S 20, the leached amounts of PeCB, HxCB and o-TPH were 1.1, 3.1 and 6.0 ng/g fly ash, respectively.« less

Design and performance of a new continuous-flow sample-introduction system for flame infrared-emission spectrometry: Applications in process analysis, flow injection analysis, and ion-exchange high-performance liquid chromatography.

PubMed

Lam, C K; Zhang, Y; Busch, M A; Busch, K W

1993-06-01

A new sample introduction system for the analysis of continuously flowing liquid streams by flame infrared-emission (FIRE) spectrometry has been developed. The system uses a specially designed purge cell to strip dissolved CO(2) from solution into a hydrogen gas stream that serves as the fuel for a hydrogen/air flame. Vibrationally excited CO(2) molecules present in the flame are monitored with a simple infrared filter (4.4 mum) photometer. The new system can be used to introduce analytes as a continuous liquid stream (process analysis mode) or on a discrete basis by sample injection (flow injection analysis mode). The key to the success of the method is the new purge-cell design. The small internal volume of the cell minimizes problems associated with purge-cell clean-out and produces sharp, reproducible signals. Spent analytical solution is continuously drained from the cell, making cell disconnection and cleaning between samples unnecessary. Under the conditions employed in this study, samples could be analyzed at a maximum rate of approximately 60/h. The new sample introduction system was successfully tested in both a process analysis- and a flow injection analysis mode for the determination of total inorganic carbon in Waco tap water. For the first time, flame infrared-emission spectrometry was successfully extended to non-volatile organic compounds by using chemical pretreatment with peroxydisulfate in the presence of silver ion to convert the analytes into dissolved carbon dioxide, prior to purging and detection by the FIRE radiometer. A test of the peroxydisulfate/Ag(+) reaction using six organic acids and five sugars indicated that all 11 compounds were oxidized to nearly the same extent. Finally, the new sample introduction system was used in conjunction with a simple filter FIRE radiometer as a detection system in ion-exchange high-performance liquid chromatography. Ion-exchange chromatograms are shown for two aqueous mixtures, one containing six organic acids and the second containing six mono-, di-, and trisaccharides.

Highly efficient and ultra-small volume separation by pressure-driven liquid chromatography in extended nanochannels.

PubMed

Ishibashi, Ryo; Mawatari, Kazuma; Kitamori, Takehiko

2012-04-23

The rapidly developing interest in nanofluidic analysis, which is used to examine liquids ranging in amounts from the attoliter to the femtoliter scale, correlates with the recent interest in decreased sample amounts, such as in the field of single-cell analysis. For general nanofluidic analysis, the fact that a pressure-driven flow does not limit the choice of solvents (aqueous or organic) is important. This study shows the first pressure-driven liquid chromatography technique that enables separation of atto- to femtoliter sample volumes, with a high separation efficiency within a few seconds. The apparent diffusion coefficient measurement of the unretentive sample suggests that there is no increase in the viscosity of toluene in the extended nanospace, unlike in aqueous solvents. Evaluation of the normal phase separation, therefore, should involve only the examination of the effect of the small size of the extended nanospace. Compared to a conventionally packed high-performance liquid chromatography column, the separation here results in a faster separation (4 s) by 2 orders of magnitude, a smaller injection volume (10(0) fL) by 9 orders, and a higher separation efficiency (440,000 plates/m) by 1 order. Moreover, the separation behavior agrees with the theory showing that this high efficiency was due to the small and controlled size of the separation channel, where the diffusion through the channel depth direction is fast enough to be neglected. Our chip-based platform should allow direct and real-time analysis or screening of ultralow volume of sample. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of the acute and chronic safety of the biosense injection catheter system in porcine hearts.

PubMed

Kornowski, R; Fuchs, S; Tio, F O; Pierre, A; Epstein, S E; Leon, M B

1999-12-01

Direct myocardial injection of therapeutic agents has been explored as a new method for myocardial revascularization. The integration of a 3D electromechanical mapping catheter with a retractable injection needle should allow for intramyocardial injection to identified sites, obviating the need for open heart surgery. This study assessed the procedural safety and performance characteristics of a novel guided catheter-based transendocardial injection system. The electromagnetic guidance system was coupled with a retrievable 27G needle for left ventricular endocardial injection. Using this system, we injected, transendocardially, methylene-blue (MB) dye tracer at a volume of 0.1 or 0.2 ml per injection in eight normal pigs. Animals were sacrificed acutely, at 1, 3, and 7 days (two animal in each time). Three animals served as controls. The injections were followed by coronary angiography and echocardiogram to assess possible ventricular or coronary perforation and wall motion abnormalities. CK-MB levels were measured up to 24 hr following the procedure. The animals were sacrificed at the assigned time for gross and histopathology evaluation. A total of 101 injections were made in all regions of the heart except the apex and the mitral valve. No animal died as a result of the mapping or injection procedures. Vital signs did not change relative to baseline after the mapping and injection procedures. CK-MB values did not increase over time and there was no evidence of sustained arrhythmia or hemodynamic compromise. There was no evidence of left ventricular or coronary perforation, global or regional wall motion abnormalities, or hemopericardium. On histologic evaluation, the estimated volume of tissue staining was greater than the volume of the injected MB dye due to dispersion of the injectate in the interstitial and intracellular fluid compartments. It is concluded that using this magnetic guidance catheter-based navigational system, it is feasible and safe to perform the transendocardial injection procedure. Thus, if it is determined that direct intramyocardial injection of drugs is a valid therapeutic strategy, this approach offers a clear advantage over surgically based transepicardial injection procedures. Cathet. Cardiovasc. Intervent. 48:447-453, 1999. Copyright 1999 Wiley-Liss, Inc.

The effects of a single intravenous injection of novel activin A/BMP-2 (AB204) on toxicity and the respiratory and central nervous systems

PubMed Central

Yoon, Byung-Hak; Lee, Jae Hyup; Na, Kyuheum; Ahn, Chihoon; Cho, Jongho; Ahn, Hyun Chan; Choi, Jungyoun; Oh, Hyosun; Kim, Byong Moon; Choe, Senyon

2018-01-01

The purpose of this study was to determine the effects of a single intravenous injection of a novel osteoinductive material, activin A/BMP-2 (AB204), to rodents on toxicity and their respiratory functions and central nervous system (CNS). A single intravenous injection of AB204 was given to Sprague–Dawley (SD) rats in doses of 0, 0.625, 2.5 and 10 mg/kg to observe the mortality rate, the general symptoms for 14 days. The experimental groups were also given 0.2, 0.4 and 0.8 mg/kg of AB204, respectively, and the respiration rate, the tidal volume and the minute volume were measured for 240 min. The experimental groups of imprinting control region (ICR) mice were given a single intravenous injection of 0.2, 0.4 and 0.8 mg/kg of AB204, respectively. Their body temperature was taken and general behaviors were observed to evaluate the effect of AB204 on the CNS for 240 min. The study on toxicity of a single intravenous injection found no death or abnormal symptoms, abnormal findings from autopsy, or abnormal body weight gain or loss in all the experimental groups. No abnormal variation associated with the test substance was observed in the respiration rate, the tidal volume, the minute volume, body temperature or the general behaviors. On the basis of these results, the approximate lethal dose of AB204 for a single intravenous injection exceeds 10 mg/kg for SD rats and a single intravenous injection of ≤0.8 mg/kg AB204 has no effect on their respiratory system for SD rat and no effect on their CNS for ICR mice. PMID:26446865

The effects of a single intravenous injection of novel activin A/BMP-2 (AB204) on toxicity and the respiratory and central nervous systems.

PubMed

Yoon, Byung-Hak; Lee, Jae Hyup; Na, Kyuheum; Ahn, Chihoon; Cho, Jongho; Ahn, Hyun Chan; Choi, Jungyoun; Oh, Hyosun; Kim, Byong Moon; Choe, Senyon

2016-01-01

The purpose of this study was to determine the effects of a single intravenous injection of a novel osteoinductive material, activin A/BMP-2 (AB204), to rodents on toxicity and their respiratory functions and central nervous system (CNS). A single intravenous injection of AB204 was given to Sprague-Dawley (SD) rats in doses of 0, 0.625, 2.5 and 10 mg/kg to observe the mortality rate, the general symptoms for 14 days. The experimental groups were also given 0.2, 0.4 and 0.8 mg/kg of AB204, respectively, and the respiration rate, the tidal volume and the minute volume were measured for 240 min. The experimental groups of imprinting control region (ICR) mice were given a single intravenous injection of 0.2, 0.4 and 0.8 mg/kg of AB204, respectively. Their body temperature was taken and general behaviors were observed to evaluate the effect of AB204 on the CNS for 240 min. The study on toxicity of a single intravenous injection found no death or abnormal symptoms, abnormal findings from autopsy, or abnormal body weight gain or loss in all the experimental groups. No abnormal variation associated with the test substance was observed in the respiration rate, the tidal volume, the minute volume, body temperature or the general behaviors. On the basis of these results, the approximate lethal dose of AB204 for a single intravenous injection exceeds 10 mg/kg for SD rats and a single intravenous injection of ≤0.8 mg/kg AB204 has no effect on their respiratory system for SD rat and no effect on their CNS for ICR mice.

Intratympanic Iodine Contrast Injection Diffuses Across the Round Window Membrane Allowing for Perilymphatic CT Volume Acquisition Imaging

PubMed Central

Abt, Nicholas B.; Lehar, Mohamed; Guajardo, Carolina Trevino; Penninger, Richard T.; Ward, Bryan K.; Pearl, Monica S.; Carey, John P.

2016-01-01

Hypothesis Whether the RWM is permeable to iodine-based contrast agents (IBCA) is unknown; therefore, our goal was to determine if IBCAs could diffuse through the RWM using CT volume acquisition imaging. Introduction Imaging of hydrops in the living human ear has attracted recent interest. Intratympanic (IT) injection has shown gadolinium's ability to diffuse through the round window membrane (RWM), enhancing the perilymphatic space. Methods Four unfixed human cadaver temporal bones underwent intratympanic IBCA injection using three sequentially studied methods. The first method was direct IT injection. The second method used direct RWM visualization via tympanomeatal flap for IBCA-soaked absorbable gelatin pledget placement. In the third method, the middle ear was filled with contrast after flap elevation. Volume acquisition CT images were obtained immediately post-exposure, and at 1, 6, and 24 hour intervals. Post-processing was accomplished using color ramping and subtraction imaging. Results Following the third method, positive RWM and perilymphatic enhancement were seen with endolymph sparing. Gray scale and color ramp multiplanar reconstructions displayed increased signal within the cochlea compared to pre-contrast imaging. The cochlea was measured for attenuation differences compared to pure water, revealing a pre-injection average of −1,103 HU and a post-injection average of 338 HU. Subtraction imaging shows enhancement remaining within the cochlear space, Eustachian tube, middle ear epithelial lining, and mastoid. Conclusions Iohexol iodine contrast is able to diffuse across the RWM. Volume acquisition CT imaging was able to detect perilymphatic enhancement at 0.5mm slice thickness. The clinical application of IBCA IT injection appears promising but requires further safety studies. PMID:26859543

Respiratory response to microinjections of GABA and penicillin into various parts of the ventral respiratory group.

PubMed

Vedyasova, O A; Kovalyov, A M

2012-06-01

Experiments on rats showed that local injection of GABA (10(-4) M) into the rostral and caudal compartments of the ventral respiratory groups decreased the respiratory rhythm, but increased lung ventilation (especially injection into the rostral part). Penicillin (10(-7) M) injected into the rostral division increased the tidal volume and practically did not change the respiratory rate, but its injection into the caudal part reduced the tidal volume and increased respiratory rate. These results indicate that GABAergic mechanisms including GABA(A) sites play an ambiguous role in the regulation of respiration at the level of the rostral and caudal parts of the ventral respiratory group.

Method and apparatus for controlling cross contamination of microfluid channels

DOEpatents

Hasselbrink, Jr., Ernest F.; Rehm, Jason E [Alameda, CA; Paul, Phillip H [Livermore, CA; Arnold, Don W [Livermore, CA

2006-02-07

A method for controlling fluid flow at junctions in microchannel systems. Control of fluid flow is accomplished generally by providing increased resistance to electric-field and pressure-driven flow in the form of regions of reduced effective cross-sectional area within the microchannels and proximate a channel junction. By controlling these flows in the region of a microchannel junction it is possible to eliminate sample dispersion and cross contamination and inject well-defined volumes of fluid from one channel to another.

Determination of Caffeine in Beverages by Capillary Zone Electrophoresis: An Experiment for the Undergraduate Analytical Laboratory

NASA Astrophysics Data System (ADS)

Conte, Eric D.; Barry, Eugene F.; Rubinstein, Harry

1996-12-01

Certain individuals may be sensitive to specific compounds in comsumer products. It is important to quantify these analytes in food products in order to monitor their intake. Caffeine is one such compound. Determination of caffeine in beverages by spectrophotometric procedures requires an extraction procedure, which can prove time-consuming. Although the corresponding determination by HPLC allows for a direct injection, capillary zone electrophoresis provides several advantages such as extremely low solvent consumption, smaller sample volume requirements, and improved sensitivity.

High volume ultrasound guided injections at the interface between the patellar tendon and Hoffa's body are effective in chronic patellar tendinopathy: A pilot study.

PubMed

Crisp, Tom; Khan, Faisal; Padhiar, Nat; Morrissey, Dylan; King, John; Jalan, Rosy; Maffulli, Nicola; Frcr, Otto Chan

2008-01-01

To evaluate a novel conservative management modality for patellar tendinopathy. We recruited nine patients with patellar tendinopathy who had failed conservative management and showed evidence of neovascularisation on power Doppler scanning. A high volume ultrasound guided injection at the interface between the patellar tendon and Hoffa's body. The injection contained 10 ml 0.5% Bupivacaine, 25 mg Hydrocortisone, and between 12 and 40 ml normosaline. 100 mm visual analogue scales (VAS) for pain and for function, and Victorian Institute of Sport Assessment - Patellar tendon (VISA-P) questionnaires at an average of 9 months from the injection. All but one patient (whose pain was unchanged) improved (p = 0.028). The mean improvement in function 2 weeks after injection was 58 mm on VAS (interquartile range 27 - 88, p = 0.018). The mean improvement in pain 2 weeks after injection was 56 mm on a VAS scale (interquartile range 32 - 80, p = 0.018). At a mean follow up of 9 months, an improvement of 22 points from a baseline score of 46 on the VISA-P questionnaire (100 being normal) was established. High volume injections to mechanically disrupt the neovascularisation in patellar tendinopathy are helpful in the management of this condition. Controlled trials would be warranted to investigate in a more conclusive fashion this management modality.

Exploratory experiments to determine the effect of alternative operations on the efficiency of subsurface arsenic removal in rural Bangladesh

NASA Astrophysics Data System (ADS)

Rahman, M. M.; Bakker, M.; Freitas, S. C. Borges; van Halem, D.; van Breukelen, B. M.; Ahmed, K. M.; Badruzzaman, A. B. M.

2015-02-01

The principle of subsurface arsenic (As) removal (SAR) is to extract anoxic groundwater, aerate it and re-inject it. Oxygen in the injected water reacts with iron in the resident groundwater to form hydrous ferric oxide (HFO). Dissolved As sorbs onto the HFO, which allows for the extraction of groundwater with lower As concentrations. SAR was applied at a rural location in Bangladesh (As in groundwater = 200 μg/L) to study the effect of different operational parameters on SAR performance, including repeated injection and extraction of an equal volume, lower pumping rate, and intermittent pumping. Larger injection volume, lower pumping rate, and intermittent pumping all had positive effects on As removal indicating that As adsorption is kinetically limited. Repeated injection-extraction of an equal volume improved As removal efficiency by providing more HFO for sorption. After injection of 1,000 L, a maximum of 3,000 L of `safe' water, as defined by the Bangladesh national standard for As (<50 μg/L), was extracted, of which 2,000 L can be used as drinking water and the remainder is used for re-injection. Under this setup, the estimated cost for 1,000 L of As-safe drinking water is US2.00, which means that SAR is a viable mitigation option for rural areas.

The U.S. Gas Flooding Experience: CO2 Injection Strategies and Impact on Ultimate Recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nunez-Lopez, Vanessa; Hosseini, Seyyed; Gil-Egui, Ramon

The Permian Basin in West Texas and southwestern New Mexico has seen 45 years of oil reserve growth through CO2 enhanced oil recovery (CO2 EOR). More than 60 CO2 EOR projects are currently active in the region’s limestone, sandstone and dolomite reservoirs. Water alternating gas (WAG) has been the development strategy of choice in the Permian for several technical and economic reasons. More recently, the technology started to get implemented in the much more porous and permeable clastic depositional systems of the onshore U.S. Gulf Coast. Continued CO2 injection (CGI), as opposed to WAG, was selected as the injection strategymore » to develop Gulf Coast oil fields, where CO2 injection volumes are significantly larger (up to 6 times larger) than those of the Permian. We conducted a compositional simulation based study with the objective of comparing the CO2 utilization ratios (volume of CO2 injected to produce a barrel of oil) of 4 conventional and novel CO2 injection strategies: (1) continuous gas injection (CGI), (2) water alternating gas (WAG), (3) water curtain injection (WCI), and (4) WAG and WCI combination. These injection scenarios were simulated using the GEM module from the Computer Modeling Group (CMG). GEM is an advanced general equation-of-state compositional simulator, which includes equation of state, CO2 miscible flood, CO2/brine interactions, and complex phase behavior. The simulator is set up to model three fluid phases including water, oil, and gas. Our study demonstrates how the selected field development strategy has a significant impact on the ultimate recovery of CO2-EOR projects, with GCI injection providing maximum oil recovery in absolute volume terms, but with WAG offering a more balanced technical-economical approach.« less

Influence of hypodermic needle dimensions on subcutaneous injection delivery--a pig study of injection deposition evaluated by CT scanning, histology, and backflow.

PubMed

Juul, Kezia Ann Praestmark; Bengtsson, Henrik; Eyving, Bente; Kildegaard, Jonas; Lav, Steffen; Poulsen, Mette; Serup, Jørgen; Stallknecht, Bente

2012-11-01

Thinner and shorter needles for subcutaneous administration are continuously developed. Previous studies have shown that a thinner needle causes fewer occurrences of painful needle insertions and that a shorter needle decreases the occurrence of painful intramuscular injections. However, little is known about local drug delivery in relation to needle length and thickness. This study aimed to compare deposition depth and backflow from three hypodermic needles of 3 mm 34G (0.19 mm), 5 mm 32G (0.23 mm), and 8 mm 30G (0.30 mm) in length and thickness. Ex vivo experiments were carried out on pigs, in neck tissue comparable to human skin at typical injection sites. Six pigs were included and a total of 72 randomized injections were given, i.e. 24 subcutaneous injections given with each needle type. Accordingly, 400 μL was injected including 70% NovoRapid(®) (Novo Nordisk A/S, Bagsvμrd, Denmark) and 30% Xenetix(®) (Guerbet, Villepinte, France) contrast including 1 mg/mL Alcian blue. Surgical biopsies of injection sites were sampled and computer topographic (CT)-scanned in 3D to assess deposition and local distribution. Biopsies were prepared and stained to evaluate deposition in comparison to the CT-scanning findings. The backflow of each injection was collected with filter paper. The blue stains of filter paper were digitized and volume estimated by software calculation vs. control staining. CT-scanning (n = 57) and histology (n = 10) showed that, regardless of injection depth, the bulk of the injection was in the subcutaneous tissue and did not propagate from subcutis into dermis. With the 8 mm 30G needle all injections apart from one intramuscular injection were located in the subcutaneous layer. The volume depositions peaked in 4-5 mm depth for the 3 mm 34G needle, in 5-6 mm depth for the 5 mm 32G needle, and in 9-10 mm depth for the 8 mm 30G needle. In general, injection depositions evaluated by histology and CT-scans compared well for the individual biopsies. The amount of backflow (n = 69) from the 3 mm 34G needle was smaller (P < 0.05) as compared to the 5 mm 32G and the 8 mm 30G needles. Analysis showed a correlation between backflow and the needle's outer dimension with the needle diameter being the pivotal parameter. Furthermore, CT-scanning and histology confirmed that local propagation of the injection and final distribution followed a route of less mechanical resistance as determined by connective tissue barriers preset in the site of injection. Needles as short as 3 mm efficiently delivered injections into the subcutaneous target. The amount of backflow was smaller with thinner needles. Local distribution was variable and determined by mechanical barriers preset in the tissue. CT-scans and histology were concordant. © 2012 John Wiley & Sons A/S.

A Bioimpedance Analysis Platform for Amputee Residual Limb Assessment.

PubMed

Sanders, Joan E; Moehring, Mark A; Rothlisberger, Travis M; Phillips, Reid H; Hartley, Tyler; Dietrich, Colin R; Redd, Christian B; Gardner, David W; Cagle, John C

2016-08-01

The objective of this research was to develop a bioimpedance platform for monitoring fluid volume in residual limbs of people with trans-tibial limb loss using prostheses. A customized multifrequency current stimulus profile was sent to thin flat electrodes positioned on the thigh and distal residual limb. The applied current signal and sensed voltage signals from four pairs of electrodes located on the anterior and posterior surfaces were demodulated into resistive and reactive components. An established electrical model (Cole) and segmental limb geometry model were used to convert results to extracellular and intracellular fluid volumes. Bench tests and testing on amputee participants were conducted to optimize the stimulus profile and electrode design and layout. The proximal current injection electrode needed to be at least 25 cm from the proximal voltage sensing electrode. A thin layer of hydrogel needed to be present during testing to ensure good electrical coupling. Using a burst duration of 2.0 ms, intermission interval of 100 μs, and sampling delay of 10 μs at each of 24 frequencies except 5 kHz, which required a 200-μs sampling delay, the system achieved a sampling rate of 19.7 Hz. The designed bioimpedance platform allowed system settings and electrode layouts and positions to be optimized for amputee limb fluid volume measurement. The system will be useful toward identifying and ranking prosthetic design features and participant characteristics that impact residual limb fluid volume.

An Ultra-Sensitive Method for the Analysis of Perfluorinated ...

EPA Pesticide Factsheets

In epidemiological research, it has become increasingly important to assess subjects' exposure to different classes of chemicals in multiple environmental media. It is a common practice to aliquot limited volumes of samples into smaller quantities for specific trace level chemical analysis. A novel method was developed for the determination of 14 perfluorinated alkyl acids (PFAAs) in small volumes (10 mL) of drinking water using off-line solid phase extraction (SPE) pre-treatment followed by on-line pre-concentration on WAX column before analysis on column-switching high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In general, large volumes (100 - 1000 mL) have been used for the analysis of PFAAs in drinking water. The current method requires approximately 10 mL of drinking water concentrated by using an SPE cartridge and eluted with methanol. A large volume injection of the extract was introduced on to a column-switching HPLC-MS/MS using a mix-mode SPE column for the trace level analysis of PFAAs in water. The recoveries for most of the analytes in the fortified laboratory blanks ranged from 73±14% to 128±5%. The lowest concentration minimum reporting levels (LCMRL) for the 14 PFAAs ranged from 0.59 to 3.4 ng/L. The optimized method was applied to a pilot-scale analysis of a subset of drinking water samples from an epidemiological study. These samples were collected directly from the taps in the households of Ohio and Nor

Isothermal titration calorimetry in nanoliter droplets with subsecond time constants.

PubMed

Lubbers, Brad; Baudenbacher, Franz

2011-10-15

We reduced the reaction volume in microfabricated suspended-membrane titration calorimeters to nanoliter droplets and improved the sensitivities to below a nanowatt with time constants of around 100 ms. The device performance was characterized using exothermic acid-base neutralizations and a detailed numerical model. The finite element based numerical model allowed us to determine the sensitivities within 1% and the temporal dynamics of the temperature rise in neutralization reactions as a function of droplet size. The model was used to determine the optimum calorimeter design (membrane size and thickness, junction area, and thermopile thickness) and sensitivities for sample volumes of 1 nL for silicon nitride and polymer membranes. We obtained a maximum sensitivity of 153 pW/(Hz)(1/2) for a 1 μm SiN membrane and 79 pW/(Hz)(1/2) for a 1 μm polymer membrane. The time constant of the calorimeter system was determined experimentally using a pulsed laser to increase the temperature of nanoliter sample volumes. For a 2.5 nanoliter sample volume, we experimentally determined a noise equivalent power of 500 pW/(Hz)(1/2) and a 1/e time constant of 110 ms for a modified commercially available infrared sensor with a thin-film thermopile. Furthermore, we demonstrated detection of 1.4 nJ reaction energies from injection of 25 pL of 1 mM HCl into a 2.5 nL droplet of 1 mM NaOH. © 2011 American Chemical Society

Sequential injection system for simultaneous determination of sucrose and phosphate in cola drinks using paired emitter-detector diode sensor.

PubMed

Saetear, Phoonthawee; Khamtau, Kittiwut; Ratanawimarnwong, Nuanlaor; Sereenonchai, Kamonthip; Nacapricha, Duangjai

2013-10-15

This work presents the simultaneous determination of sucrose and phosphate by using sequential injection (SI) system with a low cost paired emitter-detector diode (PEDD) light sensor. The PEDD uses two 890 nm LEDs. Measurement of sucrose in Brix unit was carried out based on the detection of light refraction occurring at the liquid interface (the schlieren effect) between the sucrose solution and water. Phosphate was measured from the formation of calcium phosphate with turbidimetric detection. With careful design of the loading sequence and volume (sample--precipitating reagent--sample), simultaneous detection of sucrose and phosphate was accomplished with the single PEDD detector. At the optimized condition, linear calibrations from 1 to 7 Brix sucrose and from 50 to 200mg PO4(3-)L(-1) were obtained. Good precision at lower than 2% RSD (n=10) for both analytes with satisfactory throughput of 21 injections h(-1) was achieved. The method was successfully applied for the determination of sucrose and phosphate in cola drinks. The proposed method is readily applicable for automation and is found to be an alternative method to conventional procedures for on-line quality control process in cola drink industry. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Optimization of programmed-temperature vaporization injection preparative capillary GC for compound specific radiocarbon analysis.

PubMed

Zhang, Xinyu; Zhao, Liang; Wang, Yexin; Xu, Yunping; Zhou, Liping

2013-07-01

Preparative capillary GC (PCGC) is a powerful tool for the separation and purification of compounds from any complex matrix, which can be used for compound-specific radiocarbon analysis. However, the effect of PCGC parameters on the trapping efficiency is not well understood. Here, we present a comprehensive study on the optimization of parameters based on 11 reference compounds with different physicochemical properties. Under the optimum conditions, the trapping efficiencies of these 11 compounds (including high-boiling-point n-hentriacontane and methyl lignocerate) are about 80% (60-89%). The isolation of target compounds from standard solutions, plant and soil samples demonstrates that our optimized method is applicable for different classes of compounds including n-alkanes, fatty acid esters, long-chain fatty alcohol esters, polycyclic aromatic hydrocarbons (PAHs) and steranes. By injecting 25 μL in large volume injection mode, over 100 μg, high purity (>90%) target compounds are harvested within 24 h. The recovery ranges of two real samples are about 70% (59.9-83.8%) and about 83% (77.2-88.5%), respectively. Compared to previous studies, our study makes significant improvement in the recovery of PCGC, which is important for its wide application in biogeochemistry, environmental sciences, and archaeology. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid injectable silicone: a review of its history, immunology, technical considerations, complications, and potential.

PubMed

Narins, Rhoda S; Beer, Kenneth

2006-09-01

For over five decades, liquid injectable silicone has been used for soft-tissue augmentation. Its use has engendered polarized reactions from the public and from physicians. Adherents of this product tout its inert chemical structure, ease of use, and low cost. Opponents of silicone cite the many reports of complications, including granulomas, pneumonitis, and disfiguring nodules that are usually the result of large-volume injection and/or industrial grade or adulterated material. Unfortunately, as recently as 2006, reports in The New England Journal of Medicine and The New York Times failed to distinguish between the use of medical grade silicone injected by physicians trained in the microdroplet technique and the use of large volumes of industrial grade products injected by unlicensed or unskilled practitioners. This review separates these two markedly different procedures. In addition, it provides an overview of the chemical structure of liquid injectable silicone, the immunology of silicone reactions within the body, treatment for cosmetic improvement including human immunodeficiency virus lipoatrophy, technical considerations for its injection, complications seen following injections, and some considerations of the future for silicone soft-tissue augmentation.

Persulfate injection into a gasoline source zone.

PubMed

Sra, Kanwartej S; Thomson, Neil R; Barker, Jim F

2013-07-01

One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O8(2-), SO4(2-), Na(+), dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for >10months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in [Formula: see text] indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M˙DIC increased by >100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone. Copyright © 2013 Elsevier B.V. All rights reserved.

Tracer-monitored flow titrations.

PubMed

Sasaki, Milton K; Rocha, Diogo L; Rocha, Fábio R P; Zagatto, Elias A G

2016-01-01

The feasibility of implementing tracer-monitored titrations in a flow system is demonstrated. A dye tracer is used to estimate the instant sample and titrant volumetric fractions without the need for volume, mass or peak width measurements. The approach was applied to spectrophotometric flow titrations involving variations of sample and titrant flow-rates (i.e. triangle programmed technique) or concentration gradients established along the sample zone (i.e. flow injection system). Both strategies required simultaneous monitoring of two absorbing species, namely the titration indicator and the dye tracer. Mixing conditions were improved by placing a chamber with mechanical stirring in the analytical path aiming at to minimize diffusional effects. Unlike most of flow-based titrations, the innovation is considered as a true titration, as it does not require a calibration curve thus complying with IUPAC definition. As an application, acidity evaluation in vinegars involving titration with sodium hydroxide was selected. Phenolphthalein and brilliant blue FCF were used as indicator and dye tracer, respectively. Effects of sample volume, titrand/titrant concentrations and flow rates were investigated aiming at improved accuracy and precision. Results were reliable and in agreement with those obtained by a reference titration procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

Combination of micelle collapse and field-amplified sample stacking in capillary electrophoresis for determination of trimethoprim and sulfamethoxazole in animal-originated foodstuffs.

PubMed

Liu, Lihong; Wan, Qian; Xu, Xiaoying; Duan, Shunshan; Yang, Chunli

2017-03-15

An on-line preconcentration method combining micelle to solvent stacking (MSS) with field-amplified sample stacking (FASS) was employed for the analysis of trimethoprim (TMP) and sulfamethoxazole (SMZ) by capillary zone electrophoresis (CZE). The optimized experimental conditions were as followings: (1) sample matrix, 10.0mM SDS-5% (v/v) methanol; (2) trapping solution (TS), 35mM H 3 PO 4 -60% acetonitrile (CH 3 CN); (3) running buffer, 30mM Na 2 HPO 4 (pH=7.3); (4) sample solution volume, 168nL; TS volume, 168nL; and (5) 9kV voltage, 214nm UV detection. Under the optimized conditions, the limits of detection (LODs) for SMZ and TMP were 7.7 and 8.5ng/mL, and they were 301 and 329 times better compared to a typical injection, respectively. The contents of TMP and SMZ in animal foodstuffs such as dairy products, eggs and honey were analyzed, too. Recoveries of 80-104% were acquired with relative standard deviations of 0.5-5.4%. Copyright © 2016 Elsevier Ltd. All rights reserved.

An on-line SPE-HPLC method for effective sample preconcentration and determination of fenoxycarb and cis, trans-permethrin in surface waters.

PubMed

Šatínský, Dalibor; Naibrtová, Linda; Fernández-Ramos, Carolina; Solich, Petr

2015-09-01

A new on-line SPE-HPLC method using fused-core columns for on-line solid phase extraction and large volume sample injection for increasing the sensitivity of detection was developed for the determination of insecticides fenoxycarb and cis-, trans-permethrin in surface waters. The separation was carried out on fused-core column Phenyl-Hexyl (100×4.6 mm), particle size 2.7 µm with mobile phase acetonitrile:water in gradient mode at flow rate 1.0 mL min(-1), column temperature 45°C. Large volume sample injection (1500 µL) to the extraction dimension using short precolumn Ascentis Express RP C-18 (5×4.6 mm); fused-core particle size 2.7 µm allowed effective sample preconcentration and efficient ballast sample matrix removal. The washing mobile phase consisting of a mixture of acetonitrile:water; 30:70, (v/v) was pumped at flow rate of 0.5 mL min(-1) through the extraction precolumn to the waste. Time of the valve switch for transferring the preconcentrated sample zone from the extraction to the separation column was set at 3rd min. Elution of preconcentrated insecticides from the extraction precolumn and separation on the analytical column was performed in gradient mode. Linear gradient elution started from 40% of acetonitrile at time of valve switch from SPE column (3rd min) to 95% of acetonitrile at 7th min. Synthetic dye sudan I was chosen as an internal standard. UV detection at wavelength 225 nm was used and the method reached the limits of detection (LOD) at ng mL(-1) levels for both insecticides. The method showing on-line sample pretreatment and preconcentration with highly sensitive determination of insecticides was applied for monitoring of fenoxycarb and both permethrin isomers in different surface water samples in Czech Republic. The time of whole analysis including on-line extraction, interferences removal, chromatography separation and system equilibration was less than 8 min. Copyright © 2015 Elsevier B.V. All rights reserved.

Single well tracer method to evaluate enhanced recovery

DOEpatents

Sheely, Jr., Clyde Q.; Baldwin, Jr., David E.

1978-01-01

Data useful to evaluate the effectiveness of or to design an enhanced recovery process (the recovery process involving mobilizing and moving hydrocarbons through a hydrocarbon-bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well) are obtained by a process which comprises sequentially: determining hydrocarbon saturation in the formation in a volume in the formation near a well bore penetrating the formation, injecting sufficient of the mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore penetrating the formation, and determining by the single well tracer method a hydrocarbon saturation profile in a volume from which hydrocarbons are moved. The single well tracer method employed is disclosed by U.S. Pat. No. 3,623,842. The process is useful to evaluate surfactant floods, water floods, polymer floods, CO.sub.2 floods, caustic floods, micellar floods, and the like in the reservoir in much less time at greatly reduced costs, compared to conventional multi-well pilot test.

Contrast administration and techniques of digital subtraction angiography performance.

PubMed

Saddekni, S; Sos, T A; Srur, M; Cohn, D J

1985-06-01

Optimal IV-DSA performance depends equally on the digital system, the patient, and the radiologist. Through enhancement and subtraction, the digital system increases contrast sensitivity, thus compensating for the relatively low spatial resolution and for the loss in contrast (density) that results from dilution of the contrast medium by injecting it on the venous side. The degree of this dilution is governed by the patient's cardiac output and the size of the central blood volume. The lower the cardiac output and the larger the central blood volume, the less opacification (more dilution) and longer transit time (more likelihood for artifacts) will result. The role of the radiologist is to optimize the available conditions. He can prevent measures that decrease cardiac output (Valsalva maneuver) or he can take measures to decrease the degree of dilution by choosing optimal contrast administration methods, such as injecting in the right atrium at a high rate and thus allowing more latitude to decrease the total volume per injection and to increase the number of injections per examination. The radiologist also attempts to combat all the sources of noninformation or misinformation resulting from voluntary or involuntary patient motion, which degrades subtraction. By observing studies in real time, the radiologist may recognize motion during the injection, and by increasing the number of exposures, he may have a late mask to save the study. On immediate review of an injection, he may recognize the need to increase the volume per injection to obtain better opacification or, conversely, to reduce the volume if it is apparent that it could be done without compromise to the study and yet allow more injections to be performed, or he may recognize a finding that requires more than the usual routine views and may obtain a better one. IV-DSA can be performed with peripheral injections of contrast medium if the area of interest is limited and superior opacification is not essential, especially if a larger image intensifier (12- to 16-inch field) is available. However, whether peripheral injections are the least invasive, depends on whether one thinks that 200 to 240 ml of Renografin-76 for four views in an outpatient is invasive or not. The notion that IV-DSA can be performed by a nurse who places the IV needle or angiocatheter, a technician who shoots the pictures, and a computer that will do the rest, while the radiologist is peripherally involved and to hope for consistently good studies, is far from realistic.(ABSTRACT TRUNCATED AT 400 WORDS)

Botulinum Toxin Type A Injections in the Psoas Muscle of Children with Cerebral Palsy: Muscle Atrophy after Motor End Plate-Targeted Injections

ERIC Educational Resources Information Center

Van Campenhout, Anja; Verhaegen, Ann; Pans, Steven; Molenaers, Guy

2013-01-01

MEP targeting during BoNT-A injections has been demonstrated to improve outcome. Two injection techniques of the psoas muscle--proximal MEP targeting versus a widely used more distal injection technique--are compared using muscle volume assessment by digital MRI segmentation as outcome measure. Method: 7 spastic diplegic children received…

Systematic assessment of microneedle injection into the mouse cornea

PubMed Central

2012-01-01

Background Corneal intrastromal injection is an important mode of gene-vector application to subepithelial layers. In a mouse model, this procedure is substantially complicated by the reduced corneal dimensions. Furthermore, it may be difficult to estimate the corneal area reached by the volume of a single injection. This study aimed to investigate intrastromal injections into the mouse cornea using different microneedles and to quantify the effect of injecting varying volumes. A reproducible injection technique is described. Methods Forty eyes of 20 129 Sv/J mice were tested. India ink was intrastromally injected using 30° beveled 33 G needles, tri-surface 25° beveled 35 G needles, or hand-pulled and 25° beveled glass needles. Each eye received a single injection of a volume of 1 or 2 μL. Corneoscleral buttons were fixed and flat mounted for computer-assisted quantification of the affected corneal area. Histological assessment was performed to investigate the intrastromal location of the injected dye. Results A mean corneal area of 5.0 ±1.4 mm2 (mean ± SD) and 7.7 ±1.4 mm2 was covered by intrastromal injections of 1 and 2 μL, respectively. The mean percentage of total corneal area reached ranged from 39% to 53% for 1 μL injections, and from 65% to 81% for 2 μL injections. Injections using the 33 G needles tended to provide the highest distribution area. Perforation rates were 8% for 30° beveled 33 G needles and 44% for tri-surface beveled 35 G needles. No perforation was observed with glass needle; however, intrastromal breakage of needle tips was noted in 25% of these cases. Conclusions Intracorneal injection using a 30° beveled 33 G needle was safe and effective. The use of tri-surface beveled 35 G needles substantially increased the number of corneal perforations. Glass needles may break inside the corneal stroma. Injections of 1 μL and 2 μL resulted in an overall mean of 49% and 73% respectively of total corneal area involved. PMID:22716296

Relationships between Induced Seismicity and Fluid Injection: Development of Strategies to Manage Injection

NASA Astrophysics Data System (ADS)

Eichhubl, Peter; Frohlich, Cliff; Gale, Julia; Olson, Jon; Fan, Zhiqiang; Gono, Valerie

2014-05-01

Induced seismicity during or following the subsurface injection of waste fluids such as well stimulation flow back and production fluids has recently received heightened public and industry attention. It is understood that induced seismicity occurs by reactivation of existing faults that are generally present in the injection intervals. We seek to address the question why fluid injection triggers earthquakes in some areas and not in others, with the aim toward improved injection methods that optimize injection volume and cost while avoiding induced seismicity. A GIS database has been built of natural and induced earthquakes in four hydrocarbon-producing basins: the Fort Worth Basin, South Texas, East Texas/Louisiana, and the Williston Basin. These areas are associated with disposal from the Barnett, Eagle Ford, Bakken, and Haynesville Shales respectively. In each region we analyzed data that were been collected using temporary seismographs of the National Science Foundation's USArray Transportable Array. Injection well locations, formations, histories, and volumes are also mapped using public and licensed datasets. Faults are mapped at a range of scales for selected areas that show different levels of seismic activity, and scaling relationships used to extrapolate between the seismic and wellbore scale. Reactivation potential of these faults is assessed using fault occurrence, and in-situ stress conditions, identifying areas of high and low fault reactivation potential. A correlation analysis between fault reactivation potential, induced seismicity, and fluid injection will use spatial statistics to quantify the probability of seismic fault reactivation for a given injection pressure in the studied reservoirs. The limiting conditions inducing fault reactivation will be compared to actual injection parameters (volume, rate, injection duration and frequency) where available. The objective of this project is a statistical reservoir- to basin-scale assessment of fault reactivation and seismicity induced by fluid injection. By assessing the occurrence of earthquakes (M>2) evenly across large geographic regions, this project differs from previous studies of injection-induced seismicity that focused on earthquakes large enough to cause public concern in well-populated areas. The understanding of triggered seismicity gained through this project is expected to allow for improved design strategies for waste fluid injection to industry and public decision makers.

Systematic assessment of microneedle injection into the mouse cornea.

PubMed

Matthaei, Mario; Meng, Huan; Bhutto, Imran; Xu, Qingguo; Boelke, Edwin; Hanes, Justin; Jun, Albert S

2012-06-20

Corneal intrastromal injection is an important mode of gene-vector application to subepithelial layers. In a mouse model, this procedure is substantially complicated by the reduced corneal dimensions. Furthermore, it may be difficult to estimate the corneal area reached by the volume of a single injection. This study aimed to investigate intrastromal injections into the mouse cornea using different microneedles and to quantify the effect of injecting varying volumes. A reproducible injection technique is described. Forty eyes of 20 129 Sv/J mice were tested. India ink was intrastromally injected using 30° beveled 33 G needles, tri-surface 25° beveled 35 G needles, or hand-pulled and 25° beveled glass needles. Each eye received a single injection of a volume of 1 or 2 μL. Corneoscleral buttons were fixed and flat mounted for computer-assisted quantification of the affected corneal area. Histological assessment was performed to investigate the intrastromal location of the injected dye. A mean corneal area of 5.0 ± 1.4 mm(2) (mean ± SD) and 7.7 ± 1.4 mm(2) was covered by intrastromal injections of 1 and 2 μL, respectively. The mean percentage of total corneal area reached ranged from 39% to 53% for 1 μL injections, and from 65% to 81% for 2 μL injections. Injections using the 33 G needles tended to provide the highest distribution area. Perforation rates were 8% for 30° beveled 33 G needles and 44% for tri-surface beveled 35 G needles. No perforation was observed with glass needle; however, intrastromal breakage of needle tips was noted in 25% of these cases. Intracorneal injection using a 30° beveled 33 G needle was safe and effective. The use of tri-surface beveled 35 G needles substantially increased the number of corneal perforations. Glass needles may break inside the corneal stroma. Injections of 1 μL and 2 μL resulted in an overall mean of 49% and 73% respectively of total corneal area involved.

Extraction and Determination of Cyproheptadine in Human Urine by DLLME-HPLC Method

PubMed Central

Maham, Mehdi; Kiarostami, Vahid; Waqif-Husain, Syed; Abroomand-Azar, Parviz; Tehrani, Mohammad Saber; Khoeini Sharifabadi, Malihe; Afrouzi, Hossein; Shapouri, MahmoudReza; Karami-Osboo, Rouhollah

2013-01-01

Novel dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography with photodiode array detection (HPLC-DAD) has been applied for the extraction and determination of cyproheptadine (CPH), an antihistamine, in human urine samples. In this method, 0.6 mL of acetonitrile (disperser solvent) containing 30 μL of carbon tetrachloride (extraction solvent) was rapidly injected by a syringe into 5 mL urine sample. After centrifugation, the sedimented phase containing enriched analyte was dissolved in acetonitrile and an aliquot of this solution injected into the HPLC system for analysis. Development of DLLME procedure includes optimization of some important parameters such as kind and volume of extraction and disperser solvent, pH and salt addition. The proposed method has good linearity in the range of 0.02-4.5 μg mL-1 and low detection limit (13.1 ng mL-1). The repeatability of the method, expressed as relative standard deviation was 4.9% (n = 3). This method has also been applied to the analysis of real urine samples with satisfactory relative recoveries in the range of 91.6-101.0%. PMID:24250605

Visual and portable strategy for copper(II) detection based on a striplike poly(thymine)-caged and microwell-printed hydrogel.

PubMed

Qing, Zhihe; Mao, Zhengui; Qing, Taiping; He, Xiaoxiao; Zou, Zhen; He, Dinggeng; Shi, Hui; Huang, Jin; Liu, Jianbo; Wang, Kemin

2014-11-18

Due to its importance to develop strategies for copper(II) (Cu(2+)) detection, we here report a visual and portable strategy for Cu(2+) detection based on designing and using a strip-like hydrogel. The hydrogel is functionalized through caging poly(thymine) as probes, which can effectively template the formation of fluorescent copper nanoparticles (CuNPs) in the presence of the reductant (ascorbate) and Cu(2+). On the hydrogel's surface, uniform wells of microliter volume (microwells) are printed for sample-injection. When the injected sample is stained by Cu(2+), fluorescent CuNPs will be in situ templated by poly T in the hydrogel. With ultraviolet (UV) irradiation, the red fluorescence of CuNPs can be observed by naked-eye and recorded by a common camera without complicated instruments. Thus, the strategy integrates sample-injection, reaction and indication with fast signal response, providing an add-and-read manner for visual and portable detection of Cu(2+), as well as a strip-like strategy. Detection ability with a detectable minimum concentration of 20 μM and practically applicable properties have been demonstrated, such as resistance to environmental interference and good constancy, indicating that the strategy holds great potential and significance for popular detection of Cu(2+), especially in remote regions. We believe that the strip-like hydrogel-based methodology is also applicable to other targets by virtue of altering probes.

Simultaneous detection of antibacterial sulfonamides in a microfluidic device with amperometry.

PubMed

Won, So-Young; Chandra, Pranjal; Hee, Tak Seong; Shim, Yoon-Bo

2013-01-15

A highly sensitive and robust method for simultaneous detection of five sulfonamide drugs is developed by integrating the preconcentration and separation steps in a microfluidic device. An ampetrometry is performed for the selective detection of sulfonamides using an aluminum oxide-gold nanoparticle (Al(2)O(3)-AuNPs) modified carbon paste (CP) electrode at the end of separation channel. The preconcentration capacity of the channel is enhanced by using the field amplified sample stacking and the field amplified sample injection techniques. The experimental parameters affecting the analytical performances, such as pH, % of Al(2)O(3), volume of AuNPs, buffer concentration, and water plug length are optimized. A reproducible response is observed during the multiple injections of samples with RSDs<4%. The calibration plots are linear with the correlation coefficient between 0.991 and 0.997 over the range between 0.01 and 2025pM. The detection limits of five drugs are determined to be between 0.91 (±0.03) and 2.21 (±0.09)fM. The interference effects of common biological compounds are also investigated and the applicability of the method to the direct analysis of sulfonamides in real meat samples is successfully demonstrated. Long term stability of the modified electrode was also investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

The duration of hyaluronidase and optimal timing of hyaluronic acid (HA) filler reinjection after hyaluronidase injection.

PubMed

Kim, H J; Kwon, S B; Whang, K U; Lee, J S; Park, Y L; Lee, S Y

2018-02-01

Hyaluronidase injection is a commonly performed treatment for overcorrection or misplacement of hyaluronic acid (HA) filler. Many patients often wants the HA filler reinjection after the use of hyaluronidase, though the optimal timing of reinjection of HA filler still remains unknown. To provide the optimal time interval between hyaluronidase injections and HA filler reinjections. 6 Sprague-Dawley rats were injected with single monophasic HA filler. 1 week after injection, the injected sites were treated with hyaluronidase. Then, HA fillers were reinjected sequentially with differing time intervals from 30 minutes to 14 days. 1 hour after the reinjection of the last HA filler, all injection sites were excised for histologic evaluation. 3 hours after reinjection of HA filler, the appearance of filler material became evident again, retaining its shape and volume. 6 hours after reinjection, the filler materials restored almost its original volume and there were no significant differences from the positive control. Our data suggest that the hyaluronidase loses its effect in dermis and subcutaneous tissue within 3-6 hours after the injection and successful engraftment of reinjected HA filler can be accomplished 6 hours after the injection.

Slim hole drilling and testing strategies

NASA Astrophysics Data System (ADS)

Nielson, Dennis L.; Garg, Sabodh K.; Goranson, Colin

2017-12-01

The financial and geologic advantages of drilling slim holes instead of large production wells in the early stages of geothermal reservoir assessment has been understood for many years. However, the practice has not been fully embraced by geothermal developers. We believe that the reason for this is that there is a poor understanding of testing and reservoir analysis that can be conducted in slim holes. In addition to reservoir engineering information, coring through the cap rock and into the reservoir provides important data for designing subsequent production well drilling and completion. Core drilling requires significantly less mud volume than conventional rotary drilling, and it is typically not necessary to cure lost circulation zones (LCZ). LCZs should be tested by either production or injection methods as they are encountered. The testing methodologies are similar to those conducted on large-diameter wells; although produced and/or injected fluid volumes are much less. Pressure, temperature and spinner (PTS) surveys in slim holes under static conditions can used to characterize temperature and pressure distribution in the geothermal reservoir. In many cases it is possible to discharge slim holes and obtain fluid samples to delineate the geochemical properties of the reservoir fluid. Also in the latter case, drawdown and buildup data obtained using a downhole pressure tool can be employed to determine formation transmissivity and well properties. Even if it proves difficult to discharge a slim hole, an injection test can be performed to obtain formation transmissivity. Given the discharge (or injection) data from a slimhole, discharge properties of a large-diameter well can be inferred using wellbore modeling. Finally, slim hole data (pressure, temperature, transmissivity, fluid properties) together with reservoir simulation can help predict the ability of the geothermal reservoir to sustain power production.

Acupuncture injection for field amplified sample stacking and glass microchip-based capillary gel electrophoresis.

PubMed

Ha, Ji Won; Hahn, Jong Hoon

2017-02-01

Acupuncture sample injection is a simple method to deliver well-defined nanoliter-scale sample plugs in PDMS microfluidic channels. This acupuncture injection method in microchip CE has several advantages, including minimization of sample consumption, the capability of serial injections of different sample solutions into the same microchannel, and the capability of injecting sample plugs into any desired position of a microchannel. Herein, we demonstrate that the simple and cost-effective acupuncture sample injection method can be used for PDMS microchip-based field amplified sample stacking in the most simplified straight channel by applying a single potential. We achieved the increase in electropherogram signals for the case of sample stacking. Furthermore, we present that microchip CGE of ΦX174 DNA-HaeⅢ digest can be performed with the acupuncture injection method on a glass microchip while minimizing sample loss and voltage control hardware. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superficial Enhanced Fluid Fat Injection (SEFFI) to Correct Volume Defects and Skin Aging of the Face and Periocular Region.

PubMed

Bernardini, Francesco P; Gennai, Alessandro; Izzo, Luigi; Zambelli, Alessandra; Repaci, Erica; Baldelli, Ilaria; Fraternali-Orcioni, G; Hartstein, Morris E; Santi, Pier Luigi; Quarto, Rodolfo

2015-07-01

Although recent research on micro fat has shown the potential advantages of superficial implantation and high stem cell content, clinical applications thus far have been limited. The authors report their experience with superficial enhanced fluid fat injection (SEFFI) for the correction of volume loss and skin aging of the face in general and in the periocular region. The finer SEFFI preparation (0.5 mL) was injected into the orbicularis in the periorbital and perioral areas, and the 0.8-mL preparation was injected subdermally elsewhere in the face. The records of 98 consecutive patients were reviewed. Average follow-up time was 6 months, and average volume of implanted fat was 20 mL and 51.4 mL for the 0.5-mL and 0.8-mL preparations, respectively. Good or excellent results were achieved for volume restoration and skin improvement in all patients. Complications were minor and included an oil cyst in 3 patients. The smaller SEFFI quantity (0.5 mL) was well suited to correct volume loss in the eyelids, especially the deep upper sulcus and tear trough, whereas the larger SEFFI content was effective for larger volume deficits in other areas of the face, including the brow, temporal fossa, zygomatic-malar region, nasolabial folds, marionette lines, chin, and lips. The fat administered by SEFFI is easily harvested via small side-port cannulae, yielding micro fat that is rich in viable adipocytes and stem cells. Both volumes of fat (0.5 mL and 0.8 mL) were effective for treating age-related lipoatrophy, reducing facial rhytids, and improving skin quality. 4 Therapeutic. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Intra-arterial bolus of 125I labeled meglumine diatrizoate. Early extravascular distribution.

PubMed

Dean, P B; Kormano, M

1977-07-01

A mixture of 125I labeled meglumine diatrizoate and 131I labeled human serum albumin was injected into the lower abdominal aorta of 30 anesthetized, laparotomized male rats. Measurements of the activities in cardiac blood and in different tissues of the hindlimbs and tests were perfomed at six time intervals ranging from 5 seconds to 2 minutes after injection, the determine early uptake and distribution volumes of diatrizoate. Concentrations and distribution volumes were initially much greater than values obtained after intravenous injection, but these differences had considerably decreased or disappeared by 2 minutes.

Does the volume of supplemental intraligamentary injections affect the anaesthetic success rate after a failed primary inferior alveolar nerve block? A randomized-double blind clinical trial.

PubMed

Aggarwal, V; Singla, M; Miglani, S; Kohli, S; Sharma, V; Bhasin, S S

2018-01-01

To investigate the efficacy of 0.2 mL vs. 0.6 mL of 2% lidocaine when given as a supplementary intraligamentary injection after a failed inferior alveolar nerve block (IANB). Ninety-seven adult patients with symptomatic irreversible pulpits received an IANB and root canal treatment was initiated. Pain during treatment was recorded using a visual analogue scale (Heft-Parker VAS). Patients with unsuccessful anaesthesia (n = 78) randomly received intraligamentary injection of either 0.2 mL or 0.6 mL of 2% lidocaine with 1 : 80 000 epinephrine. Root canal treatment was reinitiated. Success after primary injection or supplementary injection was defined as no or mild pain (HP VAS score ≤54 mm) during access preparation and root canal instrumentation. Heart rate was monitored using a finger pulse oximeter. The anaesthetic success rates were analysed with Pearson chi-square test at 5% significance levels. The heart rate changes were analysed using t-tests. The intraligamentary injections with 0.2 mL solution gave an anaesthetic success rate of 64%, whilst the 0.6 mL was successful in 84% of cases with failed primary IANB. (χ 2  = 4.3, P = 0.03). There was no significant effect of the volume of intraligamentary injection on the change in heart rate. Increasing the volume of intraligamentary injection improved the success rates after a failed primary anaesthetic injection. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Photoactivated Composite Biomaterial for Soft Tissue Restoration in Rodents and in Humans

PubMed Central

Nahas, Zayna; Reid, Branden; Coburn, Jeannine M.; Axelman, Joyce; Chae, Jemin J.; Guo, Qiongyu; Trow, Robert; Thomas, Andrew; Hou, Zhipeng; Lichtsteiner, Serge; Sutton, Damon; Matheson, Christine; Walker, Patricia; David, Nathaniel; Mori, Susumu; Taube, Janis M.; Elisseeff, Jennifer H.

2015-01-01

Soft tissue reconstruction often requires multiple surgical procedures that can result in scars and disfiguration. Facial soft tissue reconstruction represents a clinical challenge because even subtle deformities can severely affect an individual’s social and psychological function. We therefore developed a biosynthetic soft tissue replacement composed of poly(ethylene glycol) (PEG) and hyaluronic acid (HA) that can be injected and photocrosslinked in situ with transdermal light exposure. Modulating the ratio of synthetic to biological polymer allowed us to tune implant elasticity and volume persistence. In a small-animal model, implanted photocrosslinked PEG-HA showed a dose-dependent relationship between increasing PEG concentration and enhanced implant volume persistence. In direct comparison with commercial HA injections, the PEG-HA implants maintained significantly greater average volumes and heights. Reversibility of the implant volume was achieved with hyaluronidase injection. Pilot clinical testing in human patients confirmed the feasibility of the transdermal photocrosslinking approach for implantation in abdomen soft tissue, although an inflammatory response was observed surrounding some of the materials. PMID:21795587

Effect of fractionation on treatment outcome in local dual-frequency sonication and Dox-encapsulated nanomicelles.

PubMed

Hasanzadeh, Hadi; Mokhtari-Dizaji, Manijhe; Bathaie, S Zahra; Hassan, Zuhair M

2013-10-01

The goal of this study was to localize drug release from nanomicelles using dual-frequency sonication at low levels of acoustic intensity. In this study, the antitumor effect of simultaneous dual-frequency sonication (28 kHz and 3 MHz) at low levels of acoustic intensity in combination with doxorubicin and micellar doxorubicin injection was assessed in a spontaneous model of breast adenocarcinoma in female Balb/c mice. Sixty-three tumor-bearing mice were randomly grouped into control, sham, dual-frequency sonication, doxorubicin injection with and without dual-frequency sonication, and micellar doxorubicin injection with and without dual-frequency sonication groups. The results of volume change relative to initial volume showed that in the micellar doxorubicin injection with sonication group, this parameter was significantly different from that of the control, sham, sonication, and doxorubicin injection groups (P < 0.05). In addition, the volume began to increase on the 15th day after the start of treatment, which is a good indication to repeat treatment; therefore, another group received an extra treatment on day 15. The animal life span in the micellar doxorubicin with sonication and repeated treatment groups was significantly higher than that in all the other experimental groups except for the micellar doxorubicin injection group (P < 0.05). It was concluded that dual-frequency sonication with micellar doxorubicin injection extends the life span relative to doxorubicin injection or dual-frequency sonication alone, and that repeating this treatment on day 15 decreases the rate of tumor growth significantly.

A Multi-institutional Clinical Trial of Rectal Dose Reduction via Injected Polyethylene-Glycol Hydrogel During Intensity Modulated Radiation Therapy for Prostate Cancer: Analysis of Dosimetric Outcomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Danny Y., E-mail: dsong2@jhmi.edu; Herfarth, Klaus K.; Uhl, Matthias

2013-09-01

Purpose: To characterize the effect of a prostate-rectum spacer on dose to rectum during external beam radiation therapy for prostate cancer and to assess for factors correlated with rectal dose reduction. Methods and Materials: Fifty-two patients at 4 institutions were enrolled into a prospective pilot clinical trial. Patients underwent baseline scans and then were injected with perirectal spacing hydrogel and rescanned. Intensity modulated radiation therapy plans were created on both scans for comparison. The objectives were to establish rates of creation of ≥7.5 mm of prostate-rectal separation, and decrease in rectal V70 of ≥25%. Multiple regression analysis was performed tomore » evaluate the associations between preinjection and postinjection changes in rectal V70 and changes in plan conformity, rectal volume, bladder volume, bladder V70, planning target volume (PTV), and postinjection midgland separation, gel volume, gel thickness, length of PTV/gel contact, and gel left-to-right symmetry. Results: Hydrogel resulted in ≥7.5-mm prostate-rectal separation in 95.8% of patients; 95.7% had decreased rectal V70 of ≥25%, with a mean reduction of 8.0 Gy. There were no significant differences in preinjection and postinjection prostate, PTV, rectal, and bladder volumes. Plan conformities were significantly different before versus after injection (P=.02); plans with worse conformity indexes after injection compared with before injection (n=13) still had improvements in rectal V70. In multiple regression analysis, greater postinjection reduction in V70 was associated with decreased relative postinjection plan conformity (P=.01). Reductions in V70 did not significantly vary by institution, despite significant interinstitutional variations in plan conformity. There were no significant relationships between reduction in V70 and the other characteristics analyzed. Conclusions: Injection of hydrogel into the prostate-rectal interface resulted in dose reductions to rectum for >90% of patients treated. Rectal sparing was statistically significant across a range of 10 to 75 Gy and was demonstrated within the presence of significant interinstitutional variability in plan conformity, target definitions, and injection results.« less

[Research on optimization of mathematical model of flow injection-hydride generation-atomic fluorescence spectrometry].

PubMed

Cui, Jian; Zhao, Xue-Hong; Wang, Yan; Xiao, Ya-Bing; Jiang, Xue-Hui; Dai, Li

2014-01-01

Flow injection-hydride generation-atomic fluorescence spectrometry was a widely used method in the industries of health, environmental, geological and metallurgical fields for the merit of high sensitivity, wide measurement range and fast analytical speed. However, optimization of this method was too difficult as there exist so many parameters affecting the sensitivity and broadening. Generally, the optimal conditions were sought through several experiments. The present paper proposed a mathematical model between the parameters and sensitivity/broadening coefficients using the law of conservation of mass according to the characteristics of hydride chemical reaction and the composition of the system, which was proved to be accurate as comparing the theoretical simulation and experimental results through the test of arsanilic acid standard solution. Finally, this paper has put a relation map between the parameters and sensitivity/broadening coefficients, and summarized that GLS volume, carrier solution flow rate and sample loop volume were the most factors affecting sensitivity and broadening coefficients. Optimizing these three factors with this relation map, the relative sensitivity was advanced by 2.9 times and relative broadening was reduced by 0.76 times. This model can provide a theoretical guidance for the optimization of the experimental conditions.

Potential Environmental Impacts of CO2 Storage in Sedimentary Basins: Results From the Frio Brine Test, Texas, USA

NASA Astrophysics Data System (ADS)

Kharaka, Y. K.; Cole, D. R.; Hovorka, S. D.; Phelps, T. J.; Nance, S.

2006-12-01

Deep saline aquifers in sedimentary basins, including depleted petroleum reservoirs, provide advantageous locations close to major anthropogenic sources of CO2 and potential capacity for the storage of huge volumes of this greenhouse gas. To investigate the potential for the long-term storage of CO2 in such aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick "C" sandstone section of the Frio Formation, a regional saline aquifer in the U.S. Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m updip showed a Na-Ca-Cl type brine with 93,000 mg/L TDS at near saturation with CH4 at reservoir conditions; gas analyses show CH4 comprised ~95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5 to 5.7), pronounced increases in alkalinity (100 to 3000 mg/L as HCO3) and in Fe (30 to 1100 mg/L), and significant shifts in the isotopic compositions of H2O, Sr, DIC, and CH4. These data coupled with geochemical modeling indicate rapid dissolution of minerals, especially calcite and iron oxyhydroxides caused by lowered pH (~3.0 initially) of the brine in contact with the injected supercritical CO2. These geochemical parameters, together with perfluorocarbon tracer gases (PFTs) proved effective in mapping the distribution and interactions of the injected CO2 in the Frio "C". They are being used to track the migration of the injected CO2 into the local shallow groundwater and into the overlying Frio "B", comprised of a 4-m-thick sandstone bed and separated from the "C" by ~15 m of shale, muddy sandstone and siltstone beds. Results obtained to date from the four monitoring groundwater wells perforated (26-29 m) in the Beaumont aquifer show some temporal chemical changes. These changes, however, are tentatively attributed to natural variations and recharge events caused by the construction of a mud pit at the site, and not to leakage through the Anahuac Formation, the regional cap rock comprised of thick (~80 m) and impermeable marine shale and mudstone beds. Data on brine and gas compositions of samples obtained from the Frio "B" 6 mo after injection show significant CO2 (2.9% compared with 0.3% CO2 in dissolved gas) migration into the "B" sandstone. Except for two PFT tracer gases explained by desorption, results of samples collected 15 mo after injection show no other indications of injected CO2 in the "B" sandstone. The initial presence of injected CO2 near the observation well shows migration through the intervening beds or more likely a leakage through the remedial cement around the casing of a 50- year old well. These results highlight the importance of investigating the integrity of cement seals, especially in nearby abandoned wells, prior to the injection of large quantities of reactive and buoyant CO2.

Numerical Simulation of nZVI at the Field Scale

NASA Astrophysics Data System (ADS)

Chowdhury, A. I.; Krol, M.; Sleep, B. E.; O'Carroll, D. M.

2014-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI mobility at the field-scale. In this study a three dimensional, three phase, finite difference numerical simulator (CompSim) was used to simulate nZVI and polymer transport in a variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the amount of nZVI delivered to the saturated and unsaturated zones as well as the phase of nZVI (i.e., attached or aqueous phase). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity as well as viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher volume of nZVI delivered more iron particles at a given distance; however, not necessarily to a greater distance proportionate to the increase in volume. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and the numerical simulator can be a valuable tool for optimum design of nZVI applications.

Optimizing detection of noble gas emission at a former UNE site: sample strategy, collection, and analysis

NASA Astrophysics Data System (ADS)

Kirkham, R.; Olsen, K.; Hayes, J. C.; Emer, D. F.

2013-12-01

Underground nuclear tests may be first detected by seismic or air samplers operated by the CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization). After initial detection of a suspicious event, member nations may call for an On-Site Inspection (OSI) that in part, will sample for localized releases of radioactive noble gases and particles. Although much of the commercially available equipment and methods used for surface and subsurface environmental sampling of gases can be used for an OSI scenario, on-site sampling conditions, required sampling volumes and establishment of background concentrations of noble gases require development of specialized methodologies. To facilitate development of sampling equipment and methodologies that address OSI sampling volume and detection objectives, and to collect information required for model development, a field test site was created at a former underground nuclear explosion site located in welded volcanic tuff. A mixture of SF-6, Xe127 and Ar37 was metered into 4400 m3 of air as it was injected into the top region of the UNE cavity. These tracers were expected to move towards the surface primarily in response to barometric pumping or through delayed cavity pressurization (accelerated transport to minimize source decay time). Sampling approaches compared during the field exercise included sampling at the soil surface, inside surface fractures, and at soil vapor extraction points at depths down to 2 m. Effectiveness of various sampling approaches and the results of tracer gas measurements will be presented.

Intra-articular administration of hyaluronic acid increases the volume of the hyaline cartilage regenerated in a large osteochondral defect by implantation of a double-network gel.

PubMed

Fukui, Takaaki; Kitamura, Nobuto; Kurokawa, Takayuki; Yokota, Masashi; Kondo, Eiji; Gong, Jian Ping; Yasuda, Kazunori

2014-04-01

Implantation of PAMPS/PDMAAm double-network (DN) gel can induce hyaline cartilage regeneration in the osteochondral defect. However, it is a problem that the volume of the regenerated cartilage tissue is gradually reduced at 12 weeks. This study investigated whether intra-articular administration of hyaluronic acid (HA) increases the volume of the cartilage regenerated with the DN gel at 12 weeks. A total of 48 rabbits were used in this study. A cylindrical osteochondral defect created in the bilateral femoral trochlea was treated with DN gel (Group DN) or left without any implantation (Group C). In both Groups, we injected 1.0 mL of HA in the left knee, and 1.0 mL of saline solution in the right knee. Quantitative histological evaluations were performed at 2, 4, and 12 weeks, and PCR analysis was performed at 2 and 4 weeks after surgery. In Group DN, the proteoglycan-rich area was significantly greater in the HA-injected knees than in the saline-injected knees at 12 weeks (P = 0.0247), and expression of type 2 collagen, aggrecan, and Sox9 mRNAs was significantly greater in the HA-injected knees than in the saline-injected knees at 2 weeks (P = 0.0475, P = 0.0257, P = 0.0222, respectively). The intra-articular administration of HA significantly enhanced these gene expression at 2 weeks and significantly increased the volume of the hyaline cartilage regenerated by implantation of a DN gel at 12 weeks. This information is important to develop an additional method to increase the volume of the hyaline cartilage tissue in a potential cartilage regeneration strategy using the DN gel.

A Technique for Thermal Desorption Analyses Suitable for Thermally-Labile, Volatile Compounds.

PubMed

Alborn, Hans T

2018-02-01

Many plant and insect interactions are governed by odors released by the plants or insects and there exists a continual need for new or improved methods to collect and identify these odors. Our group has for some time studied below-ground, plant-produced volatile signals affecting nematode and insect behavior. The research requires repeated sampling of volatiles of intact plant/soil systems in the laboratory as well as the field with the help of probes to minimize unwanted effects on the systems we are studying. After evaluating solid adsorbent filters with solvent extraction or solid phase micro extraction fiber sample collection, we found dynamic sampling of small air volumes on Tenax TA filters followed by thermal desorption sample introduction to be the most suitable analytical technique for our applications. Here we present the development and evaluation of a low-cost and relatively simple thermal desorption technique where a cold trap cooled with liquid carbon dioxide is added as an integral part of a splitless injector. Temperature gradient-based focusing and low thermal mass minimizes aerosol formation and eliminates the need for flash heating, resulting in low sample degradation comparable to solvent-based on-column injections. Additionally, since the presence of the cold trap does not affect normal splitless injections, on-the-fly switching between splitless and thermal desorption modes can be used for external standard quantification.

Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

PubMed

Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

2018-04-01

Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C 18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Role of Salivary Gland Scintigraphy in the Evaluation of Salivary Gland Dysfunction in Uncontrolled Type II Diabetic Patients.

PubMed

Senthilkumar, B; Sathasivasubramanian, S

2013-09-01

The aim of the present study was to evaluate the salivary gland dysfunction in patients with uncontrolled type II diabetes using salivary gland scintigraphy and then to compare these ratios with quantitative whole salivary secretion rates. Using a gamma camera (siemens-diacam) equipped with a low energy all-purpose collimator, 32 uncontrolled type II diabetic patients and 30 normal healthy patients were studied by injecting a radio isotope (technetium 99m pertechnetate) about 5 mCi was injected intravenously in to anticubital vein and the activity was measured for the 1(st), 20(th) and 40(th) min. At 20 min after injection, vitamin C chewable tablet was given to stimulate the secretion and continued until the end of the study period (40 min). Before scintigraphy, salivary sampling was carried out in both diabetic and normal individuals in a quiet room, saliva was allowed to accumulate and was expectorated into the collecting vessel approximately once a minute for 15 min and the volume was recorded as Unstimulated salivary flow rate and after 5 min break vitamin C chewable tablet was given to stimulate the secretion and the patient was asked to expectorate the saliva in the collecting vessel for 5 min. The expectorated volume was recorded as stimulated salivary flow rate. The mean of the measurements of scintigraphic ratio and salivary secretion rates were compared using the paired Student's t-test. The scintigraphic mean uptake and excretory ratio (ER) and the salivary flow rates were correlated. The result shows that there was a significant correlation between salivary flow rate and scintigraphic uptake and ER. However, statistically significant result could not be derived as it may be due to smaller sample size and marginal difference in the scintigraphic values between the groups. Salivary gland scintigraphy plays a significant role in the evaluation of salivary gland dysfunction. However, its role as an independent investigative procedure in the evaluation of salivary gland dysfunction requires a study with a larger sample size, may yield a statistical significant result and it can also act as an adjunct along with salivary flow rate procedure.

Contrast-enhanced magnetic resonance angiography: first-pass arterial enhancement as a function of gadolinium-chelate concentration, and the saline chaser volume and injection rate.

PubMed

Husarik, Daniela B; Bashir, Mustafa R; Weber, Paul W; Nichols, Eli B; Howle, Laurens E; Merkle, Elmar M; Nelson, Rendon C

2012-02-01

To evaluate the effect of the contrast medium (CM) concentration and the saline chaser volume and injection rate on first-pass aortic enhancement characteristics in contrast-enhanced magnetic resonance angiography using a physiologic flow phantom. Imaging was performed on a 3.0-T magnetic resonance system (MAGNETOM Trio, Siemens Healthcare Solutions, Inc, Erlangen, Germany) using a 2-dimensional fast low angle shot T1-weighted sequence (repetition time, 500 milliseconds; echo time, 1.23 milliseconds; flip angle, 8 degrees; 1 frame/s × 60 seconds). The following CM concentrations injected at 2 mL/s were used with 3 different contrast agents (gadolinium [Gd]-BOPTA, Gd-HP-DO3A, Gd-DTPA): 20 mL of undiluted CM (100%) and 80%, 40%, 20%, 10%, 5%, and 2.5% of the full amount, all diluted in saline to a volume of 20 mL to ensure equal bolus volume. The CM was followed by saline chasers of 20 to 60 mL injected at 2 mL/s and 6 mL/s. Aortic signal intensity (SI) was measured, and normalized SI versus time (SI/Tn) curves were generated. The maximal SI (SI(max)), bolus length, and areas under the SI/Tn curve were calculated. Decreasing the CM concentration from 100% to 40% resulted in a decrease of SI(max) to 86.1% (mean). Further decreasing the CM concentration to 2.5% decreased SI(max) to 5.1% (mean). Altering the saline chaser volume had no significant effect on SI(max). Increasing the saline chaser injection rate had little effect (mean increase, 2.2%) on SI(max) when using ≥40% of CM. There was a larger effect (mean increase, 19.6%) when ≤20% of CM were used. Bolus time length was significantly shorter (P < 0.001), and area under the SI/T(n) curve was significantly smaller (P < 0.01) for the CM protocols followed by a saline chaser injected at 6 mL/s compared with a saline chaser injected at 2 mL/s. With 40% of CM and a fast saline chaser, SImax close to that with undiluted CM can be achieved. An increased saline chaser injection rate has a more pronounced effect on aortic enhancement characteristics at lower CM concentrations than at higher CM concentrations.

Local complications after industrial liquid silicone injection: case series.

PubMed

Mello, Daniel Francisco; Gonçalves, Karen Chicol; Fraga, Murilo F; Perin, Luis Fernando; Helene, Américo

2013-01-01

To analyze a case series of patients who underwent injection of industrial liquid silicone in a clandestine manner and by unauthorized persons. We conducted a retrospective analysis of medical records of patients treated between September 2003 and December 2010. Data regarding gender, age, location and volume of silicone injected, time between application and clinical manifestations, complications, treatment and outcome were collected. Early manifestations were defined as occurring within 30 days of injection and late manifestations, the ones arising after this period. We treated 12 patients, eight were male, seven transsexuals. The volume injected ranged from 5 ml to 2000 ml, being unknown in three cases. The most often used injected sites were the thighs and buttocks. Eight patients had early manifestations, with inflammation and/or infection. Surgical debridement was necessary in five cases. Three patients with a history of injection in the breast region underwent adenomastectomy. There was one death due to refractory septic shock. The use of industrial liquid silicone should be completely contraindicated as a filling material and modification of body contouring, and may have serious complications, even death.

Porous structure and fluid partitioning in polyethylene cores from 3D X-ray microtomographic imaging.

PubMed

Prodanović, M; Lindquist, W B; Seright, R S

2006-06-01

Using oil-wet polyethylene core models, we present the development of robust throat finding techniques for the extraction, from X-ray microtomographic images, of a pore network description of porous media having porosity up to 50%. Measurements of volume, surface area, shape factor, and principal diameters are extracted for pores and area, shape factor and principal diameters for throats. We also present results on the partitioning of wetting and non-wetting phases in the pore space at fixed volume increments of the injected fluid during a complete cycle of drainage and imbibition. We compare these results with fixed fractional flow injection, where wetting and non-wetting phase are simultaneously injected at fixed volume ratio. Finally we demonstrate the ability to differentiate three fluid phases (oil, water, air) in the pore space.

The effect of intra-articular glucocorticosteroids and exercise on symptoms and bone marrow lesions in knee osteoarthritis: a secondary analysis of results from a randomized controlled trial.

PubMed

Nielsen, F K; Boesen, M; Jurik, A G; Bliddal, H; Nybing, J D; Ellegaard, K; Bartholdy, C; Bandak, E; Henriksen, M

2018-03-02

To evaluate if the relative volume of bone marrow lesions (BMLs) changed in patients with knee osteoarthritis (OA) during a therapeutic study. This study is a sub-study to a larger clinical trial which compared the clinical effects of intra-articular corticosteroid injection in knee OA to placebo injection, both given prior to exercise therapy. Clinical assessment using the Knee injury and Osteoarthritis Outcome Score (KOOS) and magnetic resonance imaging (MRI) examinations with BML assessments were performed at baseline and follow-up after 14 weeks and 26 weeks, respectively. The BML volume was determined using a computer assisted method focusing on participants with valid baseline and follow-up MRI examinations. Any changes in BML and KOOS were analyzed and investigated for associations. Fifty participants received steroid and placebo injection, respectively, of which 41 and 45 had complete MRI examinations at week 14, and 36 and 33 at week 26, respectively. All participants received 12 weeks of exercise. A significant change in relative BML volume was observed between the corticosteroid group and the placebo group after 14 weeks [-1.1% vs 2.7%; between-group difference, 3.8% (95% CI 0.5-7.0)] but not after 26 weeks [0.8% vs 1.6%; between-group difference, 0.8% (95% CI -2.8 to 4.4)]. No significant association was found between changes in relative BML volume and KOOS. Despite the statistically significant difference in BML volume at 14 weeks after corticosteroid injection and 12 weeks exercise therapy compared to placebo injection and exercise, there is very little evidence on a relationship between corticosteroids and BML volume. EudraCT number: 2012-002607-18. Copyright © 2018 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Particulate and microbial contamination in in-use admixed intravenous infusions.

PubMed

Yorioka, Katsuhiro; Oie, Shigeharu; Oomaki, Masafumi; Imamura, Akihisa; Kamiya, Akira

2006-11-01

We compared particulate and microbial contamination in residual solutions of peripheral intravenous admixtures after the termination of drip infusion between intravenous fluids admixed with glass ampoule drugs and those admixed with pre-filled syringe drugs. The mean number of particles>or=1.3 microm in diameter per 1 ml of residual solution was 758.4 for fluids (n=60) admixed with potassium chloride in a glass ampoule (20 ml volume), 158.6 for fluids (n=63) admixed with potassium chloride in a pre-filled syringe (20 ml volume), 736.5 for fluids (n=66) admixed with sodium chloride in a glass ampoule (20 ml volume), 179.2 for fluids (n=15) admixed with sodium chloride in a pre-filled syringe (20 ml volume), 1884.5 in fluids (n=30) admixed with dobutamine hydrochloride in 3 glass ampoules (5 ml volume), and 178.9 (n=10) in diluted dobutamine hydrochloride in pre-filled syringes (50 ml volume: For these samples alone, particulate and microbial contamination were evaluated in sealed products.) Thus, for potassium chloride or sodium chloride for injection, the number of particles>or=1.3 microm in diameter in the residual intravenous solution was significantly higher for fluids admixed with glass ampoule drugs than for those admixed with pre-filled syringe drugs (p<0.0001). For dobutamine hydrochloride for injection, the number of particles>or=1.3 microm in diameter in the residual intravenous solution was estimated to be higher for fluids admixed with its glass ampoule drug than for those admixed with its pre-filled syringe drug. Observation of the residual solutions of fluids admixed with potassium chloride, sodium chloride, or dobutamine hydrochloride in glass ampoules using an electron microscope with an X-ray analyzer showed glass fragments in each residual solution. Therefore, for the prevention of glass particle contamination in peripheral intravenous admixtures, the use of pre-filled syringe drugs may a useful method. No microbial contamination was observed in any of the residual solutions of 5 types of admixture.

Subcutaneous injection of liquid and foamed polidocanol: extravasation is not responsible for skin necrosis during reticular and spider vein sclerotherapy.

PubMed

Schuller-Petrović, S; Pavlović, M D; Neuhold, N; Brunner, F; Wölkart, G

2011-08-01

Cutaneous necrosis is one of the most annoying complications of reticular and spider vein sclerotherapy. The precise incidence of the complication is not known, although various sources reported incidence between 0.2% and 1.2%. Among a few mechanisms proposed to explain it, extravasation of the sclerosant into the perivascular tissue has been cited as the major cause. The aim of the experimental study in rats was to examine the potential of various concentrations and volumes of polidocanol in both liquid and foam forms to cause cutaneous necrosis after superficial subcutaneous injection. Twenty-four female Sprague Dawley rats were injected subcutaneously different concentrations (0.5%, 1%, 2% and 3%) of polidocanol as well as different preparations of polidocanol (liquid vs. foam) and volumes (0.1-0.5 mL). The animals were sacrificed 10 days after injections and biopsy specimens were obtained. Cutaneous necrosis was not seen at volumes <0.5 mL regardless of the concentration or form of polidocanol injected. Foam preparation was shown to be less potent in inducing necrosis with a minimal strength being 2% in comparison with the liquid form where 1% was sufficient to produce overt cutaneous necrosis. This experimental study shows that extravasation of polidocal in usual circumstances of sclerotherapy of spider and reticular veins cannot be a significant cause of cutaneous necrosis rarely observed in this setting. It is particularly true for the foamed polidocanol where 1% strength seems safe if injected extravascularly in volumes up to 0.5 mL. © 2010 The Authors. Journal of the European Academy of Dermatology and Venereology © 2010 European Academy of Dermatology and Venereology.

Equal volumes of undiluted nalbuphine and lidocaine and normal diluted saline prevents nalbuphine-induced injection pain.

PubMed

Wang, Fu-Yuan; Shen, Ya-Chun; Chen, Mao-Kai; Chau, Siu-Wah; Ku, Chia-Ling; Feng, Yu-Tung; Cheng, Kuang-I

2011-12-01

To determine if the intravenous co-administration of equal volumes of lidocaine and nalbuphine, with undiluted normal saline, prevents injection pain caused by nalbuphine. Eighty adult patients who were scheduled for minor surgeries under general anesthesia delivered via a laryngeal mask airway (LMA) were enrolled in this prospective, randomized, single-blind clinical trial. In the saline group (control) (n = 40), 1 mL (10 mg) nalbuphine was diluted with 9 mL normal saline. In the lidocaine group (experimental) (n = 40), 1 mL (10 mg) nalbuphine was diluted with 1 mL lidocaine (20 mg). The two respective nalbuphine solutions were injected into the cephalic vein at a rate of 20 mL/minute (0.33 mL/second). Pain scores were categorized into five grades. Pain responses upon intravenous injection of nalbuphine, site of cannulation, size of the catheter, and hemodynamic responses to nalbuphine were also recorded. Overall, the median pain score of patients in the lidocaine group was lower than that of the saline group (p < 0.001). In addition, the incidence of injection pain was lower in the lidocaine group than the saline group (2.5% vs. 30%, p = 0.001). A solution of equal volumes of lidocaine and nalbuphine can decrease intravenous nalbuphine-induced injection pain. Copyright © 2011. Published by Elsevier B.V.

Comments on Economides and Ehlig-Economides,"Sequestering carbon dioxide in a closed underground volume," SPE 124430, October 2009

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oldenburg, Curt; Pruess, Karsten; Birkholzer, Jens

The paper examines the pressure increase resulting from injection of CO2 into a 1D radial system with closed boundaries. The finding is that unacceptably high pressures are obtained when only 1% or less of the pore volume is occupied by injected CO2. These results are used to make the general conclusion that large-scale CCS is not feasible.

Effectiveness of Needleless Vial Adaptors and Blunt Cannulas for Drug Administration in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Hailey, M.; Bayuse, T.

2010-01-01

Fluid Isolation in the medication vial: Air/ fluid isolation maneuvers were used to move the medication to the septum end of vial. This isolation may be achieved in multiple ways based on the experience of the astronaut with fluid management in microgravity. If vial adaptors/blunt cannula or syringe assembly is inserted into the to vial before fluid isolation commences, the stability of this assembly should be considered in an effort to limit the risk of "slinging off" of the vial during isolation. Alternatively, fluid isolation can be performed prior to attaching the syringe/vial adaptor assembly. Terrestrial practices for medication withdrawal from a nonvented vial require injection of an equivalent amount of air as the expected medication volume prior to withdrawing liquid. In microgravity, this action is still valid, however the injection of additional air into the vial creates a multitude of micro bubbles and increases the volume of medication mixed with air that then must be withdrawn to achieve the desired drug volume in syringe. This practice is more likely to be required when using vials >30ml in size and injection volumes >10mL. It is felt that based on the microgravity flight, the practice of air injection is more of a hindrance than help.

Effects of epinephrine on lidocaine pharmacokinetics and blood volume in the dental pulp.

PubMed

Hashimoto, Shuichi; Yamashiro, Mikiko; Fujita, Kyohei; Yasuda, Asako; Sunada, Katsuhisa

2014-09-01

Epinephrine potentiates and prolongs the efficacy of local anesthetics by reducing blood flow. We investigated the effect of epinephrine on the pharmacokinetics of lidocaine and the pulpal blood volume after maxillary infiltration anesthesia in rats. We measured the (14)C-radioactivity and (14)C-distribution in the maxilla and the dental pulp after the injection of 2% (14)C-lidocaine with or without 10 μg/mL epinephrine (n = 7) into the palatine mucosa proximal to the first molar. The blood volume in the pulp was measured using (99m)Tc-pertechnetate (n = 5). When lidocaine was injected together with epinephrine, the lidocaine became widely distributed throughout the maxilla and was observed mainly in the first molar pulp. The lidocaine amount in the dental pulp at 10-60 minutes was more than 2 times higher than that after the injection of lidocaine alone. The relative pulpal blood volume after 20 minutes decreased to 63.1% of the value after the injection of lidocaine alone. We found that lidocaine had infiltrated into the molar pulp after infiltration anesthesia. Furthermore, our results suggested that epinephrine augmented the retention of lidocaine in the pulp. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

MACULAR CHOROIDAL VOLUME CHANGES AFTER INTRAVITREAL BEVACIZUMAB FOR EXUDATIVE AGE-RELATED MACULAR DEGENERATION.

PubMed

Palkovits, Stefan; Seidel, Gerald; Pertl, Laura; Malle, Eva M; Hausberger, Silke; Makk, Johanna; Singer, Christoph; Osterholt, Julia; Herzog, Sereina A; Haas, Anton; Weger, Martin

2017-12-01

To evaluate the effect of intravitreal bevacizumab on the macular choroidal volume and the subfoveal choroidal thickness in treatment naïve eyes with exudative age-related macular degeneration. The macular choroidal volume and the subfoveal choroidal thickness were measured using enhanced depth imaging optical coherence tomography. After a screening examination, each patient received 3 monthly intravitreal injections of 1.25 mg bevacizumab. One month after the third injection was a final assessment. Forty-seven patients with a mean age of 80 ± 6.4 years were included. The macular choroidal volume decreased significantly from median 4.1 mm (interquartile range 3.4-5.9) to median 3.9 mm (interquartile range 3.1-5.6) between the baseline and final examination (difference -0.46 mm, 95% confidence interval: -0.57 to 0.35, P < 0.001). Similarly, subfoveal choroidal thickness had decreased from 157.0 μm (interquartile range 116.0-244.5) at baseline to 139.0 μm (interquartile range 102.5-212.0) at the final examination (P < 0.001). Both parameters macular choroidal volume at baseline and subfoveal choroidal thickness at baseline were not associated with the response to treatment. The macular choroidal volume and the subfoveal choroidal thickness decreased significantly after 3 monthly bevacizumab injections for exudative age-related macular degeneration.

The 2014 Weld County, Colorado, Earthquakes: A developing case of induced seismicity?

NASA Astrophysics Data System (ADS)

Yeck, W. L.; Sheehan, A. F.; Weingarten, M.; Nakai, J.

2014-12-01

On June 1st 2014 (UTC), a M 3.2 earthquake occurred in Weld County, Colorado. Weld County is largely aseismic and this event was unexpected. There were no events in the ANSS Comprehensive Catalogue within 50 km of the earthquake. Weld County is the center of active oil and gas development, including many high-volume Class II wastewater injection wells. Injection wells have been linked to an increasing number of earthquakes throughout the US in recent years. Due to the lack of background seismicity in the area and the proximity of the earthquake to several injection wells, the University of Colorado requested seismometers from IRIS PASSCAL's Rapid Array Mobilization Program in order to study further seismicity. Seismic stations were deployed within 3 days of the June 1st event. We report on our ongoing findings from this deployment. To date, we have located 89 earthquakes and have detected over 600. These numbers continue to grow as we collect and analyze further data. Earthquake magnitudes remain small with only three earthquakes above M 2.0 recorded by our network, the largest of which was an M 2.6 earthquake on June 23rd 2014. Earthquakes locate in a small cluster (~2 km radius) centered near a high-volume injection well. This well operated at injection rates greater than 300,000 barrels/month since August 2013 and injects at a depth near the sediment-basement contact. Prior to our local deployment, the closest seismic station to the June 1st event was > 100 km away and therefore the evolution of seismicity prior the June 1st earthquake is poorly constrained. In order to better understand the temporal evolution of seismicity, we use match-filtering on data from these distant stations and find the earliest matching event on November 11th 2013. Due to the strong spatial and temporal correlation between these events and injection operations, we find it likely that these earthquakes are induced. In response to the ongoing seismicity near the well, the Colorado Oil and Gas Conservation Commission (COGCC) ordered the high-volume well shutdown for 20 days. The well has since restarted injection at lower rates, with the potential to increase injection rates over time. The shutdown and resumption of smaller injection volumes provides the unique opportunity to directly evaluate the seismicity's relationship to well operations.

Sulforaphane Modulates Joint Inflammation in a Murine Model of Complete Freund's Adjuvant-Induced Mono-Arthritis.

PubMed

Silva Rodrigues, João Francisco; Silva E Silva, Cristiane; França Muniz, Thayanne; de Aquino, Alana Fernanda; Neuza da Silva Nina, Larissa; Fialho Sousa, Nagila Caroline; Nascimento da Silva, Luis Claudio; de Souza, Breno Glaessner Gomes Fernandes; da Penha, Tatiana Aranha; Abreu-Silva, Ana Lúcia; de Sá, Joicy Cortez; Soares Fernandes, Elizabeth; Grisotto, Marcos Augusto Grigolin

2018-04-24

Rheumatoid arthritis (RA) is characterized by inflammation of one or more joints, and affects ~1% of the adult population worldwide. Sulforaphane (SFN) is a natural compound that has been suggested as an antioxidant. Here, SFN’s effects were evaluated in a murine mono-arthritis model. Mono-arthritis was induced in mice by a single intra-articular injection of Complete Freund’s Adjuvant (CFA-10 µg/joint, in 10 µL) into the ipsilateral joint. The contralateral joint received an equal volume of PBS. On the 4th day post-joint inflammation induction, animals received either SFN (10 mg/kg) or vehicle (3% DMSO in saline), intraperitoneally (i.p.), twice a day for 3 days. Joint swelling and secondary mechanical allodynia and hyperalgesia were evaluated over 7 days post-CFA. After this period, animals were culled and their blood and synovial fluid samples were collected for analysis of cell populations, cytokine release and thioredoxin reductase (TrxR) activity. Knee joint samples were also collected for histology. SFN reduced joint swelling and damage whilst increasing the recruitment of Ly6C⁺ and Ly6G⁺ cells to CFA-injected joints. SFN-treated animals presented down-regulation of CD11b and CD62L on synovial fluid Ly6G⁺ cells. Synovial fluid samples obtained from CFA-injected joints and plasma samples of SFN-treated mice presented higher levels of IL-6 and increased activity of TrxR, in comparison with controls. These results indicate that SFN reduces knee joint damage by modulating cell activation/migration to the joints, cytokine production and increasing the activity of TrxR, and therefore, may represent an alternative treatment to joint inflammation.

Achieving the full performance of highly efficient columns by optimizing conventional benchmark high-performance liquid chromatography instruments.

PubMed

Gritti, Fabrice; Sanchez, Carl A; Farkas, Tivadar; Guiochon, Georges

2010-04-30

A series of experiments and measurements demonstrate the importance of minimizing the extra-column band broadening contribution of the instrument used. The combination of several measures allowed the achievement of the full potential efficiency of three Kinetex-C(18) columns, using a conventional liquid chromatograph. The first measure consists in minimizing the extra-column volume of the instrument, without increasing much its back pressure contribution, by changing the needle seat volume, the inner diameter and length of the capillary connectors, and the volume of the detector cell of a standard instrument (Agilent 1100). The second measure consists in injecting a volume of weak eluent (less than half the elution strength of the mobile phase) right after the sample, before the sample had time to reach the column. Experimental results show that these changes could provide most of the resolution expected from the true column performance. After the changes were made, the resolutions of the 2.1 mm x 50 mm, 4.6 mm x 50 mm, and 4.6 mm x 100 mm Kinetex-C(18) columns for compounds having retention factors close to 1 were increased by about 180, 35, and 30%, respectively. The resolutions obtained are then similar to those measured with advanced instruments like the Agilent 1200, the Agilent 1290 Infinity HPLC, and the Acquity chromatographs. 2010 Elsevier B.V. All rights reserved.

A minimally invasive micro sampler for quantitative sampling with an ultrahigh-aspect-ratio microneedle and a PDMS actuator.

PubMed

Liu, Long; Wang, Yan; Yao, Jinyuan; Yang, Cuijun; Ding, Guifu

2016-08-01

This study describes a novel micro sampler consisting of an ultrahigh-aspect-ratio microneedle and a PDMS actuator. The microneedle was fabricated by a new method which introduced reshaped photoresist technology to form a flow channel inside. The microneedle includes two parts: shaft and pedestal. In this study, the shaft length is 1500 μm with a 45° taper angle on the tip and pedestal is 1000 μm. Besides, the shaft and pedestal are connected by an arc connection structure with a length of 600 μm. The microneedles have sufficient mechanical strength to insert into skin with a wide safety margin which was proved by mechanics tests. Moreover, a PDMS actuator with a chamber inside was designed and fabricated in this study. The chamber, acting as a reservoir in sampling process as well as providing power, was optimized by finite element analysis (FEA) to decrease dead volume and improve sampling precision. The micro sampler just needs finger press to activate the sampling process as well as used for quantitative micro injection to some extent. And a volume of 31.5 ± 0.8 μl blood was successfully sampled from the ear artery of a rabbit. This micro sampler is suitable for micro sampling for diagnose or therapy in biomedical field.

Variable volume combustor with pre-nozzle fuel injection system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keener, Christopher Paul; Johnson, Thomas Edward; McConnaughhay, Johnie Franklin

The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of fuel nozzles, a pre-nozzle fuel injection system supporting the fuel nozzles, and a linear actuator to maneuver the fuel nozzles and the pre-nozzle fuel injection system.

Development of In Vitro Isolated Perfused Porcine Skin Flaps for Study of Percutaneous Absorption of Xenobiotics

DTIC Science & Technology

1986-11-01

prepared within 1 week of use. Pigs were weighed and anesthetized by intramuscular injection of 4 mg/kg xylazine (Rompun; Miles/Bayvet, Shawnee, KS) and...vein and blood samples (1-ml each) were taken at 15, 30, 45, 60, and 90 min and at 2, 3, 4, 6, 8, 12, 24, and 48 hr for pharmacokinetic disposition...separately. A two-compartment pharmacokinetic model was fitted to the )b1ood and plasma concentrations and clearance (Cl), volume of distribution (Vc

Fetal blood drawing.

PubMed

Hobbins, J C; Mahoney, M J

1975-07-19

A small sample of fetal blood suitable for studies of haemoglobin synthesis was obtained from a placental vessel under endoscopic visualisation in 23 of 26 patients in whom the procedure was attempted prior to second-trimester abortion. Fetal blood loss, calculated in 23 cases, was between 0-2 ml. and 2-5 ml., and fetal blood-volume depletion varied from 0-5% to 15%. No short-term ill-effects were demonstrated in mother or fetus in any of 16 patients in whom the injection of aborti-facient was postponed for between 16 and 24 hours after the procedure.

Epidural migration of new methylene blue in 0.9% sodium chloride solution or 2% mepivacaine solution following injection into the first intercoccygeal space in foal cadavers and anesthetized foals undergoing laparoscopy.

PubMed

Lansdowne, Jennifer L; Kerr, Carolyn L; Bouré, Ludovic P; Pearce, Simon G

2005-08-01

To determine the relationship between epidural cranial migration and injectate volume of an isotonic solution containing dye in laterally recumbent foal cadavers and evaluate the cranial migration and dermatome analgesia of an epidural dye solution during conditions of laparoscopy in foals. 19 foal cadavers and 8 pony foals. Foal cadavers received an epidural injection of dye solution (0.05, 0.1, 0.15, or 0.2 mL/kg) containing 1.2 mg of new methylene blue (NMB)/mL of saline (0.9% NaCl) solution. Length of the dye column and number of intervertebral spaces cranial and caudal to the injection site were measured. Anesthetized foals received an epidural injection of dye solution (0.2 mL/kg) containing saline solution or 2% mepivacaine. Foals were placed in a 100 head-down position, and pneumoperitoneum was induced. Dermatome analgesia was determined by use of a described electrical stimulus technique. Foals were euthanatized, and length of the dye column was measured. Epidural cranial migration of dye solution in foal cadavers increased with increasing volume injected. No significant difference was found in epidural cranial migration of a dye solution (0.2 mL/kg) between anesthetized foals undergoing conditions of laparoscopy and foal cadavers in lateral recumbency. Further craniad migration of the dye column occurred than indicated by dermatome analgesia. Epidural cranial migration increases with volume of injectate. On the basis of dermatome analgesia, an epidural injection of 2% mepivacaine (0.2 mL/kg) alone provides analgesia up to at least the caudal thoracic dermatome and could permit caudal laparoscopic surgical procedures in foals.

Improved hydrostatic pressure sample injection by tilting the microchip towards the disposable miniaturized CE device.

PubMed

Wang, Wei; Zhou, Fang; Zhao, Liang; Zhang, Jian-Rong; Zhu, Jun-Jie

2008-02-01

A simple method of hydrostatic pressure sample injection towards a disposable microchip CE device was developed. The liquid level in the sample reservoir was higher than that in the sample waste reservoir (SWR) by tilting microchip and hydrostatic pressure was generated, the sample was driven to pass through injection channel into SWR. After sample loading, the microchip was levelled for separation under applied high separation voltage. Effects of tilted angle, initial liquid height and injection duration on electrophoresis were investigated. With enough injection duration, the injection result was little affected by tilted angle and initial liquid heights in the reservoirs. Injection duration for obtaining a stable sample plug was mainly dependent on the tilted angle rather than the initial height of liquid. Experimental results were consistent with theoretical prediction. Fluorescence observation and electrochemical detection of dopamine and catechol were employed to verify the feasibility of tilted microchip hydrostatic pressure injection. Good reproducibility of this injection method was obtained. Because the instrumentation was simplified and no additional hardware was needed in this technology, the proposed method would be potentially useful in disposable devices.

A Comparative Study of Drug Delivery Methods Targeted to the Mouse Inner Ear: Bullostomy Versus Transtympanic Injection

PubMed Central

Cediel, Rafael; Celaya, Adelaida M.; Lassaletta, Luis; Varela-Nieto, Isabel; Contreras, Julio

2017-01-01

We present two minimally invasive microsurgical techniques in rodents for specific drug delivery into the middle ear so that it may reach the inner ear. The first procedure consists of perforation of the tympanic bulla, termed bullostomy; the second one is a transtympanic injection. Both emulate human clinical intratympanic procedures. Chitosan-glycerophosphate (CGP) and Ringer´s Lactate buffer (RL) were used as biocompatible vehicles for local drug delivery. CGP is a nontoxic biodegradable polymer widely used in pharmaceutical applications. It is a viscous liquid at RT but it congeals to a semi solid phase at body temperature. RL is an isotonic solution used for intravenous administrations in humans. A small volume of this vehicle is precisely placed on the Round Window (RW) niche by means of a bullostomy. A transtympanic injection fills the middle ear and allows less control but broader access to the inner ear. The safety profiles of both techniques were studied and compared by using functional and morphological tests. Hearing was evaluated by registering the Auditory Brainstem Response (ABR) before and several times after microsurgery. The cytoarchitecture and preservation level of cochlear structures were studied by conventional histological techniques in paraformaldehyde-fixed and decalcified cochlear samples. In parallel, unfixed cochlear samples were taken and immediately frozen to analyze gene expression profiles of inflammatory markers by quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR). Both procedures are suitable as drug delivery methods into the mouse middle ear, although transtympanic injection proved to be less invasive compared to bullostomy. PMID:28362376

Pain and efficacy rating of a microprocessor-controlled metered injection system for local anaesthesia in minor hand surgery.

PubMed

Nimigan, André S; Gan, Bing Siang

2011-01-01

Purpose. Little attention has been given to syringe design and local anaesthetic administration methods. A microprocessor-controlled anaesthetic delivery device has become available that may minimize discomfort during injection. The purpose of this study was to document the pain experience associated with the use of this system and to compare it with use of a conventional syringe. Methods. A prospective, randomized clinical trial was designed. 40 patients undergoing carpal tunnel release were block randomized according to sex into a two groups: a traditional syringe group and a microprocessor-controlled device group. The primary outcome measure was surgical pain and local anaesthetic administration pain. Secondary outcomes included volume of anaesthetic used and injection time. Results. Analysis showed that equivalent anaesthesia was achieved in the microprocessor-controlled group despite using a significantly lower volume of local anaesthetic (P = .0002). This same group, however, has significantly longer injection times (P < .0001). Pain during the injection process or during surgery was not different between the two groups. Conclusions. This RCT comparing traditional and microprocessor controlled methods of administering local anaesthetic showed similar levels of discomfort in both groups. While the microprocessor-controlled group used less volume, the total time for the administration was significantly greater.

Simultaneous Determination of Fluid Shifts during Thermal Stress in a Small Animal Model,

DTIC Science & Technology

1985-09-01

extracellular fluid voitmie (BCF) was measured using a single injection c- inulin , technique, and plasma voilme (PV) was determined by ca.rdio--yreen dye...using tritiated water, extracell1ular fluid volume (ECF) was measured using a single injection C- inulin technique, and plasma volume (PV) was...space. However, inulin (10) has several advantages over the aforementioned because it Is not metabolized, stored, or incorporated by cells or

On the feasibility to conduct gradient liquid chromatography separations in narrow-bore columns at pressures up to 2000bar.

PubMed

De Pauw, Ruben; Swier, Tim; Degreef, Bart; Desmet, Gert; Broeckhoven, Ken

2016-11-18

The limits in operating pressures are extended for narrow-bore columns in gradient elution up to 2000bar. As the required pumps for these pressures are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition gradient, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and gradient elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column. This system consists out of 5 dual on/off valves and two large volume loops in which the gradient and equilibration volume of initial mobile phase are loaded by a commercial liquid chromatography pump. The loops are then flushed toward the column at extreme pressures. The mobile phase delivery and injection system is first evaluated in isocratic elution and shows a comparable performance to a state-of-the-art commercial flow-through-needle injector but with twice the pressure rating. Distortion of the loaded gradient by dispersion in the gradient storage loop is studied. The effect of the most important parameters (such as flow rate, pressure and gradient steepness) is experimentally investigated. Different gradient steepnesses and volumes can be applied at different flow rates and operating pressures with a good repeatability. Due to the isobaric operation of the pumps, the gradient is monitored in real-time by a mass flow meter installed at the detector outlet. The chromatograms are then converted from time to volume-base. A separation of a 19-compound sample is performed on a 300×2.1mm column at 1000bar and on a 600×2.1mm column at 2000bar. The peak capacity was found to increase from 141 to 199 and thus scales with L as is predicted by theory. This allows to conclude that the inlet pressure for narrow-bore columns in gradient elution can be increased up to 2000bar without fundamental pressure-induced limitations. Copyright © 2016 Elsevier B.V. All rights reserved.

Rhesus Cochlear and Vestibular Functions Are Preserved After Inner Ear Injection of Saline Volume Sufficient for Gene Therapy Delivery.

PubMed

Dai, Chenkai; Lehar, Mohamed; Sun, Daniel Q; Rvt, Lani Swarthout; Carey, John P; MacLachlan, Tim; Brough, Doug; Staecker, Hinrich; Della Santina, Alexandra M; Hullar, Timothy E; Della Santina, Charles C

2017-08-01

Sensorineural losses of hearing and vestibular sensation due to hair cell dysfunction are among the most common disabilities. Recent preclinical research demonstrates that treatment of the inner ear with a variety of compounds, including gene therapy agents, may elicit regeneration and/or repair of hair cells in animals exposed to ototoxic medications or other insults to the inner ear. Delivery of gene therapy may also offer a means for treatment of hereditary hearing loss. However, injection of a fluid volume sufficient to deliver an adequate dose of a pharmacologic agent could, in theory, cause inner ear trauma that compromises functional outcome. The primary goal of the present study was to assess that risk in rhesus monkeys, which closely approximates humans with regard to middle and inner ear anatomy. Secondary goals were to identify the best delivery route into the primate ear from among two common surgical approaches (i.e., via an oval window stapedotomy and via the round window) and to determine the relative volumes of rhesus, rodent, and human labyrinths for extrapolation of results to other species. We measured hearing and vestibular functions before and 2, 4, and 8 weeks after unilateral injection of phosphate-buffered saline vehicle (PBSV) into the perilymphatic space of normal rhesus monkeys at volumes sufficient to deliver an atoh1 gene therapy vector. To isolate effects of injection, PBSV without vector was used. Assays included behavioral observation, auditory brainstem responses, distortion product otoacoustic emissions, and scleral coil measurement of vestibulo-ocular reflexes during whole-body rotation in darkness. Three groups (N = 3 each) were studied. Group A received a 10 μL transmastoid/trans-stapes injection via a laser stapedotomy. Group B received a 10 μL transmastoid/trans-round window injection. Group C received a 30 μL transmastoid/trans-round window injection. We also measured inner ear fluid space volume via 3D reconstruction of computed tomography (CT) images of adult C57BL6 mouse, rat, rhesus macaque, and human temporal bones (N = 3 each). Injection was well tolerated by all animals, with eight of nine exhibiting no signs of disequilibrium and one animal exhibiting transient disequilibrium that resolved spontaneously by 24 h after surgery. Physiologic results at the final, 8-week post-injection measurement showed that injection was well tolerated. Compared to its pretreatment values, no treated ear's ABR threshold had worsened by more than 5 dB at any stimulus frequency; distortion product otoacoustic emissions remained detectable above the noise floor for every treated ear (mean, SD and maximum deviation from baseline: -1.3, 9.0, and -18 dB, respectively); and no animal exhibited a reduction of more than 3 % in vestibulo-ocular reflex gain during high-acceleration, whole-body, passive yaw rotations in darkness toward the treated side. All control ears and all operated ears with definite histologic evidence of injection through the intended site showed similar findings, with intact hair cells in all five inner ear sensory epithelia and intact auditory/vestibular neurons. The relative volumes of mouse, rat, rhesus, and human inner ears as measured by CT were (mean ± SD) 2.5 ± 0.1, 5.5 ± 0.4, 59.4 ± 4.7 and 191.1 ± 4.7 μL. These results indicate that injection of PBSV at volumes sufficient for gene therapy delivery can be accomplished without destruction of inner ear structures required for hearing and vestibular sensation.

Ultrasound-guided injection for MR arthrography of the hip: comparison of two different techniques.

PubMed

Kantarci, Fatih; Ozbayrak, Mustafa; Gulsen, Fatih; Gencturk, Mert; Botanlioglu, Huseyin; Mihmanli, Ismail

2013-01-01

The purpose of this study was to prospectively evaluate the two different ultrasound-guided injection techniques for MR arthrography of the hip. Fifty-nine consecutive patients (21 men, 38 women) referred for MR arthrographies of the hip were prospectively included in the study. Three patients underwent bilateral MR arthrography. The two injection techniques were quantitatively and qualitatively compared. Quantitative analysis was performed by the comparison of injected contrast material volume into the hip joint. Qualitative analysis was performed with regard to extraarticular leakage of contrast material into the soft tissues. Extraarticular leakage of contrast material was graded as none, minimal, moderate, or severe according to the MR images. Each patient rated discomfort after the procedure using a visual analogue scale (VAS). The injected contrast material volume was less in femoral head puncture technique (mean 8.9 ± 3.4 ml) when compared to femoral neck puncture technique (mean 11.2 ± 2.9 ml) (p < 0.05). The chi-squared test showed significantly more contrast leakage by femoral head puncture technique (p < 0.05). Statistical analysis showed no difference between the head and neck puncture groups in terms of feeling of pain (p = 0.744) or in the body mass index (p = 0.658) of the patients. The femoral neck injection technique provides high intraarticular contrast volume and produces less extraarticular contrast leakage than the femoral head injection technique when US guidance is used for MR arthrography of the hip.

Interactions and exchange of CO2 and H2O in coals: an investigation by low-field NMR relaxation

NASA Astrophysics Data System (ADS)

Sun, Xiaoxiao; Yao, Yanbin; Liu, Dameng; Elsworth, Derek; Pan, Zhejun

2016-01-01

The mechanisms by which CO2 and water interact in coal remain unclear and these are key questions for understanding ECBM processes and defining the long-term behaviour of injected CO2. In our experiments, we injected helium/CO2 to displace water in eight water-saturated samples. We used low-field NMR relaxation to investigate CO2 and water interactions in these coals across a variety of time-scales. The injection of helium did not change the T2 spectra of the coals. In contrast, the T2 spectra peaks of micro-capillary water gradually decreased and those of macro-capillary and bulk water increased with time after the injection of CO2. We assume that the CO2 diffuses through and/or dissolves into the capillary water to access the coal matrix interior, which promotes desorption of water molecules from the surfaces of coal micropores and mesopores. The replaced water mass is mainly related to the Langmuir adsorption volume of CO2 and increases as the CO2 adsorption capacity increases. Other factors, such as mineral composition, temperature and pressure, also influence the effective exchange between water and CO2. Finally, we built a quantified model to evaluate the efficiency of water replacement by CO2 injection with respect to temperature and pressure.

Interactions and exchange of CO2 and H2O in coals: an investigation by low-field NMR relaxation.

PubMed

Sun, Xiaoxiao; Yao, Yanbin; Liu, Dameng; Elsworth, Derek; Pan, Zhejun

2016-01-28

The mechanisms by which CO2 and water interact in coal remain unclear and these are key questions for understanding ECBM processes and defining the long-term behaviour of injected CO2. In our experiments, we injected helium/CO2 to displace water in eight water-saturated samples. We used low-field NMR relaxation to investigate CO2 and water interactions in these coals across a variety of time-scales. The injection of helium did not change the T2 spectra of the coals. In contrast, the T2 spectra peaks of micro-capillary water gradually decreased and those of macro-capillary and bulk water increased with time after the injection of CO2. We assume that the CO2 diffuses through and/or dissolves into the capillary water to access the coal matrix interior, which promotes desorption of water molecules from the surfaces of coal micropores and mesopores. The replaced water mass is mainly related to the Langmuir adsorption volume of CO2 and increases as the CO2 adsorption capacity increases. Other factors, such as mineral composition, temperature and pressure, also influence the effective exchange between water and CO2. Finally, we built a quantified model to evaluate the efficiency of water replacement by CO2 injection with respect to temperature and pressure.

Interactions and exchange of CO2 and H2O in coals: an investigation by low-field NMR relaxation

PubMed Central

Sun, Xiaoxiao; Yao, Yanbin; Liu, Dameng; Elsworth, Derek; Pan, Zhejun

2016-01-01

The mechanisms by which CO2 and water interact in coal remain unclear and these are key questions for understanding ECBM processes and defining the long-term behaviour of injected CO2. In our experiments, we injected helium/CO2 to displace water in eight water-saturated samples. We used low-field NMR relaxation to investigate CO2 and water interactions in these coals across a variety of time-scales. The injection of helium did not change the T2 spectra of the coals. In contrast, the T2 spectra peaks of micro-capillary water gradually decreased and those of macro-capillary and bulk water increased with time after the injection of CO2. We assume that the CO2 diffuses through and/or dissolves into the capillary water to access the coal matrix interior, which promotes desorption of water molecules from the surfaces of coal micropores and mesopores. The replaced water mass is mainly related to the Langmuir adsorption volume of CO2 and increases as the CO2 adsorption capacity increases. Other factors, such as mineral composition, temperature and pressure, also influence the effective exchange between water and CO2. Finally, we built a quantified model to evaluate the efficiency of water replacement by CO2 injection with respect to temperature and pressure. PMID:26817784

EXPERIMENTAL INVESTIGATION OF PIC FORMATION IN ...

EPA Pesticide Factsheets

The report gives results of experiments to determine the effect of flame zone temperature on gas-phase flame formation and destruction of products of incomplete combustion (PICS) during dichlorodi-fluoromethane (CFC-12) incineration. The effect of water injection into the flame zone was also studied. Tests involved burning CFC-12 in a propane gas flame. Combustion gas samples were taken and analyzed for volatile organic compounds as well as polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF). CDD/PCDF were not detected at baseline operating conditions (1204 C and 9.3% CFC-12 by volume in fuel). Low levels of PCDD/ PCDF were detected in the combustion gas at a lower temperature (913 C). Poor combustion conditions producing smoke and soot may have contributed to the formation of PCDD/PCDF. Low levels of PCC/PCDF were also detected at the lower temperature with water injection into the flame zone. lame zone water injection may have a reducing effect on PCDD/PCDF formation during CFC-12 incineration. alogenated PICs (including chloromethane, vinyl chloride, CFC-11, dichloroethane, chloroform, trichloroethane, chlorobenzene, dichloropropene, carbon tetrachloride, methylene chloride, and tetrachloroethane) were detected during CFC-12 incineration. Information.

Multiscale Analysis of Soil Porosity from Hg Injection Curves in Soils from Minas Gerais, Brazil

NASA Astrophysics Data System (ADS)

Vidal Vázquez, E.; Miranda, J. G. V.; Paz-Ferreiro, J.

2012-04-01

The soil pore space is a continuum extremely variable in size, including structures smaller than nanometres and as large as macropores or cracks with millimetres or even centimetres size. Pore size distributions (PSDs) affects important soil functions, such as transmission and storage of water, and root growth. Direct and indirect measurements of PSDs are currently used to characterize soil structure. Mercury injection porosimetry is useful for assessing equivalent pore size diameters in the range from about 0,5 nm to 100 μm. Here, the multifractal formalism was employed to describe Hg injection curves measured in duplicate samples collected on 54 horizons from 19 profiles in Minas Gerais state, Brazil. Ten of the studied profiles were classified as Ferralsols (Latosols, Oxisols). Besides these, other wide different soil groups were sampled, including Nitisol, Acrisol, Alisol, Luvisol, Planosol, Cambisol, Andosol and Leptosol. Clay content varied from 4 to 86% and pore volume in the range from 100 to 0.005 μm was between 5.52 a 53.76 cm3100g-1. All the horizons taken on Ferralsols and Nitisols as well as in Bt argic horizons from Acrisol Alisol, Luvisol and Planosol clearly showed a bimodal pore size distribution. Pore volume in the range from 100 to 0.005 μm and microporosity (0,2-0.005 μm) showed a significant relationship with clay content an Al2O3. All the Hg injection data sets studied soil showed remarkably good scaling trends and could be fitted reasonably well with multifractal models. The capacity dimensions, D0, was not significantly different from the Euclidean dimension. The entropy dimension, D1, varied from 0.590 to 0.946 , whereas the Hölder exponent of order zero, α0was between 1.027 and 1.451, and these two parameters showed a lineal negatives relationship, as expected. The highest D1 values, ranging from 0.913 to 0.980, were obtained for the Leptosol, whereas the lowest D1 values, ranging from 0.641 to 0.766 corresponded to the Nitisol. This results reflect that most of the measure concentrated in a small size domain for the horizons sampled from the Nitisol, whereas for the Leptosol the measure was more evenly distributed. In general, multifractal indices have been found to be useful for assessing differences in pore size distributions of the studied soil types.

Intratympanic Iodine Contrast Injection Diffuses Across the Round Window Membrane Allowing for Perilymphatic CT Volume Acquisition Imaging.

PubMed

Abt, Nicholas B; Lehar, Mohamed; Guajardo, Carolina Trevino; Penninger, Richard T; Ward, Bryan K; Pearl, Monica S; Carey, John P

2016-04-01

Whether the round window membrane (RWM) is permeable to iodine-based contrast agents (IBCA) is unknown; therefore, our goal was to determine if IBCAs could diffuse through the RWM using CT volume acquisition imaging. Imaging of hydrops in the living human ear has attracted recent interest. Intratympanic (IT) injection has shown gadolinium's ability to diffuse through the RWM, enhancing the perilymphatic space. Four unfixed human cadaver temporal bones underwent intratympanic IBCA injection using three sequentially studied methods. The first method was direct IT injection. The second method used direct RWM visualization via tympanomeatal flap for IBCA-soaked absorbable gelatin pledget placement. In the third method, the middle ear was filled with contrast after flap elevation. Volume acquisition CT images were obtained immediately postexposure, and at 1-, 6-, and 24-hour intervals. Postprocessing was accomplished using color ramping and subtraction imaging. After the third method, positive RWM and perilymphatic enhancement were observed with endolymph sparing. Gray scale and color ramp multiplanar reconstructions displayed increased signal within the cochlea compared with precontrast imaging. The cochlea was measured for attenuation differences compared with pure water, revealing a preinjection average of -1,103 HU and a postinjection average of 338 HU. Subtraction imaging shows enhancement remaining within the cochlear space, Eustachian tube, middle ear epithelial lining, and mastoid. Iohexol iodine contrast is able to diffuse across the RWM. Volume acquisition CT imaging was able to detect perilymphatic enhancement at 0.5-mm slice thickness. The clinical application of IBCA IT injection seems promising but requires further safety studies.

DNP System Output Volume Reduction Using Inert Fluids

PubMed Central

Peterson, Eric T; Gordon, Jeremy W; Erickson, Matthew G; Fain, Sean B; Rowland, Ian J

2011-01-01

Purpose To present a method for significantly increasing the concentration of a hyperpolarized compound produced by a commercial DNP polarizer, enabling the polarization process to be more suitable for pre-clinical applications. Materials and Methods Using a HyperSense® DNP polarizer, we have investigated the combined use of perfluorocarbon and water to warm and dissolve the hyperpolarized material from the polarization temperature of 1.4 K to produce material at temperatures suitable for injection. Results By replacing 75% of the water in the dissolution volume with a chemically and biologically inert liquid that is immiscible with water, the injection volume can be reduced fourfold Rapid separation of the water and perfluorocarbon mixture enables the aqueous layer containing polarized material to be easily and rapidly collected. Conclusion The approach provides a significantly increased concentration of compound in a volume for injection that is more appropriate for small animal studies. This is demonstrated for 13C labeled pyruvic acid and 13C labeled succinate, but may be applied to the majority of nuclei and compounds hyperpolarized by the DNP method. PMID:21448970

Ultrasound-Assisted Emulsification Microextraction Based on Solidification Floating Organic Drop Trace Amounts of Manganese Prior to Graphite Furnace Atomic Absorption Spectrometry Determination

PubMed Central

Mohadesi, Alireza; Falahnejad, Masoumeh

2012-01-01

In the present study, an ultrasound-assisted emulsification microextraction based on solidification floating organic drop method is described for preconcentration of trace amounts of Mn (II). 2-(5-Bromo-2-pyridylazo)-5 diethylaminophenol was added to a solution of Mn+2 at ph = 10.0. After this, 1-undecanol was added to the solution as an extraction solvent, and solution was stirred. Several factors influencing the microextraction efficiency, such as pH, the amount of chelating agent, nature and volume of extraction solvent, the volume of sample solution, stirring rate, and extraction time were investigated and optimized. Then sample vial was cooled by inserting into an ice bath, and the solidified was transferred into a suitable vial for immediate melting. Finally the sample was injected into a graphite furnace atomic absorption spectrometry. Under the optimum condition the linear dynamic range was 0.50–10.0 ng mL−1 with a correlation coefficient of 0.9926, and the detection limit of 0.3 ng mL−1 was obtained. The enrichment factor was 160. The proposed method was successfully applied for separation and determination of manganese in sea, rain, tap, and river water samples. PMID:22645504

A Simple Carbon Dioxide Injection System for Photosynthetic Studies 12

PubMed Central

Oliver, David J.; Cameron, Stewart I.; Schaedle, Michail

1974-01-01

A simple carbon dioxide injection system has been developed for the maintenance of CO2 concentrations in semiclosed cuvette systems suitable for photosynthesis and gaseous pollutant studies. The device injects small volumes of pure carbon dioxide into the cuvette in response to a signal from an infrared gas analyzer. PMID:16658944

Induced Earthquakes Are Not All Alike: Examples from Texas Since 2008 (Invited)

NASA Astrophysics Data System (ADS)

Frohlich, C.

2013-12-01

The EarthScope Transportable Array passed through Texas between 2008 and 2011, providing an opportunity to identify and accurately locate earthquakes near and/or within oil/gas fields and injection waste disposal operations. In five widely separated geographical locations, the results suggest seismic activity may be induced/triggered. However, the different regions exhibit different relationships between injection/production operations and seismic activity: In the Barnett Shale of northeast Texas, small earthquakes occurred only near higher-volume (volume rate > 150,000 BWPM) injection disposal wells. These included widely reported earthquakes occurring near Dallas-Fort Worth and Cleburne in 2008 and 2009. Near Alice in south Texas, M3.9 earthquakes occurred in 1997 and 2010 on the boundary of the Stratton Field, which had been highly productive for both oil and gas since the 1950's. Both earthquakes occurred during an era of net declining production, but their focal depths and location at the field boundary suggest an association with production activity. In the Eagle Ford of south central Texas, earthquakes occurred near wells following significant increases in extraction (water+produced oil) volumes as well as injection. The largest earthquake, the M4.8 Fashing earthquake of 20 October 2011, occurred after significant increases in extraction. In the Cogdell Field near Snyder (west Texas), a sequence of earthquakes beginning in 2006 followed significant increases in the injection of CO2 at nearby wells. The largest with M4.4 occurred on 11 September 2011. This is the largest known earthquake possibly attributable to CO2 injection. Near Timpson in east Texas a sequence of earthquakes beginning in 2008, including an M4.8 earthquake on 17 May 2012, occurred within three km of two high-volume injection disposal wells that had begun operation in 2007. These were the first known earthquakes at this location. In summary, the observations find possible induced/triggered earthquakes associated with recent increases in injection, recent increases in extraction, with CO2 injection, and with declining production. In all areas, during the 2008-2011 period there were no earthquakes occurring near vast majority of extraction/production wells; thus, the principal puzzle is why these activities sometimes induce seismicity and sometimes do not.

Direct Measurement of Trace Elemental Mercury in Hydrocarbon Matrices by Gas Chromatography with Ultraviolet Photometric Detection.

PubMed

Gras, Ronda; Luong, Jim; Shellie, Robert A

2015-11-17

We introduce a technique for the direct measurement of elemental mercury in light hydrocarbons such as natural gas. We determined elemental mercury at the parts-per-trillion level with high precision [<3% RSD (n = 20 manual injection)] using gas chromatography with ultraviolet photometric detection (GC-UV) at 254 nm. Our approach requires a small sample volume (1 mL) and does not rely on any form of sample preconcentration. The GC-UV separation employs an inert divinylbenzene porous layer open tubular column set to separate mercury from other components in the sample matrix. We incorporated a 10-port gas-sampling valve in the GC-UV system, which enables automated sampling, as well as back flushing capability to enhance system cleanliness and sample throughput. Total analysis time is <2 min, and the procedure is linear over a range of 2-83 μg/m(3) [correlation coefficient of R(2) = 0.998] with a measured recovery of >98% over this range.

Determination of scandium in acid mine drainage by ICP-OES with flow injection on-line preconcentration using oxidized multiwalled carbon nanotubes.

PubMed

Jerez, Javier; Isaguirre, Andrea C; Bazán, Cristian; Martinez, Luis D; Cerutti, Soledad

2014-06-01

An on-line scandium preconcentration and determination system implemented with inductively coupled plasma optical emission spectrometry associated with flow injection was studied. Trace amounts of scandium were preconcentrated by sorption on a minicolumn packed with oxidized multiwalled carbon nanotubes, at pH 1.5. The retained analyte was removed from the minicolumn with 30% (v/v) nitric acid. A total enrichment factor of 225-fold was obtained within a preconcentration time of 300 s (for a 25 mL sample volume). The overall time required for preconcentration and elution of 25 mL of sample was about 6 min; the throughput was about 10 samples per hour. The value of the detection limit was 4 ng L(-1) and the precision for 10 replicate determinations at 100 ng L(-1) Sc level was 5% relative standard deviation, calculated from the peak heights obtained. The calibration graph using the preconcentration system was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 10 mg L(-1). After optimization, the method was successfully applied to the determination of Sc in an acid drainage from an abandoned mine located in the province of San Luis, Argentina. Copyright © 2014 Elsevier B.V. All rights reserved.

pH-based fiber optic biosensors for use in clinical and biotechnological applications

NASA Astrophysics Data System (ADS)

Mueller, Cord; Hitzmann, Bernd; Schubert, Florian; Scheper, Thomas

1995-05-01

The development of pH-based fiber optic biosensors and their uses in clinical and biotechnological applications are described. Based on a pH-sensitive optode, different biosensors for urea, penicillin, glucose and creatinine were developed. A multichannel modular fluorimeter was used to measure signals from up to three optodes simultaneously. The pH value and the buffer capacity are critical factors for biosensors based on pH probes and influence the biosensor signal. A flow injection analysis (FIA) system is used to eliminate the latter influences. With this integrated system, samples can be analyzed sequentially by the injection of a defined volume of each sample into a continuously flowing buffer stream that transports the samples to the sensors. The complex signal is transformed and analyzed by a computer system. Characteristic features of the FIA peak give information about the buffer capacity in the solution. With the help of intelligent computing (neural networks) it is possible to recognize these features and relate them to the respective buffer capacity to obtain more accurate values. Various applications of these biosensors are discussed. The pH optode is also used to monitor enzymatic reactions in non aqueous solvents. In this case the production of acetic acid can be detected on line.

Dissimilar viscosity induced sample pre-concentration in elecrokinetic nanofluidic channels

NASA Astrophysics Data System (ADS)

Wink, Dean; Shelton, Elijah; Pennathur, Sumita; Storey, Brian

2013-11-01

Nanofluidic analysis systems boast many advantages: portability, small sample handling, short processing times, and potential for integration with mobile electronics. However, such systems face the challenge of detecting increasingly small volumes of sample at low concentrations. In this work, we demonstrate a unique pre-concentration technique in electrokinetic nanofluidic systems based on a viscosity mismatch between two fluids. In nanofluidic electrokinetic systems, finite electric double layers (EDL) lead to non-uniform electric potentials and transverse concentration distributions. Therefore, when the EDL is comparable in size to the channel height, negatively charged ions are repelled from negatively charged walls and preferentially populate the channel centerline. Furthermore, an axial piecewise viscosity distribution induces internal pressure gradients within the channel. These force the ions to move at a different average velocities based on the pressure gradient being favorable or adverse, leading to focusing. To experimentally probe this phenomenon, we electrokinetically inject solutions of borate buffer with and without glycerol (to change the viscosity) and use a fluorescent tracer dye to visualize the flow. We perform the injections in cross-geometry channels of 20 micron, 1 micron, and 250 nanometer depths. We measure fluorescence at 5, 10 and 15 mm distances from junction. Enhancement is characterized by comparing intensities to control measurements for systems with uniform viscosity.

High-efficiency headspace sampling of volatile organic compounds in explosives using capillary microextraction of volatiles (CMV) coupled to gas chromatography-mass spectrometry (GC-MS).

PubMed

Fan, Wen; Almirall, José

2014-03-01

A novel geometry configuration based on sorbent-coated glass microfibers packed within a glass capillary is used to sample volatile organic compounds, dynamically, in the headspace of an open system or in a partially open system to achieve quantitative extraction of the available volatiles of explosives with negligible breakthrough. Air is sampled through the newly developed sorbent-packed 2 cm long, 2 mm diameter capillary microextraction of volatiles (CMV) and subsequently introduced into a commercially available thermal desorption probe fitted directly into a GC injection port. A sorbent coating surface area of ∼5 × 10(-2) m(2) or 5,000 times greater than that of a single solid-phase microextraction (SPME) fiber allows for fast (30 s), flow-through sampling of relatively large volumes using sampling flow rates of ∼1.5 L/min. A direct comparison of the new CMV extraction to a static (equilibrium) SPME extraction of the same headspace sample yields a 30 times improvement in sensitivity for the CMV when sampling nitroglycerine (NG), 2,4-dinitrotoluene (2,4-DNT), and diphenylamine (DPA) in a mixture containing a total mass of 500 ng of each analyte, when spiked into a liter-volume container. Calibration curves were established for all compounds studied, and the recovery was determined to be ∼1 % or better after only 1 min of sampling time. Quantitative analysis is also possible using this extraction technique when the sampling temperature, flow rate, and time are kept constant between calibration curves and the sample.

Droplet-based magnetically activated cell separation: analysis of separation efficiency based on the variation of flow-induced circulation in a pendent drop.

PubMed

Kim, Youngho; Lee, Sang Ho; Kim, Byungkyu

2009-12-01

Under the assumption that separation efficiencies are mainly affected by the velocity of flow-induced circulation due to buffer injection in a pendent drop, this paper describes an analysis of the separation efficiency of a droplet-based magnetically activated cell separation (DMACS) system. To investigate the velocity of the flow-induced circulation, we supposed that numerous flows in a pendent drop could be considered as a "theoretically normalized" flow (or conceptually normalized flow, CNF) based on the Cauchy-Goursat theorem. With the morphological characteristics (length and duration time) of a pendent drop depending on the initial volume, we obtained the velocities of the CNF. By measuring the separation efficiencies for different initial volumes and by analyzing the separation efficiency in terms of the velocity of the CNF, we found that the separation efficiencies (in the case of a low rate of buffer injection; 5 and 15 microl x min(-1)) are mainly affected by the velocity of the CNF. Moreover, we confirmed that the phenomenological features of a pendent drop cause a fluctuation of its separation efficiencies over a range of specific volumes (initial volumes ranging from 40 to 80 microl), because of the "sweeping-off" phenomenon, that is, positive cells gathered into the positive fraction are forced to move away from the magnetic side by flow-induced circulation due to buffer injection. In addition, from the variation of the duration time, that is, the interval between the beginning of injection of the buffer solution and the time at which a pendent drop detaches, it could also be confirmed that a shorter duration time leads to decrease of the number of positive cells in negative fraction regardless of the rate of buffer injection (5, 15, and 50 microl x min(-1)). Therefore, if a DMACS system is operated with a 15 microl x min(-1) buffer injection flow rate and an initial volume of 80 microl or more, we would have the best efficiency of separation in the negative fraction.

An in-situ stimulation experiment in crystalline rock - assessment of induced seismicity levels during stimulation and related hazard for nearby infrastructure

NASA Astrophysics Data System (ADS)

Gischig, Valentin; Broccardo, Marco; Amann, Florian; Jalali, Mohammadreza; Esposito, Simona; Krietsch, Hannes; Doetsch, Joseph; Madonna, Claudio; Wiemer, Stefan; Loew, Simon; Giardini, Domenico

2016-04-01

A decameter in-situ stimulation experiment is currently being performed at the Grimsel Test Site in Switzerland by the Swiss Competence Center for Energy Research - Supply of Electricity (SCCER-SoE). The underground research laboratory lies in crystalline rock at a depth of 480 m, and exhibits well-documented geology that is presenting some analogies with the crystalline basement targeted for the exploitation of deep geothermal energy resources in Switzerland. The goal is to perform a series of stimulation experiments spanning from hydraulic fracturing to controlled fault-slip experiments in an experimental volume approximately 30 m in diameter. The experiments will contribute to a better understanding of hydro-mechanical phenomena and induced seismicity associated with high-pressure fluid injections. Comprehensive monitoring during stimulation will include observation of injection rate and pressure, pressure propagation in the reservoir, permeability enhancement, 3D dislocation along the faults, rock mass deformation near the fault zone, as well as micro-seismicity. The experimental volume is surrounded by other in-situ experiments (at 50 to 500 m distance) and by infrastructure of the local hydropower company (at ~100 m to several kilometres distance). Although it is generally agreed among stakeholders related to the experiments that levels of induced seismicity may be low given the small total injection volumes of less than 1 m3, detailed analysis of the potential impact of the stimulation on other experiments and surrounding infrastructure is essential to ensure operational safety. In this contribution, we present a procedure how induced seismic hazard can be estimated for an experimental situation that is untypical for injection-induced seismicity in terms of injection volumes, injection depths and proximity to affected objects. Both, deterministic and probabilistic methods are employed to estimate that maximum possible and the maximum expected induced earthquake magnitude. Deterministic methods are based on McGarr's upper limit for the maximum induced seismic moment. Probabilistic methods rely on estimates of Shapiro's seismogenic index and seismicity rates from past stimulation experiments that are scaled to injection volumes of interest. Using rate-and-state frictional modelling coupled to a hydro-mechanical fracture flow model, we demonstrate that large uncontrolled rupture events are unlikely to occur and that deterministic upper limits may be sufficiently conservative. The proposed workflow can be applied to similar injection experiments, for which hazard to nearby infrastructure may limit experimental design.

The influence of injection volume and capsular bag contraction on the refractive power of polymer refilled lenses - a finite element modelling simulation study.

PubMed

Martin, Heiner; Guthoff, Rudolf; Schmitz, Klaus-Peter

2011-09-01

Polymer injection into the capsular bag after phakoemulsification is an interesting and promising approach to lens surgery. Safe clinical application of this technique will require an appropriate estimate of the effect of implantation variables on the lens power. This article details the results of finite element investigations into the effects of the injected polymer volume and capsular bag contraction on the resultant lens power and accommodation amplitude. An axisymmetric finite element model was created from literature sources. Polymer injection and the capsular contraction were simulated, and their effect on the lens power was calculated. The simulations show that overfilling during polymer injection leads to a refractive power increase of the lens. Capsular bag contraction also results in a power increase. The calculated accommodative amplitude of the lens is minimally affected by capsular bag contraction but decreases significantly with increased capsular bag stiffness as a result of fibrosis. © 2010 The Authors. Journal compilation © 2010 Acta Ophthalmol.

Plasma density injection and flow during coaxial helicity injection in a tokamak

NASA Astrophysics Data System (ADS)

Hooper, E. B.

2018-02-01

Whole device, resistive MHD simulations of spheromaks and tokamaks have used a large diffusion coefficient that maintains a nearly constant density throughout the device. In the present work, helicity and plasma are coinjected into a low-density plasma in a tokamak with a small diffusion coefficient. As in previous simulations [Hooper et al., Phys. Plasmas 20, 092510 (2013)], a flux bubble is formed, which expands to fill the tokamak volume. The injected plasma is non-uniform inside the bubble. The flow pattern is analyzed; when the simulation is not axisymmetric, an n = 1 mode on the surface of the bubble generates leakage of plasma into the low-density volume. Closed flux is generated following injection, as in experiments and previous simulations. The result provides a more detailed physics analysis of the injection, including density non-uniformities in the plasma that may affect its use as a startup plasma [Raman et al., Phys. Rev. Lett. 97, 175002 (2006)].

Effect of Low-Intensity Pulsed Ultrasound after Mesenchymal Stromal Cell Injection to Treat Osteochondral Defects: An In Vivo Study.

PubMed

Yamaguchi, Shoki; Aoyama, Tomoki; Ito, Akira; Nagai, Momoko; Iijima, Hirotaka; Tajino, Junichi; Zhang, Xiangkai; Wataru, Kiyan; Kuroki, Hiroshi

2016-12-01

We investigated the effect of low-intensity pulsed ultrasound (LIPUS) treatment combined with mesenchymal stromal cell (MSC) injection for cartilage repair and subchondral bone reconstitution for treatment of osteochondral defects. An osteochondral defect was created on both femur grooves of Wistar rats. Four weeks later, bone marrow MSCs were injected into the right knee joint. The rats were divided into two intervention groups: without or with LIPUS irradiation. Cartilage repair was evaluated histologically based on the Wakitani cartilage repair score. Subchondral bone reconstitution was evaluated as bone volume (BV)/tissue volume (TV) by micro-computed tomography analysis. MSC injection improved the cartilage repair score, and LIPUS irradiation improved BV/TV. Combination treatment promoted both cartilage repair and BV/TV improvement. Thus, MSC injection combined with LIPUS irradiation is more effective than either treatment alone in promoting concurrent cartilage repair and subchondral reconstitution. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Efficacy and durability of hyaluronic acid fillers for malar enhancement: A prospective, randomized, split-face clinical controlled trial.

PubMed

Jeong, Ki Heon; Gwak, Min Jae; Moon, Sung Kyung; Lee, Sang Jun; Shin, Min Kyung

2018-06-01

Various hyaluronic acid fillers can be used for facial attenuation and rejuvenation. The efficacy and durability of hyaluronic acid fillers are of major concern to dermatologists and patients. This study aimed to evaluate three-dimensional morphology, tissue distribution, and changes in volume after injection of two different hyaluronic acid fillers. Ten Korean women were enrolled in this study. Each subject was injected with monophasic hyaluronic acid filler in one malar area and biphasic filler in the other. Clinical outcome was measured before and after injection, and after 2, 4, 6, 8, 12, and 24 weeks, using the Global Aesthetic Improvement Scale, photographs and Moire's topography. Facial magnetic resonance imaging (MRI) was performed twice over six months. Both products showed good results after injection and demonstrated good durability over time. MRI was a useful modality for assessing tissue distribution and volume changes. The effects and durability after injection of monophasic hyaluronic acid filler and biphasic hyaluronic acid filler are generally comparable.

Selenium analysis by an integrated microwave digestion-needle trap device with hydride sorption on carbon nanotubes and electrothermal atomic absorption spectrometry determination

NASA Astrophysics Data System (ADS)

Maratta Martínez, Ariel; Vázquez, Sandra; Lara, Rodolfo; Martínez, Luis Dante; Pacheco, Pablo

2018-02-01

An integrated microwave assisted digestion (MW-AD) - needle trap device (NTD) for selenium determination in grape pomace samples is presented. The NTD was filled with oxidized multiwall carbon nanotubes (oxMWCNTS) where Se hydrides were preconcentrated. Determination was carried out by flow injection-electrothermal atomic absorption spectrometry (FI-ETAAS). The variables affecting the system were established by a multivariate design (Plackett Burman), indicating that the following variables significantly affect the system: sample amount, HNO3 digestion solution concentration, NaBH4 volume and elution volume. A Box-Behnken design was implemented to determine the optimized values of these variables. The system improved Se atomization in the graphite furnace, since only trapped hydrides reached the graphite furnace, and the pyrolysis stage was eliminated according to the aqueous matrix of the eluate. Under optimized conditions the system reached a limit of quantification of 0.11 μg kg- 1, a detection limit of 0.032 μg kg- 1, a relative standard deviation of 4% and a preconcentration factor (PF) of 100, reaching a throughput sample of 5 samples per hour. Sample analysis show Se concentrations between 0.34 ± 0.03 μg kg- 1 to 0.48 ± 0.03 μg kg- 1 in grape pomace. This system provides minimal reagents and sample consumption, eliminates discontinuous stages between samples processing reaching a simpler and faster Se analysis.

Sample preconcentration with chemical derivatization in capillary electrophoresis. Capillary as preconcentrator, microreactor and chiral selector for high-throughput metabolite screening.

PubMed

Ptolemy, Adam S; Britz-McKibbin, Philip

2006-02-17

New strategies for integrating sample pretreatment with chemical analyses under a single format is required for rapid, sensitive and enantioselective analyses of low abundance metabolites in complex biological samples. Capillary electrophoresis (CE) offers a unique environment for controlling analyte/reagent band dispersion and electromigration properties using discontinuous electrolyte systems. Recent work in our laboratory towards developing a high-throughput CE platform for low abundance metabolites via on-line sample preconcentration with chemical derivatization (SPCD) is primarily examined in this review, as there have been surprisingly only a few strategies reported in the literature to date. In-capillary sample preconcentration serves to enhance concentration sensitivity via electrokinetic focusing of long sample injection volumes for lower detection limits, whereas chemical derivatization by zone passing is used to expand detectability and selectivity, notably for enantiomeric resolution of metabolites lacking intrinsic chromophores using nanolitre volumes of reagent. Together, on-line SPCD-CE can provide over a 100-fold improvement in concentration sensitivity, shorter total analysis times, reduced sample handling and improved reliability for a variety of amino acid and amino sugar metabolites, which is also amenable to automated high-throughput screening. This review will highlight basic method development and optimization parameters relevant to SPCD-CE, including applications to bacterial metabolite flux and biomarker analyses. Insight into the mechanism of analyte focusing and labeling by SPCD-CE is also discussed, as well as future directions for continued research.

Aquifer Thermal Energy Storage : A Well Doublet Experiment at Increased Temperatures

NASA Astrophysics Data System (ADS)

Molz, F. J.; Melville, J. G.; Parr, A. D.; King, D. A.; Hopf, M. T.

1983-02-01

The two main objectives of this communication are to present a study of potential advantages and disadvantages of the doublet supply-injection well configuration in an aquifer thermal energy storage (ATES) system and to report on aquifer storage problems with injection temperatures in the 80°C range. A 3-month injection-storage-recovery cycle followed by a 7.3-month cycle constituted the main experiment. The injection volumes were 25,402 m3 and 58,063 m3 at average temperatures of 58.5°C and 81°C respectively. Unlikely previous experiments at the Mobile site, no clogging of the injection well due to clay particle swelling, dispersion, and migration was observed. This is attributed to the fact that the supply water used for injection contained a cation concentration equal to or slightly greater than that in the native groundwater. For cycles I and II, the fraction of injected energy recovered in a volume of water equal to the injection volume was 0.56 and 0.45 respectively. Both groundwater temperature and tracer data support the conclusion that this relatively low recovery was due to the detrimental effects of free thermal convection, possibly augmented by longitudinal zones of high permeability. Construction of a partially penetrating recovery well improved recovery efficiency but is not thought to be an adequate solution to thermal stratification. A maximum increase of 1.24 cm in relative land surface elevation was recorded near the end of second cycle injection. The engineering implications of such an elevation change would have to be considered, especially if an ATES system were being designed in an urban environment. A third cycle was started at the Mobile site on April 7, 1982. This final experiment contains a partially penetrating, dual-recovery well system which is expected to maximize energy recovery from a thermally stratified storage aquifer.

Micro-Computed Tomography Evaluation of Human Fat Grafts in Nude Mice

PubMed Central

Chung, Michael T.; Hyun, Jeong S.; Lo, David D.; Montoro, Daniel T.; Hasegawa, Masakazu; Levi, Benjamin; Januszyk, Michael; Longaker, Michael T.

2013-01-01

Background Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported survival rates of fat grafts to vary anywhere between 10% and 80% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis. Methods Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of 10 adult Crl:NU-Foxn1nu CD-1 male mice. Micro-computed tomography (CT) was performed immediately following injection and then weekly thereafter. Fat volume was rendered by reconstructing a three-dimensional (3D) surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E), for macrophages using CD68 and for the cannabinoid receptor 1 (CB1). Finally, samples were explanted at 8- and 12-week time points to validate calculated micro-CT volumes. Results Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8- and 12-week time points stabilized, showing an average of 62.2% and 60.9% survival, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis and staining for CD68 showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed human origin of the adipocytes. Conclusions Studies assessing the fate of autologous fat grafts in animals have focused on nonimaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly, this model provides a platform for subsequent study of fat manipulation and soft tissue engineering. PMID:22916732

Effects of Pre and Post-Rigor Marinade Injection on Some Quality Parameters of Longissimus Dorsi Muscles

PubMed Central

Fadıloğlu, Eylem Ezgi; Serdaroğlu, Meltem

2018-01-01

Abstract This study was conducted to evaluate the effects of pre and post-rigor marinade injections on some quality parameters of Longissimus dorsi (LD) muscles. Three marinade formulations were prepared with 2% NaCl, 2% NaCl+0.5 M lactic acid and 2% NaCl+0.5 M sodium lactate. In this study marinade uptake, pH, free water, cooking loss, drip loss and color properties were analyzed. Injection time had significant effect on marinade uptake levels of samples. Regardless of marinate formulation, marinade uptake of pre-rigor samples injected with marinade solutions were higher than post rigor samples. Injection of sodium lactate increased pH values of samples whereas lactic acid injection decreased pH. Marinade treatment and storage period had significant effect on cooking loss. At each evaluation period interaction between marinade treatment and injection time showed different effect on free water content. Storage period and marinade application had significant effect on drip loss values. Drip loss in all samples increased during the storage. During all storage days, lowest CIE L* value was found in pre-rigor samples injected with sodium lactate. Lactic acid injection caused color fade in pre-rigor and post-rigor samples. Interaction between marinade treatment and storage period was found statistically significant (p<0.05). At day 0 and 3, the lowest CIE b* values obtained pre-rigor samples injected with sodium lactate and there were no differences were found in other samples. At day 6, no significant differences were found in CIE b* values of all samples. PMID:29805282

Effects of Pre and Post-Rigor Marinade Injection on Some Quality Parameters of Longissimus Dorsi Muscles.

PubMed

Fadıloğlu, Eylem Ezgi; Serdaroğlu, Meltem

2018-04-01

This study was conducted to evaluate the effects of pre and post-rigor marinade injections on some quality parameters of Longissimus dorsi (LD) muscles. Three marinade formulations were prepared with 2% NaCl, 2% NaCl+0.5 M lactic acid and 2% NaCl+0.5 M sodium lactate. In this study marinade uptake, pH, free water, cooking loss, drip loss and color properties were analyzed. Injection time had significant effect on marinade uptake levels of samples. Regardless of marinate formulation, marinade uptake of pre-rigor samples injected with marinade solutions were higher than post rigor samples. Injection of sodium lactate increased pH values of samples whereas lactic acid injection decreased pH. Marinade treatment and storage period had significant effect on cooking loss. At each evaluation period interaction between marinade treatment and injection time showed different effect on free water content. Storage period and marinade application had significant effect on drip loss values. Drip loss in all samples increased during the storage. During all storage days, lowest CIE L* value was found in pre-rigor samples injected with sodium lactate. Lactic acid injection caused color fade in pre-rigor and post-rigor samples. Interaction between marinade treatment and storage period was found statistically significant ( p <0.05). At day 0 and 3, the lowest CIE b* values obtained pre-rigor samples injected with sodium lactate and there were no differences were found in other samples. At day 6, no significant differences were found in CIE b* values of all samples.

The active and passive sampling of benzene, toluene, ethyl benzene and xylenes compounds using the inside needle capillary adsorption trap device.

PubMed

Shojania, S; Oleschuk, R D; McComb, M E; Gesser, H D; Chow, A

1999-08-23

A new and simple method of solventless extraction of volatile organic compounds (VOCs) from air is presented. The sampling device has an adsorbing carbon coating on the interior surface of a hollow needle, and is called the inside needle capillary adsorption trap (INCAT). This paper describes a study of the reproducibility in the preparation and sampling of the INCAT device. In addition, this paper examines the effects of sample volume in active sampling and exposure time in passive sampling on the analyte adsorption. Analysis was achieved by sampling the air from an environmental chamber doped with benzene, toluene, ethyl benzene and xylenes (BTEX) compounds. Initial rates of adsorption were found to vary among the different compounds, but ranged from 0.0099 to 0.016 nmol h(-1) for passive sampling and from 2.2 to 10 nmol h(-1) for active sampling. Analysis was done by thermal desorption of the adsorbed compounds directly into a gas chromatograph injection port. Quantification of the analysis was done by comparison to actively sampled activated carbon solid phase extraction (SPE) measurements.

A potential relationship between skin hydration and stamp-type microneedle intradermal hyaluronic acid injection in middle-aged male face.

PubMed

Seok, Joon; Hong, Ji Yeon; Choi, Sun Young; Park, Kui Young; Kim, Beom Joon

2016-12-01

There is an increasing interest in skin rejuvenation using hyaluronic acid (HA) fillers beyond the improvement of deep wrinkles and volume deficiencies, which have been primary research foci in the past. We conducted a pilot study using a sample of six middle-aged male subjects. Using an automatic intradermal injector with 0.020 mL of material contained in each injection point with a total of 100 points, 2 mL of non-cross-HA filler was injected into the entire face at every treatment session. We administered injections of HA for a total of three sessions per subject at 2-week intervals and evaluated the results using a corneometer, TEWL, cutometer, measures of patient satisfaction, and the global aesthetic improvement scale (GAIS). Corneometer values increased steadily at each measurement, while the average value of TEWL increased in comparison with baseline after each application of the procedure. However, values returned to readings similar to those at 4 weeks after complete termination of the procedures. Cutometer values differed between the baseline and after procedures. All patients were assessed as "very much improved" or "much improved" according to GAIS, and all were pleased with the outcomes of treatment in terms of the enhancement of moisture, elasticity, and brightness. © 2016 Wiley Periodicals, Inc.

Estimation of the quantification uncertainty from flow injection and liquid chromatography transient signals in inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Laborda, Francisco; Medrano, Jesús; Castillo, Juan R.

2004-06-01

The quality of the quantitative results obtained from transient signals in high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) was investigated under multielement conditions. Quantification methods were based on multiple-point calibration by simple and weighted linear regression, and double-point calibration (measurement of the baseline and one standard). An uncertainty model, which includes the main sources of uncertainty from FI-ICPMS and HPLC-ICPMS (signal measurement, sample flow rate and injection volume), was developed to estimate peak area uncertainties and statistical weights used in weighted linear regression. The behaviour of the ICPMS instrument was characterized in order to be considered in the model, concluding that the instrument works as a concentration detector when it is used to monitorize transient signals from flow injection or chromatographic separations. Proper quantification by the three calibration methods was achieved when compared to reference materials, although the double-point calibration allowed to obtain results of the same quality as the multiple-point calibration, shortening the calibration time. Relative expanded uncertainties ranged from 10-20% for concentrations around the LOQ to 5% for concentrations higher than 100 times the LOQ.

Ultra preconcentration of polycyclic aromatic hydrocarbons in smoked bacon by a combination of SPE and DLLME.

PubMed

Liu, Xiaofang; Zhou, Shu; Zhu, Quanfei; Ye, Yong; Chen, Huaixia

2014-09-01

A sample pretreatment method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was established for the sensitive determination of polycyclic aromatic hydrocarbons (PAHs) in smoked bacon samples. In the SPE-DLLME process, three PAHs including naphthalene (Naph), phenanthrene (Phen) and pyrene (Pyr) were extracted from samples and transferred into C18 SPE cartridge. The target analytes were subsequently eluted with 1.2 ml of acetonitrile-dichloromethane (5:1, v/v) mixture solution. The eluent was injected directly into the 5.0 ml ultrapure water in the subsequent DLLME procedure. The sedimented phase was concentrated under a gentle nitrogen flow to 120.0 µl. Finally, the analytes in the extraction solvent were determined by high-performance liquid chromatography with a ultra-violet detector. Some important extraction parameters affecting the performance, such as the sample solution flow rate, breakthrough volume, salt addition as well as the type and volume of the elution solvent were optimized. The developed method provided an ultra enrichment factors for PAHs ranged from 3478 to 3824. The method was applied for the selective extraction and sensitive determination of PAHs in smoked bacon samples. The limits of detection (S/N = 3) were 0.05, 0.01, 0.02 μg kg(-1) for Naph, Phen, Pyr, respectively. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Potential environmental issues of CO2 storage in deep saline aquifers: Geochemical results from the Frio-I Brine Pilot test, Texas, USA

USGS Publications Warehouse

Kharaka, Yousif K.; Thordsen, James J.; Hovorka, Susan D.; Nance, H. Seay; Cole, David R.; Phelps, Tommy J.; Knauss, Kevin G.

2009-01-01

Sedimentary basins in general, and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO2 that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO2 in such aquifers, 1600 t of CO2 were injected at 1500 m depth into a 24-m-thick "C" sandstone unit of the Frio Formation, a regional aquifer in the US Gulf Coast. Fluid samples obtained before CO2 injection from the injection well and an observation well 30 m updip showed a Na–Ca–Cl type brine with ∼93,000 mg/L TDS at saturation with CH4 at reservoir conditions; gas analyses showed that CH4 comprised ∼95% of dissolved gas, but CO2 was low at 0.3%. Following CO2 breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5–5.7), pronounced increases in alkalinity (100–3000 mg/L as HCO3) and in Fe (30–1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H2O, DIC, and CH4. These data, coupled with geochemical modeling, indicate corrosion of pipe and well casing as well as rapid dissolution of minerals, especially calcite and iron oxyhydroxides, both caused by lowered pH (initially ∼3.0 at subsurface conditions) of the brine in contact with supercritical CO2.These geochemical parameters, together with perfluorocarbon tracer gases (PFTs), were used to monitor migration of the injected CO2 into the overlying Frio “B”, composed of a 4-m-thick sandstone and separated from the “C” by ∼15 m of shale and siltstone beds. Results obtained from the Frio “B” 6 months after injection gave chemical and isotopic markers that show significant CO2 (2.9% compared with 0.3% CO2 in dissolved gas) migration into the “B” sandstone. Results of samples collected 15 months after injection, however, are ambiguous, and can be interpreted to show no additional injected CO2 in the “B” sandstone. The presence of injected CO2 may indicate migration from “C” to “B” through the intervening beds or, more likely, a short-term leakage through the remedial cement around the casing of a 50-year old well. Results obtained to date from four shallow monitoring groundwater wells show no brine or CO2 leakage through the Anahuac Formation, the regional cap rock.

Computed tomography analysis of third webspace injections for interdigital neuroma.

PubMed

Hembree, W Chad; Groth, Adam T; Schon, Lew C; Guyton, Gregory P

2013-04-01

Injection for interdigital neuroma (IDN) may not selectively target the common digital nerve. We investigated the anatomical localization and extent of extravasation with injection for IDN. Two fellowship-trained foot and ankle surgeons injected radiopaque contrast into the third webspace of 49 cadaveric specimens (29 with 2 mL and 20 with 1 mL). Computed tomography scan of each specimen was obtained. An independent blinded foot and ankle surgeon analyzed the scans. All injections were accurate. Contrast was found in the second (greater than 70%) and fourth (greater than 30%) webspaces in both injection volume groups. No contrast was found within the third metatarsophalangeal joint. Extravasation extent was significantly greater with 2 mL versus 1 mL of solution in the medial to lateral (27.9 [7.8] mm vs 23.7 [6.0] mm; P = .05) and distal to proximal (52.1 [13.7] mm vs 40.4 [16.1] mm; P = .01) planes. No differences were observed in extravasation extent between surgeons. Injection for IDN was accurate, and extravasation extended into adjacent webspaces in a large percentage of specimens with both solution volumes. Lower extent of extravasation with 1 mL of solution did not indicate better selectivity of injection. Steroid injections for interdigital neuroma were accurate for therapeutic purposes but not diagnostic, except potentially for distinguishing webspace pain from joint pain.

Microscale depletion of high abundance proteins in human biofluids using IgY14 immunoaffinity resin: analysis of human plasma and cerebrospinal fluid.

PubMed

Hyung, Seok-Won; Piehowski, Paul D; Moore, Ronald J; Orton, Daniel J; Schepmoes, Athena A; Clauss, Therese R; Chu, Rosalie K; Fillmore, Thomas L; Brewer, Heather; Liu, Tao; Zhao, Rui; Smith, Richard D

2014-11-01

Removal of highly abundant proteins in plasma is often carried out using immunoaffinity depletion to extend the dynamic range of measurements to lower abundance species. While commercial depletion columns are available for this purpose, they generally are not applicable to limited sample quantities (<20 μL) due to low yields stemming from losses caused by nonspecific binding to the column matrix and concentration of large eluent volumes. Additionally, the cost of the depletion media can be prohibitive for larger-scale studies. Modern LC-MS instrumentation provides the sensitivity necessary to scale-down depletion methods with minimal sacrifice to proteome coverage, which makes smaller volume depletion columns desirable for maximizing sample recovery when samples are limited, as well as for reducing the expense of large-scale studies. We characterized the performance of a 346 μL column volume microscale depletion system, using four different flow rates to determine the most effective depletion conditions for ∼6-μL injections of human plasma proteins and then evaluated depletion reproducibility at the optimum flow rate condition. Depletion of plasma using a commercial 10-mL depletion column served as the control. Results showed depletion efficiency of the microscale column increased as flow rate decreased, and that our microdepletion was reproducible. In an initial application, a 600-μL sample of human cerebrospinal fluid (CSF) pooled from multiple sclerosis patients was depleted and then analyzed using reversed phase liquid chromatography-mass spectrometry to demonstrate the utility of the system for this important biofluid where sample quantities are more commonly limited.

Combining CO2 sequestration and CH4 production by means of guest exchange in a gas hydrate reservoir: two pilot scale experiments

NASA Astrophysics Data System (ADS)

Heeschen, Katja U.; Spangenberg, Erik; Schicks, Judith M.; Deusner, Christian; Priegnitz, Mike; Strauch, Bettina; Bigalke, Nikolaus; Luzi-Helbing, Manja; Kossel, Elke; Haeckel, Matthias; Wang, Yi

2017-04-01

Methane (CH4) hydrates are considered as a player in the field of energy supply and - if applied as such - as a possible sink for the greenhouse gas carbon dioxide (CO2). Next to the more conventional production methods depressurization and thermal stimulation, an extraction of CH4 by means of CO2 injection is investigated. The method is based on the chemical potential gradient between the CH4 hydrate phase and the injected CO2 phase. Results from small-scale laboratory experiments on the replacement method indicate recovery ratios of up to 66% CH4 but also encounter major discrepancies in conversion rates. So far it has not been demonstrated with certainty that the process rates are sufficient for an energy and cost effective production of CH4 with a concurrent sequestration of CO2. In a co-operation of GFZ and GEOMAR we used LARS (Large Scale Reservoir Simulator) to investigate the CO2-CH4-replacement method combined with thermal stimulation. LARS accommodates a sample volume of 210 l and allows for the simulation of in situ conditions typically found in gas hydrate reservoirs. Based on the sample size, diverse transport mechanisms could be simulated, which are assumed to significantly alter process yields. Temperature and pressure data complemented by a high resolution electrical resistivity tomography (ERT), gas chromatography, and flow measurements serve to interpret the experiments. In two experiments 50 kg heated CO2 was injected into sediments with CH4 hydrate saturations of 50%. While in the first experiment the CO2 was injected discontinuously in a so called "huff'n puff" manner, the second experiment saw a continuous injection. Conditions within LARS were set to 13 MPa and 8˚ C, which allow for stability of pure CO2 and CH4 hydrates as well as mixed hydrates. The CO2 was heated and entered the sediment sample with temperatures of approximately 30˚ C. In this presentation we will discuss the results from the large-scale experiments and compare them with data from small-scale experiments.

Image-guided intraocular injection using multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy in rodent ophthalmological models

NASA Astrophysics Data System (ADS)

Terrones, Benjamin D.; Benavides, Oscar R.; Leeburg, Kelsey C.; Mehanathan, Sankarathi B.; Levine, Edward M.; Tao, Yuankai K.

2018-02-01

Intraocular injections are routinely performed for delivery of anti-VEGF and anti-inflammatory therapies in humans. While these injections are also performed in mice to develop novel models of ophthalmic diseases and screen novel therapeutics, the injection location and volume are not well-controlled and reproducible. We overcome limitations of conventional injections methods by developing a multimodality, long working distance, non-contact optical coherence tomography (OCT) and fluorescence confocal scanning laser ophthalmoscopy (cSLO) system for retinal imaging before and after injections. Our OCT+cSLO system combines a custom-built spectraldomain OCT engine (875+/-85 nm) with 125 kHz line-rate with a modified commercial cSLO with a maximum frame-rate of 30 fps (512 x 512 pix.). The system was designed for an overlapping OCT+cSLO field-of-view of 1.1 mm with a 7.76 mm working distance to the pupil. cSLO excitation light sources and filters were optimized for simultaneous GFP and tdTomato imaging. Lateral resolution was 3.02 µm for OCT and 2.74 μm for cSLO. Intravitreal injections of 5%, 10%, and 20% intralipid with Alex Fluor 488 were manually injected intraocularly in C57BL/6 mice. Post-injection imaging showed structural changes associated with retinal puncture, including the injection track, a retinal elevation, and detachment of the posterior hyaloid. OCT enables quantitative analysis of injection location and volumes whereas complementary cSLO improves specificity for identifying fluorescently labeled injected compounds and transgenic cells. The long working distance of our non-contact OCT+cSLO system is uniquely-suited for concurrent imaging with intraocular injections and may be applied for imaging of ophthalmic surgical dynamics and real-time image-guided injections.

The Efficacy of Cyclic Injection of Bone Morphogenetic Protein-2 in Large-Scale Calvarial Bone Defects.

PubMed

Choi, Jin Mi; Jeong, Woo Shik; Park, Eun Jung; Choi, Jong Woo

2017-03-01

Bone morphogenetic protein-2 (BMP-2) appears to be one of the most potent growth factors thus far studied. However, recent publications on the clinical application of BMP-2 revealed that its correct control is the paramount issue in clinical practice. For improving BMP-2 delivery, the cyclic administration might be an alternative. Accordingly, the authors cyclically injected BMP-2 in a cyclic injection model of large cranial defects to maintain the proper dosage during the bone healing process. A 10-mm diameter calvarial bone defect was produced using a round drill in 8-week-old Sprague-Dawley rats. Silk-hydroxyapatite scaffolds soaked in the appropriate concentration of BMP-2 were implanted into the defect. The animals were split into 4 single-injection groups and 3 multiple-injection groups; the latter groups received weekly subcutaneous injections of BMP-2 solution (1, 5, and 10 μg/mL) for 4 weeks, whereas the former groups received a single injection of BMP-2 at these concentrations. Each rat underwent computed tomography at 8 weeks. In terms of total volumes of the new bone, the 5 μg/mL multiple-injection BMP-2 group had significantly greater increases in bone volume than the single-injection groups. In terms of bone thickness, the multiple-injection groups had better outcomes than the single-injection groups. Thus, the cyclic injection protocol restored the original thickness without overgrowth. Cyclic injection of BMP-2 permits more accurate dosage control than single injection and improves thickness and dense bone regeneration. Therefore, it may represent a promising approach for future clinical trials. Further investigation using a greater number of animals is required.

Helium Nanobubbles Enhance Superelasticity and Retard Shear Localization in Small-Volume Shape Memory Alloy.

PubMed

Han, Wei-Zhong; Zhang, Jian; Ding, Ming-Shuai; Lv, Lan; Wang, Wen-Hong; Wu, Guang-Heng; Shan, Zhi-Wei; Li, Ju

2017-06-14

The intriguing phenomenon of metal superelasticity relies on stress-induced martensitic transformation (SIMT), which is well-known to be governed by developing cooperative strain accommodation at multiple length scales. It is therefore scientifically interesting to see what happens when this natural length scale hierarchy is disrupted. One method is producing pillars that confine the sample volume to micrometer length scale. Here we apply yet another intervention, helium nanobubbles injection, which produces porosity on the order of several nanometers. While the pillar confinement suppresses superelasticity, we found the dispersion of 5-10 nm helium nanobubbles do the opposite of promoting superelasticity in a Ni 53.5 Fe 19.5 Ga 27 shape memory alloy. The role of helium nanobubbles in modulating the competition between ordinary dislocation slip plasticity and SIMT is discussed.

Investigating the relationship between seismicity and fluid injection in the Barnett Shale, Texas using coupled poroelastic model and surface deformation data

NASA Astrophysics Data System (ADS)

Zhai, G.; Shirzaei, M.

2017-12-01

Across the Barnett Shale, Texas a noticeable increase in seismic activity was observed during 2007 and 2015, which was accompanied by high volume injection at several nearby disposal wells. Many studies focused on the positive correlation between injection rate at individual wells and the adjacent seismicity, suggesting that seismicity is triggered or induced due to increased pore fluid pressure associated with fluid injection in hydraulically connected geological units. However, investigating temporal evolution of total volume of injected fluid and concurrent earthquakes in a larger area indicates more complex patterns, requiring a more comprehensive analysis of the spatiotemporal evolution of coupled poroelastic stress and pore fluid pressure. In this study, we created a coupled poroelastic model to simulate large scale spatiotemporal evolution of pore pressure, poroelastic stresses, and Coulomb failure stress in the Barnett Shale using injection time series of 96 high-volume injection wells spanning from 2007 to 2015. We additionally account for a layered poroelastic medium, where its parameters are set up using geological maps and seismic tomographic data sets. Fault orientations and relevant frictional properties are also extracted from published literatures. We further integrate observation of surface deformation obtained from interferometric processing of 16 ALOS L-Band SAR images to optimize rock hydraulic diffusivity and constrain the extent to which fluid may migrate. The preliminary modeling result shows that poroelastic stress is only 10% of pore pressure. However, the superimposition of these two effects is spatially and temporally responsible for the occurrence of earthquakes in the Barnett Shale. Also, not all area with increased Coulomb failure stress experiences elevated seismicity, suggesting possible heterogeneous background tectonic stresses, lacking pre-existing faults, and/or heterogeneous fault orientations.

Quantitative Determination of Fluorinated Alkyl Substances by Large-Volume-Injection LC/MS/MS—Characterization of Municipal Wastewaters

PubMed Central

Schultz, Melissa M.; Barofsky, Douglas F.; Field, Jennifer A.

2008-01-01

A quantitative method was developed for the determination of fluorinated alkyl substances in municipal wastewater influents and effluents. The method consisted of centrifugation followed by large-volume injection (500 μL) of the supernatant onto a liquid chromatograph with a reverse-phase column and detection by electrospray ionization, and tandem mass spectrometry (LC/MS/MS). The fluorinated analytes studied include perfluoroalkyl sulfonates, fluorotelomer sulfonates, perfluorocarboxylates, and select fluorinated alkyl sulfonamides. Recoveries of the fluorinated analytes from wastewater treatment plant (WWTP) raw influents and final effluent ranged from 77% – 96% and 80% – 99%, respectively. The lower limit of quantitation ranged from 0.5 to 3.0 ng/L depending on the analyte. The method was applied to flow-proportional composites of raw influent and final effluent collected over a 24 hr period from ten WWTPs nationwide. Fluorinated alkyl substances were observed in wastewater at all treatment plants and each plant exhibited unique distributions of fluorinated alkyl substances despite similarities in treatment processes. In nine out of the ten plants sampled, at least one class of fluorinated alkyl substances exhibited increased concentrations in the effluent as compared to the influent concentrations. In some instances, decreases in certain fluorinated analyte concentrations were observed and attributed to sorption to sludge. PMID:16433363

Depletion of penicillin G residues in heavy sows after intramuscular injection. Part I: Tissue residue depletion

USDA-ARS?s Scientific Manuscript database

Heavy sows (n=126) were treated with penicillin G procaine at a 5x label dose (33,000 IU/kg) for 3 consecutive days by intramuscular (IM) injection using 3 separate patterns (treatments) of drug administration (42 sows per treatment). Treatments differed by pattern and maximum injection volume per s...

Detection and three-dimensional visualization of lesion models using sonoelastography

NASA Astrophysics Data System (ADS)

Taylor, Lawrence S.; Gaborski, Thomas R.; Strang, John G.; Rubens, Deborah; Parker, Kevin J.

2002-04-01

Sonoelastography is a vibration Doppler technique for imaging the relative elasticity of tissues. Detectability of hard lesions of various sizes has previously been demonstrated in tissue phantoms by our group. Because real tissue differs from phantom material, the injection of formaldehyde in fresh liver tissue is being used as an in-vitro lesion model. Pieces of fresh calf liver were embedded in an agar gel then injected with a bolus of 37% formaldehyde to create a stiff lesion. Two and three-dimensional sonoelastography and b-mode images were acquired. The lesions were visible in each sonoelastography image as a region of reduced vibration. After imaging, lesions were dissected and measured for size and volume. One 0.4 cc bolus injection of formaldehyde created a lesion with a volume of 10.3 cc in the sonoelastography image compared to 9.3 cc using fluid displacement of the dissected lesion. A 0.33 cc injection of formaldehyde lesion created a volume of 5 cc in the sonoelastography image compared to 4.4 cc using fluid displacement. Sonoelastography imaging techniques for imaging hard lesions in phantoms can be successfully extended to imaging formaldehyde induced lesions in real tissue.

Does the combination of 3% mepivacaine plain plus 2% lidocaine with epinephrine improve anesthesia and reduce the pain of anesthetic injection for the inferior alveolar nerve block? A prospective, randomized, double-blind study.

PubMed

Lammers, Emily; Nusstein, John; Reader, Al; Drum, Melissa; Beck, Mike; Fowler, Sara

2014-09-01

In theory, using 3% mepivacaine initially for an inferior alveolar nerve (IAN) block would decrease the pain of injection, provide faster onset, and increase anesthetic success. The purpose of this prospective, randomized, double-blind study was to compare the degree of pulpal anesthesia obtained with a combination of 3% mepivacaine/2% lidocaine (1:100,000 epinephrine) versus a combination of 2% lidocaine (1:100,000 epinephrine)/2% lidocaine (1:100,000 epinephrine) in IAN blocks. Injection pain was also studied. One hundred asymptomatic subjects were randomly given a combination of a 1-cartridge volume of 3% mepivacaine plus a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine and a combination of a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine plus a 1-cartridge volume of 2% lidocaine with 1:100,000 epinephrine for the IAN block at 2 separate appointments. Subjects rated the pain of injection. The molars, premolars, and incisors were tested with an electric pulp tester in 4-minute cycles for 60 minutes. Anesthetic success was defined as the subject achieving 2 consecutive 80 readings within 15 minutes after completion of the IAN blocks and sustaining the 80 reading for 60 minutes. Success was not significantly different (P > .05) between the 2 combinations. No statistical differences in injection pain or onset times were found. The combination of 3% mepivacaine plus 2% lidocaine with 1:100,000 epinephrine was equivalent to the combination of 2 cartridges of 2% lidocaine with 1:100,000 epinephrine in terms of injection pain, onset time, and pulpal anesthetic success for the IAN block. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Design of an interface to allow microfluidic electrophoresis chips to drink from the fire hose of the external environment.

PubMed

Attiya, S; Jemere, A B; Tang, T; Fitzpatrick, G; Seiler, K; Chiem, N; Harrison, D J

2001-01-01

An interface design is presented that facilitates automated sample introduction into an electrokinetic microchip, without perturbing the liquids within the microfluidic device. The design utilizes an interface flow channel with a volume flow resistance that is 0.54-4.1 x 10(6) times lower than the volume flow resistance of the electrokinetic fluid manifold used for mixing, reaction, separation, and analysis. A channel, 300 microm deep, 1 mm wide and 15-20 mm long, was etched in glass substrates to create the sample introduction channel (SIC) for a manifold of electrokinetic flow channels in the range of 10-13 microm depth and 36-275 microm width. Volume flow rates of up to 1 mL/min were pumped through the SIC without perturbing the solutions within the electrokinetic channel manifold. Calculations support this observation, suggesting a leakage flow to electroosmotic flow ratio of 0.1:1% in the electrokinetic channels, arising from 66-700 microL/min pressure-driven flow rates in the SIC. Peak heights for capillary electrophoresis separations in the electrokinetic flow manifold showed no dependence on whether the SIC pump was on or off. On-chip mixing, reaction and separation of anti-ovalbumin and ovalbumin could be performed with good quantitative results, independent of the SIC pump operation. Reproducibility of injection performance, estimated from peak height variations, ranged from 1.5-4%, depending upon the device design and the sample composition.

Direct analysis of δ13C and concentration of dissolved organic carbon (DOC) in environmental samples by TOC-IRMS

NASA Astrophysics Data System (ADS)

Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Kalbitz, Karsten

2014-05-01

Dissolved organic carbon (DOC) plays an important role in carbon cycling in terrestrial and aquatic systems. Stable isotope analysis (delta 13C) of DOC could provide valuable insights in its origin, fluxes and environmental fate. Precise and routine analysis of delta 13C and DOC concentration are therefore highly desirable. A promising, new system has been developed for this purpose, linking a high-temperature combustion TOC analyzer trough an interface with a continuous flow isotope ratio mass spectrometer (Elementar group, Hanau, Germany). This TOC-IRMS system enables simultaneous stable isotope (bulk delta 13C) and concentration analysis of DOC, with high oxidation efficiency by high-temperature combustion for complex mixtures as natural DOC. To give delta 13C analysis by TOC-IRMS the necessary impulse for broad-scale application, we present a detailed evaluation of its analytical performance for realistic and challenging conditions inclusive low DOC concentrations and environmental samples. High precision (standard deviation, SD predominantly < 0.15 permil) and accuracy (R2 = 0.9997, i.e. comparison TOC-IRMS and conventional EA-IRMS) were achieved by TOC-IRMS for a broad diversity of DOC solutions. This precision is comparable or even slightly better than that typically reported for EA-IRMS systems, and improves previous techniques for δ13C analysis of DOC. Simultaneously, very good precision was obtained for DOC concentration measurements. Assessment of natural abundance and slightly 13C enriched DOC, a wide range of concentrations (0.2-150 mgC/L) and injection volumes (0.05-3 ml), demonstrated good analytical performance with negligible memory effects, no concentration/volume effects and a wide linearity. Low DOC concentrations (< 2 mgC/L), were correctly analyzed without any pre-concentration. Moreover, TOC-IRMS was successfully applied to analyze DOC from diverse terrestrial, freshwater and marine environments (SD < 0.23 permil). In summary, the TOC-IRMS performs fast and reliable analysis of DOC concentration and δ13C in aqueous samples, without any pre-concentration/freeze-drying. Flexible usage is highlighted by automated, online analysis, a variable injection volume, high throughput and no extensive maintenance. Sample analysis is simple, using small aliquots and with minimal sample preparation. Further investigations should focus on complex, saline matrices and very low DOC concentrations, to achieve a potential lower limit of 0.2 mgC/L. High-resolution, routine delta 13C analysis of DOC by TOC-IRMS offers opportunities for wide-scale application in terrestrial, freshwater and marine research to elucidate the role of DOC in biogeochemical processes and ecosystem functioning.

Preclinical investigation for developing injectable fiducial markers using a mixture of BaSO{sub 4} and biodegradable polymer for proton therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Sang Hee; Gil, Moon Soo; Lee, Doo Sung

Purpose: The aim of this study is to investigate the use of mixture of BaSO{sub 4} and biodegradable polymer as an injectable nonmetallic fiducial marker to reduce artifacts in x-ray images, decrease the absorbed dose distortion in proton therapy, and replace permanent metal markers. Methods: Two samples were made with 90 wt. % polymer phosphate buffer saline (PBS) and 10 wt. % BaSO{sub 4} (B1) or 20 wt. % BaSO{sub 4} (B2). Two animal models (mice and rats) were used. To test the injectability and in vivo gelation, a volume of 200 μl at a pH 5.8 were injected intomore » the Sprague-Dawley rats. After sacrificing the rats over time, the authors checked the gel morphology. Detectability of the markers in the x-ray images was tested for two sizes (diameters of 1 and 2 mm) for B1 and B2. Four samples were injected into BALB/C mice. The polymer mixed with BaSO{sub 4} transform from SOL at 20 °C with a pH of 6.0 to GEL in the living body at 37 °C with a pH of 7.4, so the size of the fiducial marker could be controlled by adjusting the injected volume. The detectability of the BaSO{sub 4} marker was measured in x-ray images of cone beam CT (CBCT), on-board imager [anterior–posterior (AP), lateral], and fluoroscopy (AP, lateral) using a Novalis-TX (Varian Medical Systems, Palo Alto, CA) repeatedly over 4 months. The volume, HU, and artifacts for the markers were measured in the CBCT images. Artifacts were compared to those of gold marker by analyzing the HU distribution. The dose distortion in proton therapy was computed by using a Monte Carlo (MC) code. A cylindrical shaped marker (diameter: 1 or 2 mm, length: 3 mm) made of gold, stainless-steel [304], titanium, and 20 wt. % BaSO{sub 4} was positioned at the center of the spread-out Bragg peak (SOBP) in parallel or perpendicular to the beam entrance. The dose distortion was measured on the depth dose profile across the markers. Results: Transformation to GEL and the biodegradation were verified. All BaSO{sub 4} markers could be detected in the CBCT. In the OBI and fluoroscopy images, all markers visible in the AP, but only B2(2 mm) could be identified in the lateral images. Changes of BaSO{sub 4} position were not detected in vivo (mice). The volume of the markers decreased by up to 65% and the HU increased by 22%, on average. The mean HU values around the B1, B2, and gold markers were 121.30 [standard deviation (SD): 54.86], 126.31 (SD: 62.13), and 1070.7 (SD: 235.16), respectively. The MC-simulated dose distortion for the BaSO{sub 4} markers was less than that of the commercially used markers. The dose reduction due to the gold marker was largest (15.05%) followed by stainless steel (7.92%) and titanium (6.92%). Dose reduction by B2 (2 mm) was 4.75% and 0.53% in parallel and perpendicular orientations, respectively. Conclusions: BaSO{sub 4} mixed with PBS is a good contrast agent in biodegradable polymer marker because of minimal artifacts in x-ray images and minimal dose reduction in proton therapy. The flexibility of the size is considered to be an advantage of this material over solid type fiducials.« less

Determination of void volume in normal phase liquid chromatography.

PubMed

Jiang, Ping; Wu, Di; Lucy, Charles A

2014-01-10

Void volume is an important fundamental parameter in chromatography. Little prior discussion has focused on the determination of void volume in normal phase liquid chromatography (NPLC). Various methods to estimate the total void volume are compared: pycnometry; minor disturbance method based on injection of weak solvent; tracer pulse method; hold-up volume based on unretained compounds; and accessible volume based on Martin's rule and its descendants. These are applied to NPLC on silica, RingSep and DNAP columns. Pycnometry provides a theoretically maximum value for the total void volume and should be performed at least once for each new column. However, pycnometry does not reflect the volume of adsorbed strong solvent on the stationary phase, and so only yields an accurate void volume for weaker mobile phase conditions. 1,3,5-Tri-t-butyl benzene (TTBB) results in hold-up volumes that are convenient measures of the void volume for all eluent conditions on charge-transfer columns (RingSep and DNAP), but is weakly retained under weak eluent conditions on silica. Injection of the weak mobile phase component (hexane) may be used to determine void volume, but care must be exercised to select the appropriate disturbance feature. Accessible volumes, that are determined using a homologous series, are always biased low, and are not recommended as a measure of the void volume. Copyright © 2013 Elsevier B.V. All rights reserved.

Neuropathic Pain Following Poly-L-Lactic Acid (Sculptra) Injection.

PubMed

Vrcek, Ivan; El-Sawy, Tarek; Chou, Eva; Allen, Theresa; Nakra, Tanuj

Injectable fillers have become a prevalent means of facial rejuvenation and volume expansion. While typically well tolerated, serious complications have been reported. The authors present a case in which an otherwise healthy female with a history of multiple filler injections including poly-L-lactic acid, developed 3 weeks of neuropathic pain in the left temporal fossa following injection. To the best of the authors knowledge, neuropathic pain has not been reported as a complication following poly-L-lactic acid injection. The patient was treated with an injection of steroid and long-acting anesthetic with resolution of symptoms.

Petrophysical characterization of first ever drilled core samples from an active CO2 storage site, the German Ketzin Pilot Site - Comparison with long term experiments

NASA Astrophysics Data System (ADS)

Zemke, Kornelia; Liebscher, Axel

2014-05-01

Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. These parameters may change during and/or after the CO2 injection due to geochemical reactions in the reservoir system that are triggered by the injected CO2. Here we present petrophysical data of first ever drilled cores from a newly drilled well at the active CO2 storage site - the Ketzin pilot site in the Federal State of Brandenburg, Germany. By comparison with pre-injection baseline data from core samples recovered prior to injection, the new samples provide the unique opportunity to evaluate the impact of CO2 on pore size related properties of reservoir and cap rocks at a real injection site under in-situ reservoir conditions. After injection of 61 000 tons CO2, an additional well was drilled and new rock cores were recovered. In total 100 core samples from the reservoir and the overlaying caprock were investigated by NMR relaxation. Permeability of 20 core samples was estimated by nitrogen and porosity by helium pycnometry. The determined data are comparable between pre-injection and post-injection core samples. The lower part of the reservoir sandstone is unaffected by the injected CO2. The upper part of the reservoir sandstone shows consistently slightly lower NMR porosity and permeability values in the post-injection samples when compared to the pre-injection data. This upper sandstone part is above the fluid level and CO2 present as a free gas phase and a possible residual gas saturation of the cores distorted the NMR results. The potash-containing drilling fluid can also influence these results: NMR investigation of twin samples from inner and outer parts of the cores show a reduced fraction of larger pores for the outer core samples together with lower porosities and T2 times. The drill mud penetration depth can be controlled by the added fluorescent tracer. Due to the heterogeneous character of the Stuttgart Formation it is difficult to estimate definite CO2 induced changes from petrophysical measurements. The observed changes are only minor. Several batch experiments on Ketzin samples drilled prior injection confirm the results from investigation of the in-situ rock cores. Core samples of the pre-injection wells were exposed to CO2 and brine in autoclaves over various time periods. Samples were characterized prior to and after the experiments by NMR and Mercury Injection Porosimetry (MIP). The results are consistent with the logging data and show only minor change. Unfortunately, also in these experiments observed mineralogical and petrophysical changes were within the natural heterogeneity of the Ketzin reservoir and precluded unequivocal conclusions. However, given the only minor differences between post-injection well and pre-injection well, it is reasonable to assume that the potential dissolution-precipitation processes appear to have no severe consequences on reservoir and cap rock integrity or on the injection behaviour. This is also in line with the continuously recorded injection operation parameter. These do not point to any changes in reservoir injectivity.|

Petrophysical laboratory invertigations of carbon dioxide storage in a subsurface saline aquifer in Ketzin/Germany within the scope of CO2SINK

NASA Astrophysics Data System (ADS)

Zemke, K.; Kummmerow, J.; Wandrey, M.; Co2SINK Group

2009-04-01

Since June of 2008 carbon dioxide has been injected into a saline aquifer at the Ketzin test site [Würdemann et al., this volume]. The food grade CO2 is injected into a sandstone zone of the Stuttgart formation at ca. 650 m depth at 35°C reservoir temperature and 62 bar reservoir pressure. With the injection of CO2 into the geological formation, chemical and physical reservoir characteristics are changed depending on pressure, temperature, fluid chemistry and rock composition. Fluid-rock interaction could comprise dissolution of non-resistant minerals in CO2-bearing pore fluids, cementing of the pore space by precipitating substances from the pore fluid, drying and disintegration of clay minerals and thus influence of the composition and activities of the deep biosphere. To testing the injection behaviour of CO2 in water saturated rock and to evaluate the geophysical signature depending on the thermodynamic conditions, flow experiments with water and CO2 have been performed on cores of the Stuttgart formation from different locations including new wells of ketzin test site. The studied core material is an unconsolidated fine-grained sandstone with porosity values from 15 to 32 %. Permeability, electrical resistivity, and sonic wave velocities and their changes with pressure, saturation and time have been studied under simulated in situ conditions. The flow experiments conducted over several weeks with brine and CO2 showed no significant changes of resistivity and velocity and a slightly decreasing permeability. Pore fluid analysis showed mobilization of clay and some other components. A main objective of the CO2Sink laboratory program is the assessment of the effect of long-term CO2 exposure on reservoir rocks to predict the long-term behaviour of geological CO2 storage. For this CO2 exposure experiments reservoir rock samples were exposed to CO2 saturated reservoir fluid in corrosion-resistant high pressure vessels under in situ temperature and pressure conditions over a period of several months. Before and after the CO2 exposure experiment cyclic measurements of physical properties were carried out on these cores in a mechanical testing system. After experimental runs of up to 3 months no significant changes in flow and petrophysical data were observed. [For the microbilogical studies see Wandrey et al., this volume.] To study the impact of fluid-rock interactions on petrophysical parameters, porosity and pore radii distribution have been investigated before and after the experiment by NMR relaxation and mercury-injection. NMR measurements on rock core plugs saturated with brine may return valuable information on the porous structure of the rock core. The distribution of NMR-T2 values (CPMG) reflects the pore sizes within the rock core. NMR pore size is a derivative of the ratio pore surface/volume. The mercury injection pore size is an area-equivalent diameter of the throats connecting the pore system. Most of the tested samples show in the NMR measurements a slightly increasing porosity and a higher part of large pores. The mercury measurements and thin- section for microstructural characterisation after the CO2 exposure will be done at a later date.

Utilization of long duration high-volume sampling coupled to SPME-GC-MS/MS for the assessment of airborne pesticides variability in an urban area (Strasbourg, France) during agricultural application.

PubMed

Liaud, Céline; Brucher, Michel; Schummer, Claude; Coscollà, Clara; Wolff, Hélène; Schwartz, Jean-Jacques; Yusà, Vicent; Millet, Maurice

2016-10-02

Atmospheric samples have been collected between 14 March and 12 September 2012 on a 2-week basis (15 days of sampling and exchange of traps each 7 days) in Strasbourg (east of France) for the analysis of 43 pesticides. Samples (particle and gas phases) were separately extracted using Accelerated Solvent Extraction (ASE) and pre-concentrated by Solid Phase Micro-Extraction (SPME) before analysis by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Four SPME consecutive injections at distinct temperatures were made in order to increase the sensitivity of detection for the all monitored pesticides. Currently used detected pesticides can be grouped in four classes; those used in maize crops (acetochlor, benoxacor, dicamba, s-metolachlor, pendimethalin, and bromoxynil), in cereal crops (benoxacor, chlorothalonil, fenpropimorph, and propiconazole), in vineyards (tebuconazole), and as herbicides for orchards, meadows of green spaces (2,4-MCPA, trichlopyr). This is in accordance with the diversity of crops found in the Alsace region and trends observed are in accordance with the period of application of these pesticides. Variations observed permit also to demonstrate that the long time sampling duration used in this study is efficient to visualize temporal variations of airborne pesticides concentrations. Then, long time high-volume sampling could be a simple method permitting atmospheric survey of atmospheric contamination without any long analysis time and consequently low cost.

Respondent-driven sampling and the recruitment of people with small injecting networks.

PubMed

Paquette, Dana; Bryant, Joanne; de Wit, John

2012-05-01

Respondent-driven sampling (RDS) is a form of chain-referral sampling, similar to snowball sampling, which was developed to reach hidden populations such as people who inject drugs (PWID). RDS is said to reach members of a hidden population that may not be accessible through other sampling methods. However, less attention has been paid as to whether there are segments of the population that are more likely to be missed by RDS. This study examined the ability of RDS to capture people with small injecting networks. A study of PWID, using RDS, was conducted in 2009 in Sydney, Australia. The size of participants' injecting networks was examined by recruitment chain and wave. Participants' injecting network characteristics were compared to those of participants from a separate pharmacy-based study. A logistic regression analysis was conducted to examine the characteristics independently associated with having small injecting networks, using the combined RDS and pharmacy-based samples. In comparison with the pharmacy-recruited participants, RDS participants were almost 80% less likely to have small injecting networks, after adjusting for other variables. RDS participants were also more likely to have their injecting networks form a larger proportion of those in their social networks, and to have acquaintances as part of their injecting networks. Compared to those with larger injecting networks, individuals with small injecting networks were equally likely to engage in receptive sharing of injecting equipment, but less likely to have had contact with prevention services. These findings suggest that those with small injecting networks are an important group to recruit, and that RDS is less likely to capture these individuals.

Coupling model of aerobic waste degradation considering temperature, initial moisture content and air injection volume.

PubMed

Ma, Jun; Liu, Lei; Ge, Sai; Xue, Qiang; Li, Jiangshan; Wan, Yong; Hui, Xinminnan

2018-03-01

A quantitative description of aerobic waste degradation is important in evaluating landfill waste stability and economic management. This research aimed to develop a coupling model to predict the degree of aerobic waste degradation. On the basis of the first-order kinetic equation and the law of conservation of mass, we first developed the coupling model of aerobic waste degradation that considered temperature, initial moisture content and air injection volume to simulate and predict the chemical oxygen demand in the leachate. Three different laboratory experiments on aerobic waste degradation were simulated to test the model applicability. Parameter sensitivity analyses were conducted to evaluate the reliability of parameters. The coupling model can simulate aerobic waste degradation, and the obtained simulation agreed with the corresponding results of the experiment. Comparison of the experiment and simulation demonstrated that the coupling model is a new approach to predict aerobic waste degradation and can be considered as the basis for selecting the economic air injection volume and appropriate management in the future.

The Dallas-Fort Worth Airport Earthquake Sequence: Seismicity Beyond Injection Period

NASA Astrophysics Data System (ADS)

Ogwari, Paul O.; DeShon, Heather R.; Hornbach, Matthew J.

2018-01-01

The 2008 Dallas-Fort Worth Airport earthquakes mark the beginning of seismicity rate changes linked to oil and gas operations in the central United States. We assess the spatial and temporal evolution of the sequence through December 2015 using template-based waveform correlation and relative location methods. We locate 400 earthquakes spanning 2008-2015 along a basement fault mapped as the Airport fault. The sequence exhibits temporally variable b values, and small-magnitude (m < 3.4) earthquakes spread northeast along strike over time. Pore pressure diffusion models indicate that the high-volume brine injection well located within 1 km of the 2008 earthquakes, although only operating from September 2008 to August 2009, contributes most significantly to long-term pressure perturbations, and hence stress changes, along the fault; a second long-operating, low-volume injector located 10 km north causes insufficient pressure changes. High-volume injection for a short time period near a critically stressed fault can induce long-lasting seismicity.

Characterization of injected aluminum oxide nanoparticle clouds in an rf discharge

NASA Astrophysics Data System (ADS)

Krüger, Harald; Killer, Carsten; Schütt, Stefan; Melzer, André

2018-02-01

An experimental setup to deagglomerate and insert nanoparticles into a radio frequency discharge has been developed to confine defined aluminum oxide nanoparticles in a dusty plasma. For the confined particle clouds we have measured the spatially resolved in situ size and density distributions. Implementing the whole plasma chamber into the sample volume of an FTIR spectrometer the infrared spectrum of the confined aluminum oxide nanoparticles has been obtained. We have investigated the dependency of the absorbance of the nanoparticles in terms of plasma power, pressure and cloud shape. The particles’ infrared phonon resonance has been identified.

Subsurface brine injection: Proactive approach to close the produced water loop in the western desert of Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farid, E.E.; Nour, M.H.

1996-11-01

In 1988 a major onshore production facility was producing oil from eight formations in six oil fields located in the western desert of Egypt. Two of these formations include active water drive reservoirs, in addition; three reservoirs at that date were receiving water injection to enhance oil recovery. To handle the increasing volumes of the produced water (which is contaminated with oil, production chemicals and other pollutants), three alternatives were investigated: (1) Injection into disposal wells. (2) Dumping in surface disposal pits. (3) Re-injection to waterflood some oil reservoirs. The investigation revealed that the first two options are technically unfavorable,more » also they are conventional Waste Management Technologies (WMT) which provide short-term remedial solution. In contrast, Produced Water Re-Injection (PWRI) is an Environmental Control Technology (ECT) which minimize the environmental impact through process improvements. A state -of-the-art re-injection process was utilized using chemical treatment, gas liberation, settling, filtration and injection. This process represents a combination of two (ECT) methods: Reuse (for water flooding) and Recycling (when brine is redisposed underground). This process reduce the overall volumes of produced water to be disposed, increase the oil reserves, reservoir pressure and oil production and converse the underground water reserve.« less

Optimization of a therapeutic protocol for intravenous injection of human mesenchymal stem cells after cerebral ischemia in adult rats.

PubMed

Omori, Yoshinori; Honmou, Osamu; Harada, Kuniaki; Suzuki, Junpei; Houkin, Kiyohiro; Kocsis, Jeffery D

2008-10-21

The systemic injection of human mesenchymal stem cells (hMSCs) prepared from adult bone marrow has therapeutic benefits after cerebral artery occlusion in rats, and may have multiple therapeutic effects at various sites and times within the lesion as the cells respond to a particular pathological microenvironment. However, the comparative therapeutic benefits of multiple injections of hMSCs at different time points after cerebral artery occlusion in rats remain unclear. In this study, we induced middle cerebral artery occlusion (MCAO) in rats using intra-luminal vascular occlusion, and infused hMSCs intravenously at a single 6 h time point (low and high cell doses) and various multiple time points after MCAO. From MRI analyses lesion volume was reduced in all hMSC cell injection groups as compared to serum alone injections. However, the greatest therapeutic benefit was achieved following a single high cell dose injection at 6 h post-MCAO, rather than multiple lower cell infusions over multiple time points. Three-dimensional analysis of capillary vessels in the lesion indicated that the capillary volume was equally increased in all of the cell-injected groups. Thus, differences in functional outcome in the hMSC transplantation subgroups are not likely the result of differences in angiogenesis, but rather from differences in neuroprotective effects.

Forecasting magma-chamber rupture at Santorini volcano, Greece.

PubMed

Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

2015-10-28

How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011-2012 unrest period, that the measured 0.02% increase in volume of Santorini's shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano.

Identification and determination of trapping parameters as key site parameters for CO2 storage for the active CO2 storage site in Ketzin (Germany) - Comparison of different experimental approaches and analysis of field data

NASA Astrophysics Data System (ADS)

Zemke, Kornelia; Liebscher, Axel

2015-04-01

Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. The accurate quantification of residual trapping is difficult, but very important for both storage containment security and storage capacity; it is also an important parameter for dynamic simulation. The German CO2 pilot storage in Ketzin is a Triassic saline aquifer with initial conditions of the target sandstone horizon of 33.5 ° C/6.1 MPa at 630 m. One injection and two observation wells were drilled in 2007 and nearly 200 m of core material was recovered for site characterization. From June 2008 to September 2013, slightly more than 67 kt food-grade CO2 has been injected and continuously monitored. A fourth observation well has been drilled after 61 kt injected CO2 in summer 2012 at only 25 m distance to the injection well and new core material was recovered that allow study CO2 induced changes in petrophysical properties. The observed only minor differences between pre-injection and post-injection petrophysical parameters of the heterogeneous formation have no severe consequences on reservoir and cap rock integrity or on the injection behavior. Residual brine saturation for the Ketzin reservoir core material was estimated by different methods. Brine-CO2 flooding experiments for two reservoir samples resulted in 36% and 55% residual brine saturation (Kiessling, 2011). Centrifuge capillary pressure measurements (pc = 0.22 MPa) yielded the smallest residual brine saturation values with ~20% for the lower part of the reservoir sandstone and ~28% for the upper part (Fleury, 2010). The method by Cerepi (2002), which calculates the residual mercury saturation after pressure release on the imbibition path as trapped porosity and the retracted mercury volume as free porosity, yielded unrealistic low free porosity values of only a few percent, because over 80% of the penetrated mercury remained in the samples after pressure release to atmospheric pressure. The results from the centrifuge capillary pressure measurements were then used for calibrating the cutoff time of NMR T2 relaxation (average value 8 ms) to differentiate between the mobile and immobile water fraction (standard for clean sandstone 33 ms). Following Norden (2010) a cutoff time of 10 ms was applied to estimate the residual saturation as Bound Fluid Volume for the Ketzin core materials and to estimate NMR permeability after Timur-Coates. This adapted cutoff value is also consistent with results from RST logging after injection. The maximum measured CO2 saturation corresponds to the effective porosity for the upper most CO2 filled sandstone horizon. The directly measured values and the estimated residual brine saturations from NMR measurements with the adapted cutoff time of 10 ms are within the expected range compared to the literature data with a mean residual brine saturation of 53%. A. Cerepi et al., 2002, Journal of Petroleum Science and Engineering 35. M. Fleury et al., 2011, SCA2010-06. D. Kiessling et al., 2010, International Journal of Greenhouse Gas Control 4. B. Norden et al. 2010, SPE Reservoir Evaluation & Engineering 13. .

Processes Affecting the Trihalomethane Concentrations Associated with the Third Injection, Storage, and Recovery Test at Lancaster, Antelope Valley, California, March 1998 through April 1999

USGS Publications Warehouse

Fram, Miranda S.; Bergamaschi, Brian A.; Goodwin, Kelly D.; Fujii, Roger; Clark, Jordan F.

2003-01-01

The formation and fate of trihalomethanes (THM) during the third injection, storage, and recovery test at Lancaster, Antelope Valley, California, were investigated as part of a program to assess the long-term feasibility of using injection, storage, and recovery as a water-supply method and as a way to reduce water-level declines and land-subsidence in the Antelope Valley. The program was conducted by the U.S. Geological Survey in cooperation with the Los Angeles County Department of Public Works and the Antelope Valley-East Kern Water Agency. The water used for injection, storage, and recovery must be disinfected before injection and thus contains THMs and other disinfection by-products. THMs (chloroform, CHCl3, bromodichloromethane, CHCl2Br, dibromochloromethane, CHClBr2, and bromoform, CHBr3) are formed by reaction between natural dissolved organic carbon that is present in water and chlorine that is added during the disinfection step of the drinking water treatment process. THMs are carcinogenic compounds, and their concentrations in drinking water are regulated by the U.S. Environmental Protection Agency. During previous cycles of the Lancaster program, extracted water still contained measurable concentrations of THMs long after continuous pumping had extracted a greater volume of water than had been injected. This raised concerns about the potential long-term effect of injection, storage, and recovery cycles on ground-water quality in Antelope Valley aquifers. The primary objectives of this investigation were to determine (1) what controlled continued THM formation in the aquifer after injection, (2) what caused of the persistence of THMs in the extracted water, even after long periods of pumping, (3) what controlled the decrease of THM concentrations during the extraction period, and (4) the potential for natural attenuation of THMs in the aquifer. Laboratory experiments on biodegradation of THMs in microcosms of aquifer materials indicate that aquifer bacteria did not degrade CHCl3 or CHBr3 under aerobic conditions, but did degrade CHBr3 under anaerobic conditions. However, the aquifer is naturally aerobic and CHCl3 is the dominant THM species; therefore, biodegradation is not considered an important attenuation mechanism for THMs in this aquifer. The alluvial-fan sediments comprising the aquifer have very low contents of organic matter; therefore, sorption is not considered to be an important attenuation mechanism for THMs in this aquifer. Laboratory experiments on formation of THMs in the injection water indicate that continued THM formation in the injection water after injection into the aquifer was limited by the amount of residual chlorine in the injection water at the time of injection. After accounting for THMs formed by reaction of this residual chlorine, THMs behaved as conservative constituents in the aquifer, and the only process affecting the concentration of THMs was mixing of the injection water and the ground water. The mixing process was quantified using mass balances of injected constituents, the sulfur hexafluoride (SF6) tracer that was added to the injected water, and a simple descriptive mathematical mixing model. Mass balance calculations show that only 67 percent of the injected THMs and chloride were recovered by the time that a volume of water equivalent to 132 percent of the injection water volume was extracted. Pumping 250 percent of the injection water volume only increased recovery of injected THMs to 80 percent. THM and SF6 concentrations in the extracted water decreased concomitantly during the extraction period, and THM concentrations predicted from SF6 concentrations closely matched the measured THM concentrations. Because SF6 is a conservative tracer that was initially only present in the injection water, parallel decreases in SF6 and THM concentrations in the extracted water must be due to dilution of injection water with ground water. The simple descriptive mixing mode

Polymers And Riblets Reduce Hydrodynamic Skin Friction

NASA Technical Reports Server (NTRS)

Bushnell, Dennis M.; Reed, Jason C.

1991-01-01

Polymers injected into riblet grooves dramatically reduce polymer flow rate required for drag reduction. Polymer solution injected into valleys of grooves through array of holes or slots angled downstream to keep injected streams within grooves. Injection repeated some distance downstream because volumes of grooves finite and polymer becomes depleted as slowly pulled from groove by turbulence. Potentially useful for oil tankers as means of markedly reducing cost of fuel and used extensively on submarines, other ships, and other marine vehicles.

Modeling of CO 2 sequestration in coal seams: Role of CO 2 -induced coal softening on injectivity, storage efficiency and caprock deformation: Original Research Article: Modeling of CO 2 sequestration in coal seams

DOE PAGES

Ma, Tianran; Rutqvist, Jonny; Liu, Weiqun; ...

2017-01-30

An effective and safe operation for sequestration of CO 2 in coal seams requires a clear understanding of injection-induced coupled hydromechanical processes such as the evolution of pore pressure, permeability, and induced caprock deformation. In this study, CO 2 injection into coal seams was studied using a coupled flow-deformation model with a new stress-dependent porosity and permeability model that considers CO 2 -induced coal softening. Based on triaxial compression tests of coal samples extracted from the site of the first series of enhanced coalbed methane field tests in China, a softening phenomenon that a substantial (one-order-of-magnitude) decrease of Young's modulusmore » and an increase of Poisson's ratio with adsorbed CO 2 content was observed. Such softening was considered in the numerical simulation through an exponential relation between elastic properties (Young's modulus and Poisson's ratio) and CO 2 pressure considering that CO 2 content is proportional to the CO 2 pressure. Our results of the numerical simulation show that the softening of the coal strongly affects the CO 2 sequestration performance, first by impeding injectivity and stored volume (cumulative injection) during the first week of injection, and thereafter by softening mediated rebound in permeability that tends to increase injectivity and storage over the longer term. A sensitivity study shows that stronger CO 2 -induced coal softening and higher CO 2 injection pressure contribute synergistically to increase a significant increase of CO 2 injectivity and adsorption, but also result in larger caprock deformations and uplift. This study demonstrates the importance of considering the CO 2 -induced softening when analyzing the performance and environmental impact of CO 2 -sequestration operations in unminable coal seams.« less

Modeling of CO 2 sequestration in coal seams: Role of CO 2 -induced coal softening on injectivity, storage efficiency and caprock deformation: Original Research Article: Modeling of CO 2 sequestration in coal seams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Tianran; Rutqvist, Jonny; Liu, Weiqun

An effective and safe operation for sequestration of CO 2 in coal seams requires a clear understanding of injection-induced coupled hydromechanical processes such as the evolution of pore pressure, permeability, and induced caprock deformation. In this study, CO 2 injection into coal seams was studied using a coupled flow-deformation model with a new stress-dependent porosity and permeability model that considers CO 2 -induced coal softening. Based on triaxial compression tests of coal samples extracted from the site of the first series of enhanced coalbed methane field tests in China, a softening phenomenon that a substantial (one-order-of-magnitude) decrease of Young's modulusmore » and an increase of Poisson's ratio with adsorbed CO 2 content was observed. Such softening was considered in the numerical simulation through an exponential relation between elastic properties (Young's modulus and Poisson's ratio) and CO 2 pressure considering that CO 2 content is proportional to the CO 2 pressure. Our results of the numerical simulation show that the softening of the coal strongly affects the CO 2 sequestration performance, first by impeding injectivity and stored volume (cumulative injection) during the first week of injection, and thereafter by softening mediated rebound in permeability that tends to increase injectivity and storage over the longer term. A sensitivity study shows that stronger CO 2 -induced coal softening and higher CO 2 injection pressure contribute synergistically to increase a significant increase of CO 2 injectivity and adsorption, but also result in larger caprock deformations and uplift. This study demonstrates the importance of considering the CO 2 -induced softening when analyzing the performance and environmental impact of CO 2 -sequestration operations in unminable coal seams.« less

Injectable tissue-engineered cartilage using commercially available fibrin glue.

PubMed

Cakmak, Ozcan; Babakurban, Seda T; Akkuzu, Hatice G; Bilgi, Selcuk; Ovalı, Ercüment; Kongur, Merve; Altintas, Hande; Yilmaz, Bayram; Bilezikçi, Banu; Celik, Zerrin Y; Yakicier, Mustafa C; Sahin, Feride I

2013-12-01

To achieve injectable tissue-engineered cartilage using a commercially available fibrin sealant, and to determine the most suitable fibrin glue concentration, cartilage source, and cultured chondrocyte concentration. Animal research. A total of 28 immunocompetent New Zealand white rabbits were divided into four groups. The cultured chondrocytes from different anatomical sources carried in fibrin glue with and without aprotinin in different concentrations of fibrinogen and thrombin (Tisseell), were injected into forehead and interocular regions of the rabbits. The new tissue formation was harvested at 8 weeks and analyzed through gross and histological analysis. The new tissue formations were found in round, elliptical, and flat forms. The mean value of Tisseell and cell suspension was 0.8 cc in all of the rabbits' injection regions, but the mean volume of the samples in which immature cartilage matrix and mature cartilage was 0.1 cc. In the 20 of the 55 injection regions of rabbits (36, 36%), mature and/or immature cartilage formation were observed. We observed inflammatory reactions, abscess formation, and foreign body reactions around the new cartilage tissue of tissue-engineered cartilage. The comparison of results using different cartilage sources, chondrocyte concentrations, or different fibrin glue concentrations did not show any significant difference. We observed that changing the concentrations of ingredients of commercially available fibrin glue, the source of the cartilage, or the cultured chondrocyte concentration did not have significant effect on neocartilage formation. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Minimum effective volume of mepivacaine for ultrasound-guided supraclavicular block

PubMed Central

Song, Jae Gyok; Kang, Bong Jin; Park, Kee Keun

2013-01-01

Background The aim of this study was to estimate the minimum effective volume (MEV) of 1.5% mepivacaine for ultrasound-guided supraclavicular block by placing the needle near the lower trunk of brachial plexus and multiple injections. Methods Thirty patients undergoing forearm and hand surgery received ultrasound-guided supraclavicular block with 1.5% mepivacaine. The initial volume of local anesthetic injected was 24 ml, and local anesthetic volume for the next patient was determined by the response of the previous patient. The next patient received a 3 ml higher volume in the case of the failure of the previous case. If the previous block was successful, the next volume was 3 ml lower. MEV was estimated by the Dixon and Massey up and down method. MEV in 95, 90, and 50% of patients (MEV95, MEV90, and MEV50) were calculated using probit transformation and logistic regression. Results MEV95 of 1.5% mepivacaine was 17 ml (95% confidence interval [CI], 13-42 ml), MEV90 was 15 ml (95% CI, 12-34 ml), and MEV50 was 9 ml (95% CI, 4-12 ml). Twelve patients had a failed block. Three patients received general anesthesia. Nine patients could undergo surgery with sedation only. Only one patient showed hemi-diaphragmatic paresis. Conclusions MEV95 was 17 ml, MEV90 was 15 ml, and MEV50 was 9 ml. However, needle location near the lower trunk of brachial plexus and multiple injections should be performed. PMID:23904937

Ultrasound assessment of cranial spread during caudal blockade in children: the effect of different volumes of local anaesthetics.

PubMed

Brenner, L; Marhofer, P; Kettner, S C; Willschke, H; Machata, A-M; Al-Zoraigi, U; Lundblad, M; Lönnqvist, P A

2011-08-01

Despite the large amount of literature on caudal anaesthesia in children, the issue of volume of local anaesthetics and cranial spread is still not settled. Thus, the aim of the present prospective randomized study was to evaluate the cranial spread of caudally administered local anaesthetics in children by means of real-time ultrasound, with a special focus on the effects of using different volumes of local anaesthetics. Seventy-five children, 1 month to 6 yr, undergoing inguinal hernia repair or more distal surgery were randomized to receive a caudal block with 0.7, 1.0, or 1.3 ml kg(-1) ropivacaine. The cranial spread of the local anaesthetic within the spinal canal was assessed by real-time ultrasound scanning; the absolute cranial segmental level and the cranial level relative to the conus medullaris were determined. All the blocks were judged to be clinically successful. A significant correlation was found between the injected volume and the cranial level reached by the local anaesthetic both with regards to the absolute cranial segmental level and the cranial level relative to the conus medullaris. The main finding of the present study was positive, but numerically small correlation between injected volumes of local anaesthetic and the cranial spread of caudally administered local anaesthetics. Therefore, the prediction of the cranial spread of local anaesthetic, depending on the injected volume of the local anaesthetic, was not possible. EudraCT Number: 2008-007627-40.

Simplex optimization of the variables influencing the determination of pefloxacin by time-resolved chemiluminescence

NASA Astrophysics Data System (ADS)

Murillo Pulgarín, José A.; Alañón Molina, Aurelia; Jiménez García, Elisa

2018-03-01

A new chemiluminescence (CL) detection system combined with flow injection analysis (FIA) for the determination of Pefloxacin is proposed. The determination is based on an energy transfer from Pefloxacin to terbium (III). The metal ion enhances the weak CL signal produced by the KMnO4/H2SO3/Pefloxacin system. A modified simplex method was used to optimize chemical and instrumental variables. The influence of the interaction of the permanganate, Tb (III), sodium sulphite and sulphuric acid concentrations, flow rate and injected sample volume was thoroughly investigated by using a modified simplex optimization procedure. The results revealed a strong direct relationship between flow rate and CL intensity throughout the studied range that was confirmed by a gamma test. The response factor for the CL emission intensity was used to assess performance in order to identify the optimum conditions for maximization of the response. Under such conditions, the CL response was proportional to the Pefloxacin concentration over a wide range. The detection limit as calculated according to Clayton's criterion 13.7 μg L- 1. The analyte was successfully determined in milk samples with an average recovery of 100.6 ± 9.8%.

Enhancement of indirect sulphation of limestone by steam addition.

PubMed

Stewart, Michael C; Manovic, Vasilije; Anthony, Edward J; Macchi, Arturo

2010-11-15

The effect of water (H₂O(g)) on in situ SO₂ capture using limestone injection under (FBC) conditions was studied using a thermobalance and tube furnace. The indirect sulphation reaction was found to be greatly enhanced in the presence of H₂O(g). Stoichiometric conversion of samples occurred when sulphated with a synthetic flue gas containing 15% H₂O(g) in under 10 h, which is equivalent to a 45% increase in conversion as compared to sulphation without H₂O(g). Using gas pycnometry and nitrogen adsorption methods, it was shown that limestone samples sulphated in the presence of H₂O(g) undergo increased particle densification without any significant changes to pore area or volume. The microstructural changes and observed increase in conversion were attributed to enhanced solid-state diffusion in CaO/CaSO₄ in the presence of H₂O(g). Given steam has been shown to have such a strong influence on sulphation, whereas it had been previously regarded as inert, may prompt a revisiting of the classically accepted sulphation models and phenomena. These findings also suggest that steam injection may be used to enhance sulfur capture performance in fluidized beds firing low-moisture fuels such as petroleum coke.

Sequential Blood Filtration for Extracorporeal Circulation: Initial Results from a Proof-of-Concept Prototype.

PubMed

Herbst, Daniel P

2014-09-01

Micropore filters are used during extracorporeal circulation to prevent gaseous and solid particles from entering the patient's systemic circulation. Although these devices improve patient safety, limitations in current designs have prompted the development of a new concept in micropore filtration. A prototype of the new design was made using 40-μm filter screens and compared against four commercially available filters for performance in pressure loss and gross air handling. Pre- and postfilter bubble counts for 5- and 10-mL bolus injections in an ex vivo test circuit were recorded using a Doppler ultrasound bubble counter. Statistical analysis of results for bubble volume reduction between test filters was performed with one-way repeated-measures analysis of variance using Bonferroni post hoc tests. Changes in filter performance with changes in microbubble load were also assessed with dependent t tests using the 5- and 10-mL bolus injections as the paired sample for each filter. Significance was set at p < .05. All filters in the test group were comparable in pressure loss performance, showing a range of 26-33 mmHg at a flow rate of 6 L/min. In gross air-handling studies, the prototype showed improved bubble volume reduction, reaching statistical significance with three of the four commercial filters. All test filters showed decreased performance in bubble volume reduction when the microbubble load was increased. Findings from this research support the underpinning theories of a sequential arterial-line filter design and suggest that improvements in microbubble filtration may be possible using this technique.

Sequential Blood Filtration for Extracorporeal Circulation: Initial Results from a Proof-of-Concept Prototype

PubMed Central

Herbst, Daniel P.

2014-01-01

Abstract: Micropore filters are used during extracorporeal circulation to prevent gaseous and solid particles from entering the patient’s systemic circulation. Although these devices improve patient safety, limitations in current designs have prompted the development of a new concept in micropore filtration. A prototype of the new design was made using 40-μm filter screens and compared against four commercially available filters for performance in pressure loss and gross air handling. Pre- and postfilter bubble counts for 5- and 10-mL bolus injections in an ex vivo test circuit were recorded using a Doppler ultrasound bubble counter. Statistical analysis of results for bubble volume reduction between test filters was performed with one-way repeated-measures analysis of variance using Bonferroni post hoc tests. Changes in filter performance with changes in microbubble load were also assessed with dependent t tests using the 5- and 10-mL bolus injections as the paired sample for each filter. Significance was set at p < .05. All filters in the test group were comparable in pressure loss performance, showing a range of 26–33 mmHg at a flow rate of 6 L/min. In gross air-handling studies, the prototype showed improved bubble volume reduction, reaching statistical significance with three of the four commercial filters. All test filters showed decreased performance in bubble volume reduction when the microbubble load was increased. Findings from this research support the underpinning theories of a sequential arterial-line filter design and suggest that improvements in microbubble filtration may be possible using this technique. PMID:26357790

Pathophysiology of infantile pulmonary arterial hypertension induced by monocrotaline.

PubMed

Dias-Neto, Marina; Luísa-Neves, Ana; Pinho, Sónia; Gonçalves, Nádia; Mendes, Maria; Eloy, Catarina; Lopes, José M; Gonçalves, Daniel; Ferreira-Pinto, Manuel; Leite-Moreira, Adelino F; Henriques-Coelho, Tiago

2015-06-01

Pediatric pulmonary arterial hypertension (PAH) presents certain specific features. In this specific age group, experimental models to study the pathophysiology of PAH are lacking. To characterize hemodynamic, morphometric, and histological progression as well as the expression of neurohumoral factors and regulators of cardiac transcription in an infantile model of PAH induced by monocrotaline (MCT), eight-day-old Wistar rats were randomly injected with MCT (30 mg/kg, sc, n = 95) or equal volume of saline solution (n = 92). Animals were instrumented for biventricular hemodynamic recording 7, 14, and 21 days after MCT, whereas samples were collected at 1, 3, 7, 14, and 21 days after MCT. Different time point postinjections were defined for further analysis. Hearts and lungs were collected for morphometric characterization, assessment of right- and left-ventricle (RV and LV) cardiomyocyte diameter and collagen type-I and type-III ratio, RV collagen volume fraction, and pulmonary vessels wall thickness. mRNA quantification was undertaken for brain natriuretic peptide (BNP), endothelin-1 (ET-1), and for cardiac transcription regulators (HOP and Islet1). Animals treated with MCT at the 8th day of life presented RV hypertrophy since day 14 after MCT injection. There were no differences on the RV collagen volume fraction or collagen type-I and type-III ratio. Pulmonary vascular remodelling and PAH were present on day 21, which were accompanied by an increased expression of BNP, ET-1, HOP, and Islet1. The infantile model of MCT-induced PAH can be useful for the study of its pathophysiology and to test new therapeutic targets in pediatric age group.

Characterization of Radium and Radon Isotopes in Hydraulic Fracturing Flowback Fluid and Gas from the Marcellus Shale

NASA Astrophysics Data System (ADS)

Bardsley, A.

2015-12-01

High volume hydraulic fracturing of unconventional deposits has expanded rapidly over the past decade in the US, with much attention focused on the Marcellus Shale gas reservoir in the northeastern US. We use naturally occurring radium isotopes and 222Rn to explore changes in formation characteristics as a result of hydraulic fracturing. Gas and produced waters were analyzed from time series samples collected soon after hydraulic fracturing at three Marcellus Shale well sites in the Appalachian Basin, USA. Analyses of δ18O, Cl- , and 226Ra in flowback fluid are consistent with two end member mixing between injected slick water and formation brine. All three tracers indicate that the ratio of injected water to formation brine declines with time across both time series. Cl- concentration (max ~1.5-2.2 M) and 226Ra activity (max ~165-250 Bq/Kg) in flowback fluid are comparable at all three sites. There are differences evident in the stable isotopic composition (δ18O & δD) of injected slick water across the three sites, but all appear to mix with formation brine of similar isotopic composition. On a plot of water isotopes, δ18O in formation brine-dominated fluid is enriched by ~3-4 permille relative to the Global Meteoric Water Line, indicating oxygen exchange with shale. The ratio of 223Ra/226Ra and 228Ra/226Ra in produced waters is quite low relative to shale samples analyzed. This indicates that most of the 226Ra in the formation brine must be sourced from shale weathering or dissolution rather than emanation due to alpha recoil from the rock surface. During the first week of flowback, ratios of short lived isotopes 223Ra and 224Ra to longer lived radium isotopes change modestly, suggesting rock surface area per unit of produced water volume did not change substantially. For one well, longer term gas samples were collected. The 222Rn/methane ratio in produced gas from this site declines with time and may represent a decrease in the brine to gas ratio in the reservoir over the course of six months after initial fracturing. Naturally occurring radium and radon isotopes show promise in elucidating sub-surface dynamics following hydraulic fracturing plays.

THE REAL ESTATE OF MYOBLAST CARDIAC TRANSPLANTATION – NEGATIVE REMODELING IS ASSOCIATED WITH LOCATION

PubMed Central

McCue, Jonathan D.; Swingen, Cory; Feldberg, Tanya; Caron, Gabe; Kolb, Adam; Denucci, Christopher; Prabhu, Somnath; Motilall, Randy; Breviu, Brian; Taylor, Doris A.

2009-01-01

Background Skeletal myoblast (SKMB) transplantation has been proposed as a therapy for ischemic cardiomyopathy due to its possible role in myogenesis. The relative safety and efficacy based on location within scar is not known. We hypothesized that SKMB transplanted into peripheral scar (compared to central scar) would more effectively attenuate negative left ventricular (LV) remodeling but at the risk of arrhythmia. Methods 34 New Zealand White rabbits underwent mid-left anterior descending artery (LAD) ligation to produce a transmural LV infarction. One month after LAD ligation SKMBs were injected either in the scar center (n=13) or scar periphery (n=10) and compared to saline injection (n=11). Holter monitoring and MRI was performed pre-injection; Holter monitoring was continued until two weeks post injection, with follow-up MRI at one month. Results Centrally-treated animals demonstrated increased LV end systolic volume, end diastolic volume and mass that correlated with injected cell number. There was a trend toward attenuation of negative LV remodeling in peripherally-treated animals compared to vehicle. Significant late ectopy was seen in several centrally-injected animals with no late ectopy seen in peripherally-injected animals. Conclusions We noted untoward effects with respect to negative LV remodeling following central injection, suggesting that transplanted cell location with respect to scar may be a key factor in the safety and efficacy of SKMB cardiac transplantation. Administration of SKMBs into peripheral scar appears safe with a trend toward improved function in comparison to sham injection. PMID:18187097

Indirect MR lymphangiography of the head and neck using conventional gadolinium contrast: A pilot study in humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loo, Billy W.; Draney, Mary T.; Sivanandan, Ranjiv

2006-10-01

Purpose: To evaluate indirect magnetic resonance lymphangiography (MR-LAG) using interstitial injection of conventional gadolinium contrast (gadoteridol and gadopentetate dimeglumine) for delineating the primary lymphatic drainage of head-and-neck sites. Methods and Materials: We performed head-and-neck MR-LAG in 5 healthy volunteers, with injection of dermal and mucosal sites. We evaluated the safety of the procedure, the patterns of enhancement categorized by injection site and nodal level, the time course of enhancement, the optimal concentration and volume of contrast, and the optimal imaging sequence. Results: The worst side effects of interstitial contrast injection were brief, mild pain and swelling at the injected sitesmore » that were self-limited. MR-LAG resulted in consistent visualization of the primary lymphatic drainage pattern specific to each injected site, which was reproducible on repeated examinations. The best enhancement was obtained with injection of small volumes (0.3-0.5 mL) of either agent diluted, imaging within 5-15 min of injection, and a three-dimensional fast spoiled gradient echo sequence with magnetization transfer. Conclusions: We found head-and-neck MR-LAG to be a safe, convenient imaging method that provides functional information about the lymphatic drainage of injected sites. Applied to head-and-neck cancer, it has the potential to identify sites at highest risk of occult metastatic spread for radiotherapy or surgical planning, and possibly to visualize micrometastases.« less

The effects of varying injection rates in Osage County, Oklahoma, on the 2016 Mw5.8 Pawnee earthquake

USGS Publications Warehouse

Barbour, Andrew J.; Norbeck, Jack H.; Rubinstein, Justin L.

2017-01-01

The 2016 Mw 5.8 Pawnee earthquake occurred in a region with active wastewater injection into a basal formation group. Prior to the earthquake, fluid injection rates at most wells were relatively steady, but newly collected data show significant increases in injection rate in the years leading up to earthquake. For the same time period, the total volumes of injected wastewater were roughly equivalent between variable‐rate and constant‐rate wells. To understand the possible influence of these changes in injection, we simulate the variable‐rate injection history and its constant‐rate equivalent in a layered poroelastic half‐space to explore the interplay between pore‐pressure effects and poroelastic effects on the fault leading up to the mainshock. In both cases, poroelastic stresses contribute a significant proportion of Coulomb failure stresses on the fault compared to pore‐pressure increases alone, but the resulting changes in seismicity rate, calculated using a rate‐and‐state frictional model, are many times larger when poroelastic effects are included, owing to enhanced stressing rates. In particular, the variable‐rate simulation predicts more than an order of magnitude increase in seismicity rate above background rates compared to the constant‐rate simulation with equivalent volume. The observed cumulative density of earthquakes prior to the mainshock within 10 km of the injection source exhibits remarkable agreement with seismicity predicted by the variable‐rate injection case.

Hierarchical Cluster Analysis of Three-Dimensional Reconstructions of Unbiased Sampled Microglia Shows not Continuous Morphological Changes from Stage 1 to 2 after Multiple Dengue Infections in Callithrix penicillata

PubMed Central

Diniz, Daniel G.; Silva, Geane O.; Naves, Thaís B.; Fernandes, Taiany N.; Araújo, Sanderson C.; Diniz, José A. P.; de Farias, Luis H. S.; Sosthenes, Marcia C. K.; Diniz, Cristovam G.; Anthony, Daniel C.; da Costa Vasconcelos, Pedro F.; Picanço Diniz, Cristovam W.

2016-01-01

It is known that microglial morphology and function are related, but few studies have explored the subtleties of microglial morphological changes in response to specific pathogens. In the present report we quantitated microglia morphological changes in a monkey model of dengue disease with virus CNS invasion. To mimic multiple infections that usually occur in endemic areas, where higher dengue infection incidence and abundant mosquito vectors carrying different serotypes coexist, subjects received once a week subcutaneous injections of DENV3 (genotype III)-infected culture supernatant followed 24 h later by an injection of anti-DENV2 antibody. Control animals received either weekly anti-DENV2 antibodies, or no injections. Brain sections were immunolabeled for DENV3 antigens and IBA-1. Random and systematic microglial samples were taken from the polymorphic layer of dentate gyrus for 3-D reconstructions, where we found intense immunostaining for TNFα and DENV3 virus antigens. We submitted all bi- or multimodal morphological parameters of microglia to hierarchical cluster analysis and found two major morphological phenotypes designated types I and II. Compared to type I (stage 1), type II microglia were more complex; displaying higher number of nodes, processes and trees and larger surface area and volumes (stage 2). Type II microglia were found only in infected monkeys, whereas type I microglia was found in both control and infected subjects. Hierarchical cluster analysis of morphological parameters of 3-D reconstructions of random and systematic selected samples in control and ADE dengue infected monkeys suggests that microglia morphological changes from stage 1 to stage 2 may not be continuous. PMID:27047345

Hierarchical Cluster Analysis of Three-Dimensional Reconstructions of Unbiased Sampled Microglia Shows not Continuous Morphological Changes from Stage 1 to 2 after Multiple Dengue Infections in Callithrix penicillata.

PubMed

Diniz, Daniel G; Silva, Geane O; Naves, Thaís B; Fernandes, Taiany N; Araújo, Sanderson C; Diniz, José A P; de Farias, Luis H S; Sosthenes, Marcia C K; Diniz, Cristovam G; Anthony, Daniel C; da Costa Vasconcelos, Pedro F; Picanço Diniz, Cristovam W

2016-01-01

It is known that microglial morphology and function are related, but few studies have explored the subtleties of microglial morphological changes in response to specific pathogens. In the present report we quantitated microglia morphological changes in a monkey model of dengue disease with virus CNS invasion. To mimic multiple infections that usually occur in endemic areas, where higher dengue infection incidence and abundant mosquito vectors carrying different serotypes coexist, subjects received once a week subcutaneous injections of DENV3 (genotype III)-infected culture supernatant followed 24 h later by an injection of anti-DENV2 antibody. Control animals received either weekly anti-DENV2 antibodies, or no injections. Brain sections were immunolabeled for DENV3 antigens and IBA-1. Random and systematic microglial samples were taken from the polymorphic layer of dentate gyrus for 3-D reconstructions, where we found intense immunostaining for TNFα and DENV3 virus antigens. We submitted all bi- or multimodal morphological parameters of microglia to hierarchical cluster analysis and found two major morphological phenotypes designated types I and II. Compared to type I (stage 1), type II microglia were more complex; displaying higher number of nodes, processes and trees and larger surface area and volumes (stage 2). Type II microglia were found only in infected monkeys, whereas type I microglia was found in both control and infected subjects. Hierarchical cluster analysis of morphological parameters of 3-D reconstructions of random and systematic selected samples in control and ADE dengue infected monkeys suggests that microglia morphological changes from stage 1 to stage 2 may not be continuous.

Maximum magnitude estimations of induced earthquakes at Paradox Valley, Colorado, from cumulative injection volume and geometry of seismicity clusters

NASA Astrophysics Data System (ADS)

Yeck, William L.; Block, Lisa V.; Wood, Christopher K.; King, Vanessa M.

2015-01-01

The Paradox Valley Unit (PVU), a salinity control project in southwest Colorado, disposes of brine in a single deep injection well. Since the initiation of injection at the PVU in 1991, earthquakes have been repeatedly induced. PVU closely monitors all seismicity in the Paradox Valley region with a dense surface seismic network. A key factor for understanding the seismic hazard from PVU injection is the maximum magnitude earthquake that can be induced. The estimate of maximum magnitude of induced earthquakes is difficult to constrain as, unlike naturally occurring earthquakes, the maximum magnitude of induced earthquakes changes over time and is affected by injection parameters. We investigate temporal variations in maximum magnitudes of induced earthquakes at the PVU using two methods. First, we consider the relationship between the total cumulative injected volume and the history of observed largest earthquakes at the PVU. Second, we explore the relationship between maximum magnitude and the geometry of individual seismicity clusters. Under the assumptions that: (i) elevated pore pressures must be distributed over an entire fault surface to initiate rupture and (ii) the location of induced events delineates volumes of sufficiently high pore-pressure to induce rupture, we calculate the largest allowable vertical penny-shaped faults, and investigate the potential earthquake magnitudes represented by their rupture. Results from both the injection volume and geometrical methods suggest that the PVU has the potential to induce events up to roughly MW 5 in the region directly surrounding the well; however, the largest observed earthquake to date has been about a magnitude unit smaller than this predicted maximum. In the seismicity cluster surrounding the injection well, the maximum potential earthquake size estimated by these methods and the observed maximum magnitudes have remained steady since the mid-2000s. These observations suggest that either these methods overpredict maximum magnitude for this area or that long time delays are required for sufficient pore-pressure diffusion to occur to cause rupture along an entire fault segment. We note that earthquake clusters can initiate and grow rapidly over the course of 1 or 2 yr, thus making it difficult to predict maximum earthquake magnitudes far into the future. The abrupt onset of seismicity with injection indicates that pore-pressure increases near the well have been sufficient to trigger earthquakes under pre-existing tectonic stresses. However, we do not observe remote triggering from large teleseismic earthquakes, which suggests that the stress perturbations generated from those events are too small to trigger rupture, even with the increased pore pressures.

Method development for the analysis of N-nitrosodimethylamine and other N-nitrosamines in drinking water at low nanogram/liter concentrations using solid-phase extraction and gas chromatography with chemical ionization tandem mass spectrometry.

PubMed

Munch, Jean W; Bassett, Margarita V

2006-01-01

N-nitrosodimethylamine (NDMA) is a probable human carcinogen of concern that has been identified as a drinking water contaminant. U.S. Environmental Protection Agency Method 521 has been developed for the analysis of NDMA and 6 additional N-nitrosamines in drinking water at low ng/L concentrations. The method uses solid-phase extraction with coconut charcoal as the sorbent and dichloromethane as the eluent to concentrate 0.50 L water samples to 1 mL. The extracts are analyzed by gas chromatography-chemical ionization tandem mass spectrometry using large-volume injection. Method performance was evaluated in 2 laboratories. Typical analyte recoveries of 87-104% were demonstrated for fortified reagent water samples, and recoveries of 77-106% were demonstrated for fortified drinking water samples. All relative standard deviations on replicate analyses were < 11%.

Laboratory Study of the Displacement Coalbed CH4 Process and Efficiency of CO2 and N2 Injection

PubMed Central

Wang, Liguo; Wang, Yongkang

2014-01-01

ECBM displacement experiments are a direct way to observe the gas displacement process and efficiency by inspecting the produced gas composition and flow rate. We conducted two sets of ECBM experiments by injecting N2 and CO2 through four large parallel specimens (300 × 50 × 50 mm coal briquette). N2 or CO2 is injected at pressures of 1.5, 1.8, and 2.2 MPa and various crustal stresses. The changes in pressure along the briquette and the concentration of the gas mixture flowing out of the briquette were analyzed. Gas injection significantly enhances CBM recovery. Experimental recoveries of the original extant gas are in excess of 90% for all cases. The results show that the N2 breakthrough occurs earlier than the CO2 breakthrough. The breakthrough time of N2 is approximately 0.5 displaced volumes. Carbon dioxide, however, breaks through at approximately 2 displaced volumes. Coal can adsorb CO2, which results in a slower breakthrough time. In addition, ground stress significantly influences the displacement effect of the gas injection. PMID:24741346

Anatomical Basis for Safe and Effective Volumization of the Temple.

PubMed

Breithaupt, Andrew D; Jones, Derek H; Braz, Andre; Narins, Rhoda; Weinkle, Susan

2015-12-01

One of the earliest but often unaddressed signs of facial aging is volume loss in the temple. Treatment of the area can produce satisfying results for both patient and practitioner. Safe injection requires explicit knowledge of the anatomy to avoid complications related to the multitude of vessels that course throughout the region at various depths. The authors aim to detail the anatomy of the area and provide a safe and easy-to-follow method for injection. The authors review the relevant anatomy of the temporal region and its application to cosmetic filler injections. The authors describe an easy-to-follow approach for a safe and effective injection window based on numerous anatomical studies. Injection in this area is not without risk, including potential blindness. The authors review the potential complications and their treatments. Hollowing of the temple is an early sign of aging that, when corrected, can lead to significant patient and practitioner satisfaction. Proper anatomically knowledge is required to avoid potentially severe complications. In this study, the authors present a reliable technique to safely and effectively augment this often undertreated area of the aging face.

Migration rates and formation injectivity to determine containment time scales of sequestered carbon dioxide

USGS Publications Warehouse

Burke, Lauri

2012-01-01

Additionally, this research establishes a methodology to calculate the injectivity of a target formation. Because injectivity describes the pressure increase due to the introduction of fluids into a formation, the relevant application of injectivity is to determine the pressure increase, due to an injection volume and flow rate, that will induce fractures in the reservoir rocks. This quantity is defined mathematically as the maximum pressure differential between the hydrostatic gradient and the fracture gradient of the target formation. Injectivity is mathematically related to the maximum pressure differential of the formation, and can be used to determine the upper limit for the pressure increase that an injection target can withstand before fracturing.

Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

NASA Astrophysics Data System (ADS)

Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

2018-04-01

To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

Design of a microfluidic sensor for high-sensitivity Copper (II) sensing applications

NASA Astrophysics Data System (ADS)

Gibson, Ceri; Byrne, Patrick; Gray, David; MacCraith, Brian D.; Paull, Brett; Tyrrell, Eadaoin

2003-03-01

An all-plastic micro-sensor system for remote measurement of copper (II) ions in the aqueous environment has been developed. The sensing structure was designed for ease of milling and fabricated in poly (methyl methacrylate) (PMMA) using a hot-embossing technique. Issues of sealing the structure were studied extensively and an efficient protocol has been established. The detection system comprises a compact photo-multiplier tube and integrated photon counting system. This method has advantages of low sample volume, (creating a minimal volume of waste), low exposure to contaminants due to the closed system, no moving parts and employs a robust polymer material which is resistant to the environment of intended use. The sensor operates on the principle of flow injection analysis and has been tested using a chemiluminescence (FIA-CL) reaction arising from the complexation of copper with 1,10-phenanthroline and subsequent oxidation by hydrogen peroxide.

How metalliferous brines line Mexican epithermal veins with silver

PubMed Central

Wilkinson, Jamie J.; Simmons, Stuart F.; Stoffell, Barry

2013-01-01

We determined the composition of ~30-m.y.-old solutions extracted from fluid inclusions in one of the world's largest and richest silver ore deposits at Fresnillo, Mexico. Silver concentrations average 14 ppm and have a maximum of 27 ppm. The highest silver, lead and zinc concentrations correlate with salinity, consistent with transport by chloro-complexes and confirming the importance of brines in ore formation. The temporal distribution of these fluids within the veins suggests mineralization occurred episodically when they were injected into a fracture system dominated by low salinity, metal-poor fluids. Mass balance shows that a modest volume of brine, most likely of magmatic origin, is sufficient to supply the metal found in large Mexican silver deposits. The results suggest that ancient epithermal ore-forming events may involve fluid packets not captured in modern geothermal sampling and that giant ore deposits can form rapidly from small volumes of metal-rich fluid. PMID:23792776

Purge-and-trap ion chromatography for the determination of trace ammonium ion in high-salinity water samples.

PubMed

Wang, Po-Yen; Wu, Jing-Yi; Chen, Hung-Jhen; Lin, Tzung-Yi; Wu, Chien-Hou

2008-04-25

It has always been assumed that purge-and-trap (P&T) method is only used for the analysis of volatile organic compounds (VOCs) in aqueous samples. In this paper, a novel P&T preconcentrator has been developed for the determination of trace amounts of ammonium ion in high-salinity water samples by ion chromatography (IC). Method performance is evaluated as a function of concentration of assistant purging material, purging time, and flow rate. Under the optimum P&T conditions with the purified nitrogen gas at flow rate 40 mL/min for 15.0 min at 40 degrees C, the overall collection efficiency is independent of the concentration of ammonium over the range 1.2-5.9 microM. The enrichment factor (EF) of ammonium correlates the ratio of the sample volume to the acceptor solution volume in the trap vessel, providing potentially unlimited increase of the ammonium signal. Our results indicate that environmental samples with low levels of ammonium in matrices with high concentrations of sodium can be easily analyzed and the detection limit down to 75 nM (1.35 ppb) level, corresponding to picomole of ammonia in the injected sample. Calibration graph was constructed with ammonium standards ranging from 0.05 to 6.0 microM and the linearity of the present method was good as suggested by the square of correlation coefficients being better than 0.997. Thus, we have demonstrated that the P&T-IC method allows the routine determination of ammonium ion in seawater samples without cation interferences.

Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

PubMed

Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

2017-04-14

An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg + ), ethylmercury (EtHg + ) and inorganic mercury (Hg 2+ ) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL -1 for EtHg + and 5-450ngL -1 for MeHg + and Hg 2+ . Limits of detection were 3.0ngL -1 for EtHg + and 1.5ngL -1 for MeHg + and Hg 2+ . Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

Transurethral ethanol injection therapy of benign prostatic hyperplasia: four-year follow-up.

PubMed

Sakr, Mostafa; Eid, Ahmed; Shoukry, Mohammed; Fayed, Abdelaziz

2009-02-01

Evaluating long-term (50 months) efficacy of transurethral intraprostatic injection of absolute ethanol to treat benign prostatic hyperplasia (BPH). A prospective study was conducted to evaluate 35 patients with BPH treated by transurethral injection of dehydrated ethanol. Mean age was 66.3 years. Endoscopic injection of 6-12 mL ethanol was carried out at 5-10 sites in the prostate. International Prostate Symptom Score (IPSS), maximum flow rate, prostate volume, postvoid residual and side effects or complications incidence were logged. Mean IPSS +/- standard deviation improved significantly from 22.0 +/- 3.89 preoperatively to 9.85 +/- 2.23 at 50 months follow-up. Mean peak urinary flow rate increased from 5.87 +/- 3.69 mL/s to 16.89 +/- 4.12 after 4 years. Mean residual urine volume had decreased from 68.6 +/- 49.98 mL to 36.02 +/- 20.87 after 4 years (P < 0.05). The prostate volume decreased from 52.67 +/- 20.43 g preoperatively to 49.94 +/- 21.28 g after 4 years (statistically significant). There were no intra-operative complications but post-operative urine retention occurred in all patients requiring catheterization for a mean 6.7 days. Acute epididymitis and chronic prostatitis occurred in two patients. Urethral stricture occurred in one patient. This technique appears to be safe and cost effective. No occurrence of retrograde ejaculation was detected. The long-term effects of ethanol injection of the prostate were satisfactory and acceptable as a minimally invasive therapeutic modality of selected patients.

Analysis of high gradient magnetic field effects on distribution of nanoparticles injected into pulsatile blood stream

NASA Astrophysics Data System (ADS)

Reza Habibi, Mohammad; Ghassemi, Majid; Hossien Hamedi, Mohammad

2012-04-01

Magnetic nanoparticles are widely used in a wide range of applications including data storage materials, pharmaceutical industries as magnetic separation tools, anti-cancer drug carriers and micro valve applications. The purpose of the current study is to investigate the effect of a non-uniform magnetic field on bio-fluid (blood) with magnetic nanoparticles. The effect of particles as well as mass fraction on flow field and volume concentration is investigated. The governing non-linear differential equations, concentration and Navier-stokes are coupled with the magnetic field. To solve these equations, a finite volume based code is developed and utilized. A real pulsatile velocity is utilized as inlet boundary condition. This velocity is extracted from an actual experimental data. Three percent nanoparticles volume concentration, as drug carrier, is steadily injected in an unsteady, pulsatile and non-Newtonian flow. A power law model is considered for the blood viscosity. The results show that during the systole section of the heartbeat when the blood velocity increases, the magnetic nanoparticles near the magnetic source are washed away. This is due to the sudden increase of the hydrodynamic force, which overcomes the magnetic force. The probability of vein blockage increases when the blood velocity reduces during the diastole time. As nanoparticles velocity injection decreases (longer injection time) the wall shear stress (especially near the injection area) decreases and the retention time of the magnetic nanoparticles in the blood flow increases.

Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection

DOE Data Explorer

Ebrahimi, Fatima [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)] (ORCID:0000000331095367); Raman, Roger [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)] (ORCID:0000000220273271)

2016-01-01

A large-volume flux closure during transient coaxial helicity injection (CHI) in NSTX-U is demonstrated through resistive magnetohydrodynamics (MHD) simulations. Several major improvements, including the improved positioning of the divertor poloidal field coils, are projected to improve the CHI start-up phase in NSTX-U. Simulations in the NSTX-U configuration with constant in time coil currents show that with strong flux shaping the injected open field lines (injector flux) rapidly reconnect and form large volume of closed flux surfaces. This is achieved by driving parallel current in the injector flux coil and oppositely directed currents in the flux shaping coils to form a narrow injector flux footprint and push the injector flux into the vessel. As the helicity and plasma are injected into the device, the oppositely directed field lines in the injector region are forced to reconnect through a local Sweet–Parker type reconnection, or to spontaneously reconnect when the elongated current sheet becomes MHD unstable to form plasmoids. In these simulations for the first time, it is found that the closed flux is over 70% of the initial injector flux used to initiate the discharge. These results could work well for the application of transient CHI in devices that employ super conducting coils to generate and sustain the plasma equilibrium.

Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection

DOE Data Explorer

Ebrahimi, F. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Raman, R. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

2016-04-01

A large-volume flux closure during transient coaxial helicity injection (CHI) in NSTX-U is demonstrated through resistive magnetohydrodynamics (MHD) simulations. Several major improvements, including the improved positioning of the divertor poloidal field coils, are projected to improve the CHI start-up phase in NSTX-U. Simulations in the NSTX-U configuration with constant in time coil currents show that with strong flux shaping the injected open field lines (injector flux) rapidly reconnect and form large volume of closed flux surfaces. This is achieved by driving parallel current in the injector flux coil and oppositely directed currents in the flux shaping coils to form a narrow injector flux footprint and push the injector flux into the vessel. As the helicity and plasma are injected into the device, the oppositely directed field lines in the injector region are forced to reconnect through a local Sweet–Parker type reconnection, or to spontaneously reconnect when the elongated current sheet becomes MHD unstable to form plasmoids. In these simulations for the first time, it is found that the closed flux is over 70% of the initial injector flux used to initiate the discharge. These results could work well for the application of transient CHI in devices that employ super conducting coils to generate and sustain the plasma equilibrium.

Quantification of Acetaminophen and Its Metabolites in Plasma Using UPLC-MS: Doors Open to Therapeutic Drug Monitoring in Special Patient Populations.

PubMed

Flint, Robert B; Mian, Paola; van der Nagel, Bart; Slijkhuis, Nuria; Koch, Birgit C P

2017-04-01

Acetaminophen (APAP, paracetamol) is the most commonly used drug for pain and fever in both the United States and Europe and is considered safe when used at registered dosages. Nevertheless, differences between specific populations lead to remarkable changes in exposure to potentially toxic metabolites. Furthermore, extended knowledge is required on metabolite formation after intoxication, to optimize antidote treatment. Therefore, the authors aimed to develop and validate a quick and easy analytical method for simultaneous quantification of APAP, APAP-glucuronide, APAP-sulfate, APAP-cysteine, APAP-glutathione, APAP-mercapturate, and protein-derived APAP-cysteine in human plasma by ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry. The internal standard was APAP-D4 for all analytes. Chromatographic separation was achieved with a reversed-phase Acquity ultraperformance liquid chromatography HSS T3 column with a runtime of only 4.5 minutes per injected sample. Gradient elution was performed with a mobile phase consisting of ammonium acetate, formic acid in Milli-Q ultrapure water or in methanol at flow rate of 0.4 mL/minute. A plasma volume of only 10 μL was required to achieve both adequate accuracy and precision. Calibration curves of all 6 analytes were linear. All analytes were stable for at least 48 hours in the autosampler; the high quality control of APAP-glutathione was stable for 24 hours. The method was validated according to the U.S. Food and Drug Administration guidelines. This method allows quantification of APAP and 6 metabolites, which serves purposes for research, as well as therapeutic drug monitoring. The advantage of this method is the combination of minimal injection volume, a short runtime, an easy sample preparation method, and the ability to quantify APAP and all 6 metabolites.

Multiresidue analysis of synthetic pyrethroid pesticides in grapes by gas chromatography with programmed temperature vaporizing-large volume injection coupled with ion trap mass spectrometry.

PubMed

Banerjee, Kaushik; Savant, Rahul H; Dasgupta, Soma; Patil, Sangram H; Oulkar, Dasharath P; Adsule, Pandurang G

2010-01-01

A multiresidue analysis method was optimized and validated for simultaneous estimation of 21 synthetic pyrethroid pesticides and their isomers in grape matrix at 10 ng/g and higher levels. The method involves extraction of a 10 g sample with 10 mL ethyl acetate, cleanup by dispersive SPE with primary-secondary amine (25 mg) sorbent, and estimation by GC/MS/MS large volume injection (LVI) through a programmed temperature vaporizer (PTV) injector. The PTV-LVI parameters of the gas chromatograph and the multiple reaction monitoring (MRM) parameters of the ion trap mass spectrometer were optimized for each compound to achieve the highest SIN. For each analyte, the unique and most abundant MRM transition was used for quantification, along with the next most abundant MRM transition for confirmatory identification. The abundance ratio of the confirmatory to quantifier MRMs was used to ensure unambiguous residue monitoring in unknown samples within a 20% tolerance range at the 10 ng/g level. The analytes were separated on a TR-5MS capillary column within a 22 min run time. The method was selective and sensitive and ensured separation of the synthetic pyrethroids from high-boiling matrix components. The LOD and LOQ of the analytes ranged between 0.5 to 3.1 and 2.5 to 10 ng/g, respectively. Linearity of solvent and matrix-matched calibrations between 2.0 and 250 ng/g was established for each compound with r2 > 0.99. Recovery at 10, 25, and 50 ng/g levels of fortification in grapes ranged within 77-115% with associated RSD values (n = 8) up to 20%.

Volume of a laser-induced microjet

NASA Astrophysics Data System (ADS)

Kawamoto, Sennosuke; Hayasaka, Keisuke; Noguchi, Yuto; Tagawa, Yoshiyuki

2015-11-01

Needle-free injection systems are of great importance for medical treatments. In spite of their great potential, these systems are not commonly used. One of the common problems is strong pain caused by diffusion shape of the jet. To solve this problem, the usage of a high-speed highly-focused microjet as needle-free injection system is expected. It is thus crucial to control important indicators such as ejected volume of the jet for its safe application. We conduct experiments to reveal which parameter influences mostly the ejected volume. In the experiments, we use a glass tube of an inner diameter of 500 micro-meter, which is filled with the liquid. One end is connected to a syringe and the other end is opened. Radiating the pulse laser instantaneously vapors the liquid, followed by the generation of a shockwave. We find that the maximum volume of a laser-induced bubble is approximately proportional to the ejected volume. It is also found that the occurrence of cavitation does not affect the ejected volume while it changes the jet velocity.

Direct large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry determination of artificial sweeteners sucralose and acesulfame in well water.

PubMed

Wu, Minghuo; Qian, Yichao; Boyd, Jessica M; Hrudey, Steve E; Le, X Chris; Li, Xing-Fang

2014-09-12

Acesulfame (ACE) and sucralose (SUC) have become recognized as ideal domestic wastewater contamination indicators. Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis is commonly used; however, the sensitivity of SUC is more than two orders of magnitude lower than that of ACE, limiting the routine monitoring of SUC. To address this issue, we examined the ESI behavior of both ACE and SUC under various conditions. ACE is ionic in aqueous solution and efficiently produces simple [M-H](-) ions, but SUC produces multiple adduct ions, limiting its sensitivity. The formic acid (FA) adducts of SUC [M+HCOO](-) are sensitively and reproducibly generated under the LC-MS conditions. When [M+HCOO](-) is used as the precursor ion for SUC detection, the sensitivity increases approximately 20-fold compared to when [M-H](-) is the precursor ion. To further improve the limit of detection (LOD), we integrated the large volume injection approach (500μL injection) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which reduced the method detection limit (MDL) to 0.2ng/L for ACE and 5ng/L for SUC. To demonstrate the applicability of this method, we analyzed 100 well water samples collected in Alberta. ACE was detected in 24 wells at concentrations of 1-1534ng/L and SUC in 8 wells at concentrations of 65-541ng/L. These results suggest that wastewater is the most likely source of ACE and SUC impacts in these wells, suggesting the need for monitoring the quality of domestic well water. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of sildenafil citrate (Viagra®) on trace element concentration in serum and brain of rats.

PubMed

Fayed, Abdel-Hasseb A; Gad, Shereen B

2011-12-01

As a vasodilator with good hemodynamic effects, sildenafil has been successfully used in the treatment of patients with pulmonary hypertension and cardiovascular diseases. By selectively inhibiting phosphodiestrase type 5 (PDE-5) and thus effectively reducing the breakdown of c GMP, sildenafil administration can markedly improve the erectile dysfunction. Sildenafil also elevates localized cerebral blood flow in rat brain. The objective of the present study was to investigate the effect of sildenafil on the level of trace elements (Zinc (Zn), copper (Cu), iron (Fe), selenium (Se), cobalt (Co), and chromium (Cr)) in blood and brain of rats. Sixteen male albino rats weighing 180-200 g were divided into two groups (8 rats/group). Sildenafil (Viagra, Pfizer Inc.) was dissolved in saline and administered at a dose of 10mg/kg i.p. (0.5 ml volume) to rats in the treated group every 72 h for 12 injections. Rats in the control group were administered the same volume of saline as in treated group. All rats were sacrificed 24h after the last injection. Blood samples were collected and serum was separated and stored at -20°C. Brains were dissected and stored frozen until analysis. Trace elements concentrations were determined by flame emission atomic absorption spectrophotometer. Results showed that sildenafil injection significantly (P<0.05) increased serum and brain Se and Cu concentrations. Moreover, sildenafil increased the Cr concentration in the brain tissue. It was concluded that sildenafil citrate administration increased serum Se and Cu as well as, increased brain Se, Cu, and Cr concentrations in rats. Copyright © 2011 Elsevier GmbH. All rights reserved.

New approach to the fast screening of plant oil samples for F-, Cl-, Br- and S-organic compounds on the trace level.

PubMed

Chivarzin, M E; Revelsky, I A; Nikoshina, A V; Buldyzkova, A N; Chepeliansky, D A; Revelsky, A I; Buriak, A K

2016-04-01

The fast method of the simultaneous determination of F(-), Cl(-), Br(-) and SO4(2-) anions in the deionized water on the trace level by ion chromatography using thorough cleaning of respective water containers, 10 μM NaHCO3 water solution as eluent, short Metrohm (50 × 4 mm) separation column and a large water volume injection is proposed. Calculated detection limits are 10(-9)-10(-8)% depending on the element. The method for the fast screening of plant oil samples for the total fluorine-, chlorine-, bromine- and sulfur-organic compounds content (calculated for the respective elements) on the trace level is developed. It is based on the high temperature combustion of oil sample in oxygen flow, absorption of the conversion products in deionized water and whole absorbate volume analysis for F(-), Cl(-), Br(-) and SO4(2-) anions, corresponding to the respective elements, using the developed method of these anions analysis by ion chromatography. The samples of soya, olive, sunflower and cotton seed oil were analyzed. The method detection limits (for 1mg sample) were 2 × 10(-6)%, 2 × 10(-6)%, 5 × 10(-6)% and 5 × 10(-6)% for fluorine, chlorine, bromine and sulfur, respectively. The relative standard deviation was ≤ 15%. The method gives the compressed information about the total content of all target and nontarget fluorine-, chlorine-, bromine- and sulfur-organic compounds in plant oils. Copyright © 2015. Published by Elsevier B.V.

Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.

2006-11-30

This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understandingmore » of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.« less

Evaluation of an ODS column modified with zwitterionic/nonionic mixed surfactants and its application to direct injection determination of inorganic anions.

PubMed

Hasegawa, Takuya; Umemura, Tomonari; Koide, Akira; Chiba, Koichi; Ueki, Yuji; Tsunoda, Kin-ichi; Haraguchi, Hiroki

2005-08-01

An octadecylsilica (ODS) column modified with zwitterionic/nonionic mixed surfactants was evaluated for the direct injection determination of inorganic anions in biological fluids by ion chromatography. A zwitterionic surfactant (sulfobetaine-type) and a nonionic surfactant (polyoxyethylene-type) were used for a stationary-phase modification. When aqueous electrolyte solutions with concentrations of sub-mM to several mM were used as a mobile phase, the zwitterionic surfactant coated on the ODS surface exhibited unique separation selectivity for ionic species, while the nonionic surfactant coated on the ODS might have formed a hydrophilic network over the ODS surface and restricted matrix proteins from adsorbing on the stationary phase. Consequently, the mixed surfactant-modified column system allowed an efficient ion chromatographic separation of inorganic anions as well as a size-exclusive removal of column-fouling proteins. This separation system was applied to the direct injection determination of UV-absorbing anions in human saliva. The detection limits for nitrite, nitrate, iodide and thiocyanate were 3.1, 2.7, 4.5 and 25 microM, respectively, with UV detection at 210 nm (injection volume; 20 microl), and their relative standard deviations for 5 replicate measurements of saliva samples spiked with 100 microM each of those anions were 1.4, 0.9, 2.2 and 5.5%, respectively.

Matrix-enhanced degradation of p,p'-DDT during gas chromatographic analysis: A consideration

USGS Publications Warehouse

Foreman, W.T.; Gates, Paul M.

1997-01-01

Analysis of p,p‘-DDT in environmental samples requires monitoring the GC-derived breakdown of this insecticide, which produces p,p‘-DDD and/or p,p‘-DDE, both also primary environmental degradation products. A performance evaluation standard (PES) containing p,p‘-DDT but notp,p‘-DDD or p,p‘-DDE can be injected at regular intervals throughout an analytical sequence to monitor GC degradation. Some U.S. EPA methods limit GC breakdown of DDT in the PES to ≤20%. GC/MS analysis of large-volume natural water samples fortified with deuterium- and 13C-labeled p,p‘-DDT exhibited up to 65% DDT breakdown by the GC inlet. These matrix-enhanced GC degradation amounts substantially exceeded the <20% breakdown levels indicated by bracketing injections of the PES containing unlabeled and labeled DDT. Substantial matrix-enhanced GC degradation was not observed during analysis of a limited number of fractionated bed-sediment extracts containing labeled DDT. Use of isotopically labeled DDT seems to provide an effective tool for monitoring sample-specific DDT breakdown during GC/MS analysis. However, analyte co-elutions render impractical their use in GC/ECD analysis. The oc currence of matrix-enhanced GC degradation might have important implications on data quality and the resultant interpretations of the environmental degradation of DDT and other thermolabile contaminants.

Extension of a dynamic headspace multi-volatile method to milliliter injection volumes with full sample evaporation: Application to green tea.

PubMed

Ochiai, Nobuo; Sasamoto, Kikuo; Tsunokawa, Jun; Hoffmann, Andreas; Okanoya, Kazunori; MacNamara, Kevin

2015-11-20

An extension of multi-volatile method (MVM) technology using the combination of a standard dynamic headspace (DHS) configuration, and a modified DHS configuration incorporating an additional vacuum module, was developed for milliliter injection volume of aqueous sample with full sample evaporation. A prior step involved investigation of water management by weighing of the water residue in the adsorbent trap. The extended MVM for 1 mL aqueous sample consists of five different DHS method parameter sets including choice of the replaceable adsorbent trap. An initial two DHS sampling sets at 25°C with the standard DHS configuration using a carbon-based adsorbent trap target very volatile solutes with high vapor pressure (>10 kPa) and volatile solutes with moderate vapor pressure (1-10 kPa). Subsequent three DHS sampling sets at 80°C with the modified DHS configuration using a Tenax TA trap target solutes with low vapor pressure (<1 kPa) and/or hydrophilic characteristics. After the five sequential DHS samplings using the same HS vial, the five traps are sequentially desorbed with thermal desorption in reverse order of the DHS sampling and the desorbed compounds are trapped and concentrated in a programmed temperature vaporizing (PTV) inlet and subsequently analyzed in a single GC-MS run. Recoveries of 21 test aroma compounds in 1 mL water for each separate DHS sampling and the combined MVM procedure were evaluated as a function of vapor pressure in the range of 0.000088-120 kPa. The MVM procedure provided high recoveries (>88%) for 17 test aroma compounds and moderate recoveries (44-71%) for 4 test compounds. The method showed good linearity (r(2)>0.9913) and high sensitivity (limit of detection: 0.1-0.5 ng mL(-1)) even with MS scan mode. The improved sensitivity of the method was demonstrated with analysis of a wide variety of aroma compounds in brewed green tea. Compared to the original 100 μL MVM procedure, this extension to 1 mL MVM allowed detection of nearly twice the number of aroma compounds, including 18 potent aroma compounds from top-note to base-note (e.g. 2,3-butanedione, coumarin, furaneol, guaiacol, cis-3-hexenol, linalool, maltol, methional, 3-methyl butanal, 2,3,5-trimethyl pyrazine, and vanillin). Sensitivity for 23 compounds improved by a factor of 3.4-15 under 1 mL MVM conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry.

PubMed

Sigrist, Mirna; Albertengo, Antonela; Beldoménico, Horacio; Tudino, Mabel

2011-04-15

A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH(3) generation using 3.5 mol L(-1) HCl as carrier solution and 0.35% (m/v) NaBH(4) in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl(-), SO(4)(2-), NO(3)(-), HPO(4)(2-), HCO(3)(-) on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C(6)H(8)O(6) solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 μg L(-1) and 0.6 μg L(-1) for As(III) and inorganic total As, respectively, were obtained for a 500 μL sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samplesh(-1). The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species separation was performed through the employ of a serial connection of membrane filters and anion-exchange cartridges. Advantages derived from this approach were evaluated. HPLC-ICPMS was employed to study the consistency of the analytical results. Copyright © 2011 Elsevier B.V. All rights reserved.

The provision of non-needle/syringe drug injecting paraphernalia in the primary prevention of HCV among IDU: a systematic review.

PubMed

Gillies, Michelle; Palmateer, Norah; Hutchinson, Sharon; Ahmed, Syed; Taylor, Avril; Goldberg, David

2010-11-23

Sharing drug injecting paraphernalia other than needles and syringes (N/S) has been implicated in the transmission of Hepatitis C virus (HCV) among injecting drug users (IDU). We aimed to determine whether the provision of sterile non-N/S injecting paraphernalia reduces injecting risk behaviours or HCV transmission among IDU. A systematic search of seven databases and the grey literature for articles published January 1989-February 2010 was undertaken. Thirteen studies (twelve observational and one non-randomized uncontrolled pilot intervention) were identified and appraised for study design and quality by two investigators. No studies examined the association between the provision of non-N/S injecting paraphernalia and incident HCV infection. One cross-sectional study found that individuals who frequently, compared to those who infrequently, used sterile cookers and water, were less likely to report prevalent HCV infection. Another found no association between the uptake of sterile non-N/S injecting paraphernalia and self-reported sharing of this paraphernalia. The remaining observational studies used attendance at needle and syringe exchange programmes (NSP) or safer injection facilities (SIF) that provided non-N/S injecting paraphernalia as a proxy measure. Eight studies presented adjusted odds ratios, ranging from 0.3 to 0.9, suggesting a reduced likelihood of self-reported sharing of non-N/S injecting paraphernalia associated with use of NSP or SIF. There was substantial uncertainty associated with these estimates however. Three unadjusted studies reported a reduction in the prevalence of sharing of non-N/S injecting paraphernalia over time among NSP users. Only one study reported an adjusted temporal trend in the prevalence of sharing non-N/S injecting paraphernalia, finding higher rates among non-NSP users than NSP users at each time point, and a greater reduction in sharing among non-NSP than NSP users over time. Study limitations included the use of convenience samples, self-reported exposure and outcome measures, flawed classification of the exposed and unexposed groups, and inadequate adjustment for potential confounding variables. The evidence to demonstrate that the provision of sterile non-N/S injecting paraphernalia reduces HCV transmission or modifies injecting risk behaviours is currently limited by an insufficient volume and quality of studies. Further research is required to inform practice and policy in this area.

Quantitative analysis of 23-hydroxybetulinic acid in mouse plasma using electrospray liquid chromatography/mass spectrometry.

PubMed

Yang, Min; Wang, Guang Ji; Wang, Su Jun; Li, Xiao Tian; Xu, Yu Ping; Wang, Song Pei; Xiang, Jing De; Pan, Shang Ren; Cao, Guo Xian; Ye, Wen Cai

2005-01-01

23-Hydroxybetulinic acid is a newly isolated derivative of betulinic acid. The agent exhibits potential anti-tumor activity and functions in this regard via apoptosis. In support of pharmacokinetic and toxicological evaluations, a new assay based on liquid chromatography/mass spectrometry (LC/MS) was developed for the quantitative analysis of 23-hydroxybetulinic acid. Sample preparation consisted of extraction of the plasma by the addition of methylene chloride followed by centrifugation. Aliquots of the supernatant were analyzed using an isocratic reversed-phase high-performance liquid chromatography (HPLC) system coupled to a negative ion electrospray mass spectrometer. Molecules of 23-hydroxybetulinic acid and the internal standard limonin were detected using selected ion monitoring at m/z 471 and 469, respectively. The limit of detection of 23-hydroxybetulinic acid was 0.05 pg (0.11 fmol) injected on-column (10 pg/mL, 5 microL injection volume), and the limit of quantitation was 10 pg (21.19 fmol, 2 ng/mL, 5 muL injection volume). 23-Hydroxybetulinic acid was stable in plasma samples at -20 degrees C for at least 3 weeks. The intra-day and inter-day coefficients of variation of the assay were 3.0 and 4.8%, respectively. The utility of the assay was demonstrated by measuring 23-hydroxybetulinicacid in mouse plasma following intragastric administration (IG) in vivo. Pharmacokinetic parameters were calculated using the 3P97 pharmacokinetic software package. A two-compartment, first-order model was selected for pharmacokinetic modeling. The result showed that after IG of 200 mg/kg 23-hydroxybetulinic acid, the plasma concentrations reached peaks at 2 h with C(max) of 3.1 microg/mL. The 200 mg/kg 23-hydroxybetulinic acid suspension IG doses were found to have long elimination half-lives of 25.6 h and low bioavailability of 2.3%. No interference was noted due to endogenous substances. These analytical methods should be of value in future studies related to the development and characterization of 23-hydroxybetulinic acid. Copyright 2005 John Wiley & Sons, Ltd.

Temporal lobe volume predicts Wada memory test performance in patients with mesial temporal sclerosis.

PubMed

Ding, Kan; Gong, Yunhua; Modur, Pradeep N; Diaz-Arrastia, Ramon; Agostini, Mark; Gupta, Puneet; McColl, Roderick; Hays, Ryan; Van Ness, Paul

2016-02-01

The Wada test is widely used in the presurgical evaluation of potential temporal lobectomy patients to predict postoperative memory function. Expected asymmetry (EA), defined as Wada memory lateralized to the nonsurgical hemisphere, or a higher score after injection of the surgical hemisphere would be considered favorable in terms of postoperative memory outcome. However, in some cases, nonlateralized memory (NM) results, with no appreciable asymmetry, may occur because of impaired scores after both injections, often leading to denial of surgery. The reason for such nonlateralized Wada memory in patients with intractable temporal lobe epilepsy (TLE) remains unclear. Given that quantitative morphometric magnetic resonance imaging studies in TLE patients have shown bilateral regional atrophy in temporal and extratemporal structures, we hypothesized that the volume loss in contralateral temporal structures could contribute to nonlateralized Wada memory performance. To investigate this, we examined the relationship between the volume changes of temporal structures and Wada memory scores in patients with intractable TLE with mesial temporal sclerosis (MTS) using an age- and gender-matched control group. Memory was considered nonlateralized if the absolute difference in the total correct recall scores between ipsilateral and contralateral injections was <11%. Among 21 patients, Wada memory was lateralized in 15 and nonlateralized in 6 patients, with all the nonlateralized scores being observed in left TLE. The recall scores after ipsilateral injection were significantly lower in patients with an NM profile than an EA profile (23 ± 14% vs. 59 ± 18% correct recall, p ≤ 0.001). However, the recall scores after contralateral injection were low but similar between the two groups (25 ± 17% vs. 25 ± 15% correct recall, p=0.97). Compared to controls, all the patients showed greater volume loss in the temporal regions. However, patients with a NM profile showed significantly more volume loss than those with a lateralized memory profile in both contralateral and ipsilateral temporal regions (p<0.05). Left hemispheric Wada memory performance correlated positively with the size of the left mesial and neocortical temporal structures (r=0.49-0.63, p=0.005-0.04). Our study suggests that volume loss in the nonsurgical temporal structures is associated with nonlateralized Wada memory results in patients with intractable TLE. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly selective micro-sequential injection lab-on-valve (muSI-LOV) method for the determination of ultra-trace concentrations of nickel in saline matrices using detection by electrothermal atomic absorption spectrometry.

PubMed

Long, Xiangbao; Miró, Manuel; Jensen, Rikard; Hansen, Elo Harald

2006-10-01

A highly selective procedure is proposed for the determination of ultra-trace level concentrations of nickel in saline aqueous matrices exploiting a micro-sequential injection Lab-On-Valve (muSI-LOV) sample pretreatment protocol comprising bead injection separation/pre-concentration and detection by electrothermal atomic absorption spectrometry (ETAAS). Based on the dimethylglyoxime (DMG) reaction used for nickel analysis, the sample, as contained in a pH 9.0 buffer, is, after on-line merging with the chelating reagent, transported to a reaction coil attached to one of the external ports of the LOV to assure sufficient reaction time for the formation of Ni(DMG)(2) chelate. The non-ionic coordination compound is then collected in a renewable micro-column packed with a reversed-phase copolymeric sorbent [namely, poly(divinylbenzene-co-N-vinylpyrrolidone)] containing a balanced ratio of hydrophilic and lipophilic monomers. Following elution by a 50-muL methanol plug in an air-segmented modality, the nickel is finally quantified by ETAAS. Under the optimized conditions and for a sample volume of 1.8 mL, a retention efficiency of 70 % and an enrichment factor of 25 were obtained. The proposed methodology showed a high tolerance to the commonly encountered alkaline earth matrix elements in environmental waters, that is, calcium and magnesium, and was successfully applied for the determination of nickel in an NIST standard reference material (NIST 1640-Trace elements in natural water), household tap water of high hardness and local seawater. Satisfying recoveries were achieved for all spiked environmental water samples with maximum deviations of 6 %. The experimental results for the standard reference material were not statistically different to the certified value at a significance level of 0.05.

[Investigation of Coxiella burnetii contamination in commercial milk and PCR method for the detection of C. burnetii in egg].

PubMed

Hirai, Akihiko; Kaneko, Seiji; Nakama, Akiko; Ishizaki, Naoto; Odagiri, Megumi; Kai, Akemi; Sadamasu, Kenji; Shinkai, Takayuki; Yano, Kazuyoshi; Morozumi, Satoshi

2005-06-01

A total of 244 milk samples collected from supermarkets in Tokyo were examined for contamination with Coxiella burnetii. C. burnetii DNA was detected in 131 (53.7%) of the samples by nested PCR. PCR-positive samples were injected into immunosuppressed A/J strain mice. Of the 22 PCR-positive milk samples tested, none resulted in isolation of C. burnetii from the mice. Heat-treatment was sufficient to inactivate C. burnetii in commercial milk. In addition, a PCR detection method for C. burnetii in chicken egg was developed. Egg yolk was added to an equal volume of 1 mol/L of NaCl phosphate buffer and homogenized for removal of protein and lipid. After centrifugal separation, the supernatant was removed, and template DNA in the precipitate was extracted using SDS, proteinase K and NaI. Using such prepared samples, 3.2 x 10(1) C. burnetii particles in 1 g of egg yolk could be detected by nested PCR. All of 200 chicken egg samples collected from supermarkets in Tokyo were negative for C. burnetii by the nested PCR method.

Resolving the detailed structure of cortical and thalamic neurons in the adult rat brain with refined biotinylated dextran amine labeling.

PubMed

Ling, Changying; Hendrickson, Michael L; Kalil, Ronald E

2012-01-01

Biotinylated dextran amine (BDA) has been used frequently for both anterograde and retrograde pathway tracing in the central nervous system. Typically, BDA labels axons and cell somas in sufficient detail to identify their topographical location accurately. However, BDA labeling often has proved to be inadequate to resolve the fine structural details of axon arbors or the dendrites of neurons at a distance from the site of BDA injection. To overcome this limitation, we varied several experimental parameters associated with the BDA labeling of neurons in the adult rat brain in order to improve the sensitivity of the method. Specifically, we compared the effect on labeling sensitivity of: (a) using 3,000 or 10,000 MW BDA; (b) injecting different volumes of BDA; (c) co-injecting BDA with NMDA; and (d) employing various post-injection survival times. Following the extracellular injection of BDA into the visual cortex, labeled cells and axons were observed in both cortical and thalamic areas of all animals studied. However, the detailed morphology of axon arbors and distal dendrites was evident only under optimal conditions for BDA labeling that take into account the: molecular weight of the BDA used, concentration and volume of BDA injected, post-injection survival time, and toning of the resolved BDA with gold and silver. In these instances, anterogradely labeled axons and retrogradely labeled dendrites were resolved in fine detail, approximating that which can be achieved with intracellularly injected compounds such as biocytin or fluorescent dyes.

Effects of injection pressure variation on mixing in a cold supersonic combustor with kerosene fuel

NASA Astrophysics Data System (ADS)

Liu, Wei-Lai; Zhu, Lin; Qi, Yin-Yin; Ge, Jia-Ru; Luo, Feng; Zou, Hao-Ran; Wei, Min; Jen, Tien-Chien

2017-10-01

Spray jet in cold kerosene-fueled supersonic flow has been characterized under different injection pressures to assess the effects of the pressure variation on the mixing between incident shock wave and transverse cavity injection. Based on the real scramjet combustor, a detailed computational fluid dynamics model is developed. The injection pressures are specified as 0.5, 1.0, 2.0, 3.0 and 4.0 MPa, respectively, with the other constant operation parameters (such as the injection diameter, angle and velocity). A three dimensional Couple Level Set & Volume of Fluids approach incorporating an improved Kelvin-Helmholtz & Rayleigh-Taylor model is used to investigate the interaction between kerosene and supersonic air. The numerical simulations primarily concentrate on penetration depth, span expansion area, angle of shock wave and sauter mean diameter distribution of the kerosene droplets with/without evaporation. Validation has been implemented by comparing the calculated against the measured in literature with good qualitative agreement. Results show that the penetration depth, span-wise angle and expansion area of the transverse cavity jet are all increased with the injection pressure. However, when the injection pressure is further increased, the value in either penetration depth or expansion area increases appreciably. This study demonstrates the feasibility and effectiveness of the combination of Couple Level Set & Volume of Fluids approach and an improved Kelvin-Helmholtz & Rayleigh-Taylor model, in turn providing insights into scramjet design improvement.

Sensitivity of the Saline Load Test for Traumatic Arthrotomy of the Ankle With Ankle Arthroscopy Simulation.

PubMed

Bohl, Daniel D; Frank, Rachel M; Lee, Simon; Hamid, Kamran S; Holmes, George B; Lin, Johnny; Lee, Simon

2018-06-01

The saline load test has been used to evaluate for traumatic arthrotomy in orthopedics. The purpose of this study was to determine the volume of saline required to detect traumatic arthrotomy of the ankle. Forty-two patients undergoing elective ankle arthroscopy were prospectively enrolled. For each patient, a standard 4-mm anteromedial portal was established. Next, an 18-gauge needle was inserted at the site of the anterolateral portal. Sterile saline was slowly injected through the needle until saline extravasated from the anteromedial portal. Saline volumes at the time of extravasation were recorded and analyzed. The saline volume required to achieve extravasation ranged from 0.2 to 60.0 mL. The median saline volume required to achieve extravasation was 9.7 mL (interquartile range, 3.8-29.6 mL); however, 5 of 42 patients required volumes between 50.0 and 60.0 mL. A total of 50.0 mL was required to achieve 90% sensitivity, 55.0 mL to achieve 95% sensitivity, and 60.0 mL to achieve 99% sensitivity. The previously recommended 30 mL of saline required to reliably detect traumatic arthrotomy of the ankle may be too small a volume. The present study suggests that clinicians should attempt to inject 60 mL of saline to effectively rule out a traumatic arthrotomy injury. Because of the study's methods involving an anteromedial arthrotomy with anterolateral saline injection, these findings may be most valid for arthrotomies on the medial side of the ankle.

The real estate of myoblast cardiac transplantation: negative remodeling is associated with location.

PubMed

McCue, Jonathan D; Swingen, Cory; Feldberg, Tanya; Caron, Gabe; Kolb, Adam; Denucci, Christopher; Prabhu, Somnath; Motilall, Randy; Breviu, Brian; Taylor, Doris A

2008-01-01

Skeletal myoblast transplantation has been proposed as a therapy for ischemic cardiomyopathy owing to its possible role in myogenesis. The relative safety and efficacy based on location within scar is not known. We hypothesized that skeletal myoblasts transplanted into peripheral scar (compared with central scar) would more effectively attenuate negative left ventricular (LV) remodeling but at the risk of arrhythmia. New Zealand White rabbits (n = 34) underwent mid-left anterior descending artery (LAD) ligation to produce a transmural LV infarction. One month after LAD ligation, skeletal myoblasts were injected either in the scar center (n = 13) or scar periphery (n = 10) and compared with saline injection (n = 11). Holter monitoring and magnetic resonance imaging (MRI) was performed pre-injection; Holter monitoring was continued until 2 weeks after injection, with follow-up MRI at 1 month. The centrally treated animals demonstrated increased LV end-systolic volume, end-diastolic volume, and mass that correlated with the number of injected cells. There was a trend toward attenuation of negative LV remodeling in peripherally treated animals compared with vehicle. Significant late ectopy was seen in several centrally injected animals, with no late ectopy seen in peripherally injected animals. We noted untoward effects with respect to negative LV remodeling after central injection, suggesting that transplanted cell location with respect to scar may be a key factor in the safety and efficacy of skeletal myoblast cardiac transplantation. Administration of skeletal myoblasts into peripheral scar appears safe, with a trend toward improved function in comparison with sham injection.

Correlation between colonic secretion and colonic motility in rats: Role of ghrelin

PubMed Central

Huang, Hsien-Hao; Ting, Ching-Heng; Syu, Yu-Fong; Chang, Shi-Chuan; Chen, Chih-Yen

2016-01-01

AIM To explore the relationship between colonic secretory function and colonic motility. METHODS Using a rat model chronically implanted with intracerebroventricular (ICV) and cecal catheters, we validated the correlation between colonic secretion and colonic motor functions, as well as the role of ICV injection volume. RESULTS Compared to saline controls (5 μL/rat), ICV acyl ghrelin at 1 nmol/5 μL enhanced the total fecal weight, accelerated the colonic transit time, and increased the fecal pellet output during the first hour post-injection, while ICV des-acyl ghrelin at 1 nmol/5 μL only accelerated the colonic transit time. These stimulatory effects on colonic motility and/or secretion from acyl ghrelin and des-acyl ghrelin disappeared when the ICV injection volume increased to 10 μL compared with saline controls (10 μL/rat). Additionally, the ICV injection of 10 μL of saline significantly shortened the colonic transit time compared with the ICV injection of 5 μL of saline. The total fecal weight during the first hour post-injection correlated with the colonic transit time and fecal pellet output after the ICV injection of acyl ghrelin (1 nmol/5 μL), whereas the total fecal weight during the first hour post-injection correlated with the fecal pellet output but not the colonic transit time after the ICV injection of des-acyl ghrelin (1 nmol/5 μL). CONCLUSION Colonic secretion does not always correlate with colonic motility in response to different colonic stimulations. Acyl ghrelin stimulates colonic secretion. PMID:28028362

Capillary Imbibition of Hydraulic Fracturing Fluids into Partially Saturated Shale

NASA Astrophysics Data System (ADS)

Birdsell, D.; Rajaram, H.; Lackey, G.

2015-12-01

Understanding the migration of hydraulic fracturing fluids injected into unconventional reservoirs is important to assess the risk of aquifer contamination and to optimize oil and gas production. Capillary imbibition causes fracturing fluids to flow from fractures into the rock matrix where the fluids are sequestered for geologically long periods of time. Imbibition could explain the low amount of flowback water observed in the field (5-50% of the injected volume) and reduce the chance of fracturing fluid migrating out of formation towards overlying aquifers. We present calculations of spontaneous capillary imbibition in the form of an "imbibition rate parameter" (A) based on the only known exact analytical solution for spontaneous capillary imbibition. A depends on the hydraulic and capillary properties of the reservoir rock, the initial water saturation, and the viscosities of the wetting and nonwetting fluids. Imbibed volumes can be large for a high permeability shale gas reservoir (up to 95% of the injected volume) or quite small for a low permeability shale oil reservoir (as low as 3% of the injected volume). We also present a nondimensionalization of the imbibition rate parameter, which facilitates the calculation of A and clarifies the relation of A to initial saturation, porous medium properties, and fluid properties. Over the range of initial water saturations reported for the Marcellus shale (0.05-0.6), A varies by less than factors of ~1.8 and ~3.4 for gas and oil nonwetting phases respectively. However, A decreases significantly for larger initial water saturations. A is most sensitive to the intrinsic permeability of the reservoir rock and the viscosity of the fluids.

INTRAOPERATIVE FAT GRAFTING INTO THE PECTORALIS AND LATISSIMUS DORSI MUSCLES-NOVEL MODIFICATION OF AUTOLOGOUS BREAST RECONSTRUCTION WITH EXTENDED LATISSIMUS DORSI FLAP.

PubMed

Streit, L; Dražan, L; Schneiderová, M; Kubek, T; Sin, P; Veselý, K; Coufal, O; Veselý, J

2017-01-01

The latissimus dorsi flap is a reliable and one of the most commonly used methods of both immediate and delayed breast reconstruction. Its disadvantage is the limited volume of transferred tissue. The authors present their experience with the use of extended latissimus dorsi flap associated with immediate fat grafting into the pectoralis and latissimus dorsi muscles for secondary breast reconstruction. From 2013 to 2016, 14 patients underwent secondary unilateral total breast reconstruction with extended latissimus dorsi flap associated with primary fat grafting into the pectoralis major and latissimus dorsi muscles. Fat was injected under visual control between muscle fibers. Fat injected into the pectoralis muscle formed an apparent bulging - autoprosthesis. Mean patient age was 48.2 years (range, 34 to 64 years). Mean injected fat volume was 86.4 ml (range, 50 to 160 ml) and majority of this volume was injected into the pectoralis muscle. All flaps healed uneventfully and no fat grafting-related complications were observed. The most common complication was donor site seroma, which occurred in 57.1%. Results of postoperative ultrasound examination were evaluated. Incidence and the size of oil cysts and fat necroses were significantly lower in muscular layer in comparison with the subcutaneous layer of the reconstructed breast. Immediate fat transfer into the pectoralis and latissimus dorsi muscle increases the breast volume during the reconstruction with extended latissimus dorsi flap avoiding implant-related complications when abdominal tissue is not available. Pectoralis and latissimus dorsi muscles were shown as reliable and safe recipients for fat grafting.

Subsurface injection of treated sewage into a saline-water aquifer at St. Petersburg, Florida - Water-quality changes and potential for recovery of injected sewage

USGS Publications Warehouse

Hickey, J.J.; Ehrlich, G.G.

1984-01-01

The city of St. Petersburg is testing subsurface injection of treated sewage into the Floridan aquifer as a means of eliminating discharge of sewage to surface waters and as a means of storing treated sewage for future nonpotable reuse. The injection zone at the test site at the start of injection contained saline water with chloride concentrations ranging from 14,000 to 20,000 milligrams per liter (mg/l). Treated sewage with a mean chloride concentration of 170 mg/ml was injected through a single well for 12 months at a mean rate of 4.7 x 105 cubic feet per day. The volume of water injected during the year was 1.7x108 cubic feet. Dissolved oxygen was contained in the sewage prior to injection. Water removed from the injection zone during injection was essentially free of oxygen. Probable growth of denitrifying bacteria and, thus, microbial denitrification, was suggested by bacterial counts in water from two observation wells that were close to the injection well. The volume fraction of treated sewage in water from wells located 35 feet and 733 feet from the injection well and open to the upper part of the injection zone stabilized at about 0.9 and 0.75, respectively. Chloride concentrations stabilized at about 1,900 mg/l in water from the well that was 35 feet from the injection well and stabilized at about 4,000 mg/l in water from the well that was 733 feet from the injection well. These and other data suggest that very little near injection-quality treated sewage would be recoverable from storage in the injection zone.The city of St. Petersburg is testing subsurface injection of treated sewage into the Floridan aquifer as a means of eliminating discharge of sewage to surface waters and as a means of storing treated sewage for future nonpotable reuse. The injection zone at the test site at the start of injection contained saline water with chloride concentrations ranging from 14,000 to 20,000 milligrams per liter (mg/l). Data suggest that very little near injection-quality treated sewage would be recoverable from storage in the injection zone.

Intra-Arterial Delivery of AAV Vectors to the Mouse Brain After Mannitol Mediated Blood Brain Barrier Disruption

PubMed Central

Santillan, Alejandro; Sondhi, Dolan; Dyke, Jonathan P.; Crystal, Ronald G.; Gobin, Y. Pierre; Ballon, Douglas J.

2014-01-01

The delivery of therapeutics to neural tissue is greatly hindered by the blood brain barrier (BBB). Direct local delivery via diffusive release from degradable implants or direct intra-cerebral injection can bypass the BBB and obtain high concentrations of the therapeutic in the targeted tissue, however the total volume of tissue that can be treated using these techniques is limited. One treatment modality that can potentially access large volumes of neural tissue in a single treatment is intra-arterial (IA) injection after osmotic blood brain barrier disruption. In this technique, the therapeutic of interest is injected directly into the arteries that feed the target tissue after the blood brain barrier has been disrupted by exposure to a hyperosmolar mannitol solution, permitting the transluminal transport of the therapy. In this work we used contrast enhanced magnetic resonance imaging (MRI) studies of IA injections in mice to establish parameters that allow for extensive and reproducible BBB disruption. We found that the volume but not the flow rate of the mannitol injection has a significant effect on the degree of disruption. To determine whether the degree of disruption we observed with this method was sufficient for delivery of nanoscale therapeutics, we performed IA injections of an adeno-associated viral vector containing the CLN2 gene (AAVrh.10CLN2), which is mutated in the lysosomal storage disorder Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL). We demonstrated that IA injection of AAVrh.10CLN2 after BBB disruption can achieve widespread transgene production in the mouse brain after a single administration. Further, we showed that there exists a minimum threshold of BBB disruption necessary to permit the AAV.rh10 vector to pass into the brain parenchyma from the vascular system. These results suggest that IA administration may be used to obtain widespread delivery of nanoscale therapeutics throughout the murine brain after a single administration. PMID:25270115

Optimal volume of injectate for fluoroscopy-guided cervical interlaminar epidural injection in patients with neck and upper extremity pain

PubMed Central

Park, Jun Young; Kim, Doo Hwan; Lee, Kunhee; Choi, Seong-Soo; Leem, Jeong-Gil

2016-01-01

Abstract There is no study of optimal volume of contrast medium to use in cervical interlaminar epidural injections (CIEIs) for appropriate spread to target lesions. To determine optimal volume of contrast medium to use in CIEIs. We analyzed the records of 80 patients who had undergone CIEIs. Patients were divided into 3 groups according to the amount of contrast: 3, 4.5, and 6 mL. The spread of medium to the target level was analyzed. Numerical rating scale data were also analyzed. The dye had spread to a point above the target level in 15 (78.9%), 22 (84.6%), and 32 (91.4%) patients in groups 1 to 3, respectively. The dye reached both sides in 14 (73.7%), 18 (69.2%), and 23 (65.7%) patients, and reached the ventral epidural space in 15 (78.9%), 22 (84.6%), and 30 (85.7%) patients, respectively. There were no significant differences of contrast spread among the groups. There were no significant differences in the numerical rating scale scores among the groups during the 3 months. When performing CIEIs, 3 mL medication is sufficient volume for the treatment of neck and upper-extremity pain induced by lower cervical degenerative disease. PMID:27787378

Optimal volume of injectate for fluoroscopy-guided cervical interlaminar epidural injection in patients with neck and upper extremity pain.

PubMed

Park, Jun Young; Kim, Doo Hwan; Lee, Kunhee; Choi, Seong-Soo; Leem, Jeong-Gil

2016-10-01

There is no study of optimal volume of contrast medium to use in cervical interlaminar epidural injections (CIEIs) for appropriate spread to target lesions. To determine optimal volume of contrast medium to use in CIEIs. We analyzed the records of 80 patients who had undergone CIEIs. Patients were divided into 3 groups according to the amount of contrast: 3, 4.5, and 6 mL. The spread of medium to the target level was analyzed. Numerical rating scale data were also analyzed. The dye had spread to a point above the target level in 15 (78.9%), 22 (84.6%), and 32 (91.4%) patients in groups 1 to 3, respectively. The dye reached both sides in 14 (73.7%), 18 (69.2%), and 23 (65.7%) patients, and reached the ventral epidural space in 15 (78.9%), 22 (84.6%), and 30 (85.7%) patients, respectively. There were no significant differences of contrast spread among the groups. There were no significant differences in the numerical rating scale scores among the groups during the 3 months. When performing CIEIs, 3 mL medication is sufficient volume for the treatment of neck and upper-extremity pain induced by lower cervical degenerative disease.

Forecasting magma-chamber rupture at Santorini volcano, Greece

PubMed Central

Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

2015-01-01

How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011–2012 unrest period, that the measured 0.02% increase in volume of Santorini’s shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano. PMID:26507183

Longitudinal 3.0T MRI analysis of changes in lymph node volume and apparent diffusion coefficient in an experimental animal model of metastatic and hyperplastic lymph nodes.

PubMed

Klerkx, Wenche M; Geldof, Albert A; Heintz, A Peter; van Diest, Paul J; Visser, Fredy; Mali, Willem P; Veldhuis, Wouter B

2011-05-01

To perform a longitudinal analysis of changes in lymph node volume and apparent diffusion coefficient (ADC) in healthy, metastatic, and hyperplastic lymph nodes. Three groups of four female Copenhagen rats were studied. Metastasis was induced by injecting cells with a high metastatic potential in their left hind footpad. Reactive nodes were induced by injecting Complete Freund Adjuvant (CFA). Imaging was performed at baseline and at 2, 5, 8, 11, and 14 days after tumor cell injection. Finally, lymph nodes were examined histopathologically. The model was highly efficient in inducing lymphadenopathy: subcutaneous cell or CFA inoculation resulted in ipsilateral metastatic or reactive popliteal lymph nodes in all rats. Metastatic nodal volumes increased exponentially from 5-7 mm(3) at baseline to 25 mm(3) at day 14, while the control node remained 5 mm(3). The hyperplastic nodes showed a rapid volume increase reaching a plateau at day 6. The ADC of metastatic nodes significantly decreased (range 13%-32%), but this decrease was also seen in reactive nodes. Metastatic and hyperplastic lymph nodes differed in terms of enlargement patterns and ADC changes. Enlarged reactive or malignant nodes could not be differentiated based on their ADC values. Copyright © 2011 Wiley-Liss, Inc.

Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice

NASA Astrophysics Data System (ADS)

Evans, Eleanor; Sawiak, Stephen J.; Ward, Alexander O.; Buonincontri, Guido; Hawkes, Robert C.; Adrian Carpenter, T.

2014-01-01

Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time-activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration-time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18F-FDG respectively to ascertain the technique‧s validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.

Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice.

PubMed

Evans, Eleanor; Sawiak, Stephen J; Ward, Alexander O; Buonincontri, Guido; Hawkes, Robert C; Carpenter, T Adrian

2014-01-11

Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time-activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration-time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18 F-FDG respectively to ascertain the technique's validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.

Capillary liquid chromatography combined with pressurized liquid extraction and dispersive liquid-liquid microextraction for the determination of vitamin E in cosmetic products.

PubMed

Viñas, Pilar; Pastor-Belda, Marta; Campillo, Natalia; Bravo-Bravo, María; Hernández-Córdoba, Manuel

2014-06-01

Capillary liquid chromatography (LC) is used for the determination of tocopherols and tocotrienols in cosmetic products. Dispersive liquid-liquid microextraction (DLLME) allows the analytes to be preconcentrated into a very small volume of organic solvent which is then injected into the chromatograph running at a very low flow rate. Pressurized liquid extraction (PLE) at a high temperature and pressure was used to isolate vitamin E forms from cosmetics. The Taguchi experimental method was used to optimize the factors affecting DLLME. The parameters selected were 2mL of acetonitrile (disperser solvent), 100μL carbon tetrachloride (extraction solvent) and 10mL aqueous solution. A volume of 5μL of the organic phase was injected into the reversed-phase capillary LC system equipped with a diode array detector and using an isocratic mobile phase composed of an 95:5 (v/v) methanol:water mixture at a flow-rate of 20μLmin(-1). Quantification was carried out using aqueous standards and detection limits were in the range 0.1-0.5ngmL(-1), corresponding to 3-15ngg(-1) in the cosmetic sample. The recoveries were in the 87-105% range, with RSDs lower than 7.8%. The method was validated according to international guidelines and using a certified reference material. Copyright © 2014 Elsevier B.V. All rights reserved.

Wastewater disposal and the earthquake sequences during 2016 near Fairview, Pawnee, and Cushing, Oklahoma

USGS Publications Warehouse

McGarr, Arthur F.; Barbour, Andrew

2017-01-01

Each of the three earthquake sequences in Oklahoma in 2016—Fairview, Pawnee, and Cushing—appears to have been induced by high-volume wastewater disposal within 10 km. The Fairview M5.1 main shock was part of a 2 year sequence of more than 150 events of M3, or greater; the main shock accounted for about half of the total moment. The foreshocks and aftershocks of the M5.8 Pawnee earthquake were too small and too few to contribute significantly to the cumulative moment; instead, nearly all of the moment induced by wastewater injection was focused on the main shock. The M5.0 Cushing event is part of a sequence that includes 48 earthquakes of M3, or greater, that are mostly foreshocks. The cumulative moment for each of the three sequences during 2016, as well as that for the 2011 Prague, Oklahoma, and nine other sequences representing a broad range of injected volume, are all limited by the total volumes of wastewater injected locally.

Simultaneous determination of the quantity and isotopic signature of dissolved organic matter from soil water using high-performance liquid chromatography/isotope ratio mass spectrometry.

PubMed

Scheibe, Andrea; Krantz, Lars; Gleixner, Gerd

2012-01-30

We assessed the accuracy and utility of a modified high-performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS) system for measuring the amount and stable carbon isotope signature of dissolved organic matter (DOM) <1 µm. Using a range of standard compounds as well as soil solutions sampled in the field, we compared the results of the HPLC/IRMS analysis with those from other methods for determining carbon and (13)C content. The conversion efficiency of the in-line wet oxidation of the HPLC/IRMS averaged 99.3% for a range of standard compounds. The agreement between HPLC/IRMS and other methods in the amount and isotopic signature of both standard compounds and soil water samples was excellent. For DOM concentrations below 10 mg C L(-1) (250 ng C total) pre-concentration or large volume injections are recommended in order to prevent background interferences. We were able to detect large differences in the (13)C signatures of soil solution DOM sampled in 10 cm depth of plots with either C3 or C4 vegetation and in two different parent materials. These measurements also demonstrated changes in the (13)C signature that demonstrate rapid loss of plant-derived C with depth. Overall the modified HLPC/IRMS system has the advantages of rapid sample preparation, small required sample volume and high sample throughput, while showing comparable performance with other methods for measuring the amount and isotopic signature of DOM. Copyright © 2011 John Wiley & Sons, Ltd.

A cadaveric study to determine the minimum volume of methylene blue to completely color the nerves of brachial plexus in cats. An update in forelimb and shoulder surgeries.

PubMed

Mencalha, Rodrigo; Fernandes, Neide; Sousa, Carlos Augusto dos Santos; Abidu-Figueiredo, Marcelo

2014-06-01

To determine the minimum volume of methylene blue (MB) to completely color the brachial plexus (BP) nerves, simulating an effective anesthetic block in cats. Fifteen adult male cat cadavers were injected through subscapular approach with volumes of 2, 3, 4, 5 and 6 ml in both forelimbs, for a total of 30 brachial plexus blocks (BPB). After infusions, the specimens were carefully dissected preserving each nervous branch. The measurement of the effective area was indicated by the impregnation of MB. Nerves were divided into four segments from the origin at the spinal level until the insertion into the thoracic limb muscles. The blocks were considered effective only when all the nerves were strongly or totally colored. Volumes of 2, 3 and 4 ml were considered insufficient suggesting a failed block, however, volumes of 5 and 6 ml were associated with a successful block. The injection of methylene blue, in a volume of 6 ml, completely colored the brachial plexus. At volumes of 5 and 6 ml the brachial plexus blocks were considered a successful regional block, however, volumes of 2, 3 and 4 ml were considered a failed regional block.

Injection molding of iPP samples in controlled conditions and resulting morphology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sessa, Nino, E-mail: ninosessa.ns@gmail.com; De Santis, Felice, E-mail: fedesantis@unisa.it; Pantani, Roberto, E-mail: rpantani@unisa.it

2015-12-17

Injection molded parts are driven down in size and weight especially for electronic applications. In this work, an investigation was carried out on the process of injection molding of thin iPP samples and on the morphology of these parts. Melt flow in the mold cavity was analyzed and described with a mathematical model. Influence of mold temperature and injection pressure was analyzed. Samples orientation was studied using optical microscopy.

Helium ionization detection apparatus

NASA Technical Reports Server (NTRS)

Nagai, R.

1984-01-01

In a gas chromatograph apparatus comprising a gas supply (He carrier gas), a sample injection apparatus, a chromatograph column, a He ion detector, and connecting tubes, a foreign gas (other than He) injection apparatus is installed between the sample injection apparatus and the detector. Mixing of the sample gas and foreign gas takes place readily, the sample gas is always maintained at a stable concentrator range, and accurate measurements are possible, especially at low sample gas concentrations.

Automated tagging of pharmaceutically active thiols under flow conditions using monobromobimane.

PubMed

Tzanavaras, Paraskevas D; Karakosta, Theano D

2011-03-25

The thiol-specific derivatization reagent monobromobimane (MBB) is applied--for the first time--under flow conditions. Sequential injection analysis allows the handling of precise volumes of the reagent in the micro-liter range. The effect of the main chemical and instrumental variables was investigated using captopril (CAP), N-acetylcysteine (NAC) and penicillamine (PEN) as representative pharmaceutically active thiols. Previously reported hydrolysis of MBB due to interaction with nucleophilic components of the buffers was avoided kinetically under flow conditions. The proposed analytical scheme is suitable for the fluorimetric determination of thiols at a sampling rate of 36 h(-1). Copyright © 2010 Elsevier B.V. All rights reserved.

Comparison of pressure-controlled provocation discography using automated versus manual syringe pump manometry in patients with chronic low back pain.

PubMed

Derby, Richard; Lee, Sang Hoon; Lee, Jeong-Eun; Lee, Sang-Heon

2011-01-01

The study compares the rate of positive discograms using an automated versus a manual pressure-controlled injection devise and compares the pressure and volume values at various pressures and initial evoked pain and 6/10 or greater evoked pain. A retrospective study prospectively collected patient study data used in a prior prospective study and with prospectively collected data which is routinely collected per our institutional standardized audit protocol. Two custom-built disc manometers (automated injection speed control; manual injection speed control) were sequentially employed during provocation discography in 510 discs of 151 consecutive patients. Two hundred thirty-seven discs of 67 patients with chronic low back pain were evaluated using the automated manometer (automated group) and 273 discs of 84 patients were evaluated with a manual manometer (manual group). No significant differences in positive discogram rates were found between the automated and manual groups (32.1% vs 32.6% per disc, respectively, P>0.05). No significant differences in low-pressure positive discogram rates were found (16.0% vs 15.0% per disc, automated group versus manual group, respectively, P>0.05). However, there were significantly increased volumes and lower pressures at initial and "bad" pain provocation. The study results found equivalent positive discogram rates following a series of pressure-controlled discography using either an automated or manual pressure devise. There were, however significant increases in volume at both initial onset of evoked pain and at 6/10 pain when using the automated injection devise that may have caused the observed lower opening pressure and lower pressure values at initial evoked pain. Assuming increased volumes are innocuous, automated injection is inherently more controlled and may better reduce unintended and often unrecorded spurious high dynamic pressure peaks thereby reducing conscious and unconscious operator bias. Wiley Periodicals, Inc.

Physical compatibility of various drugs with neonatal total parenteral nutrient solution during simulated Y-site administration.

PubMed

Fox, Laura M; Wilder, Alyson G; Foushee, Jaime A

2013-03-15

The physical compatibility of various drugs with neonatal total parenteral nutrient (TPN) solution during simulated Y-site administration was evaluated. Study drugs were selected based on the lack of compatibility data with them and neonatal TPN solution and the frequency of use in a local neonatal unit. These drugs included amiodarone, caffeine citrate, clindamycin, enalaprilat, epinephrine, fluconazole, fosphenytoin sodium, hydrocortisone, metoclopramide, midazolam, pentobarbital, phenobarbital, and rifampin. Equal volumes of neonatal TPN solution or sterile water for injection were combined with study drugs or sterile water for injection at concentrations used clinically in neonates. Each test was performed in triplicate. The samples were examined via turbidimetric analysis and visually against light and dark backgrounds immediately after mixing and at 0.25, 0.5, 1, 2, and 3 hours after mixing. Analysis of variance was used to determine statistically significant differences between the test and control solutions. Many of the drugs studied exhibited no visual or turbidimetric evidence of incompatibility when combined with neonatal TPN solution for up to three hours in a simulated Y-site injection. Pentobarbital, phenobarbital, and rifampin formed visible precipitation immediately after mixing with the neonatal TPN solution. Caffeine citrate, clindamycin, enalaprilat, epinephrine, fluconazole, fosphenytoin sodium, hydrocortisone, metoclopramide, and midazolam exhibited no visual or turbidimetric evidence of incompatibility when combined with a neonatal TPN solution for up to three hours in a simulated Y-site injection. Amiodarone, pentobarbital, phenobarbital, and rifampin were not compatible with the neonatal TPN solution and should not be coadministered via Y-site injection.

Droplet-based microfluidic flow injection system with large-scale concentration gradient by a single nanoliter-scale injection for enzyme inhibition assay.

PubMed

Cai, Long-Fei; Zhu, Ying; Du, Guan-Sheng; Fang, Qun

2012-01-03

We described a microfluidic chip-based system capable of generating droplet array with a large scale concentration gradient by coupling flow injection gradient technique with droplet-based microfluidics. Multiple modules including sample injection, sample dispersion, gradient generation, droplet formation, mixing of sample and reagents, and online reaction within the droplets were integrated into the microchip. In the system, nanoliter-scale sample solution was automatically injected into the chip under valveless flow injection analysis mode. The sample zone was first dispersed in the microchannel to form a concentration gradient along the axial direction of the microchannel and then segmented into a linear array of droplets by immiscible oil phase. With the segmentation and protection of the oil phase, the concentration gradient profile of the sample was preserved in the droplet array with high fidelity. With a single injection of 16 nL of sample solution, an array of droplets with concentration gradient spanning 3-4 orders of magnitude could be generated. The present system was applied in the enzyme inhibition assay of β-galactosidase to preliminarily demonstrate its potential in high throughput drug screening. With a single injection of 16 nL of inhibitor solution, more than 240 in-droplet enzyme inhibition reactions with different inhibitor concentrations could be performed with an analysis time of 2.5 min. Compared with multiwell plate-based screening systems, the inhibitor consumption was reduced 1000-fold. © 2011 American Chemical Society

Automated Cell-Cutting for Cell Cloning

NASA Astrophysics Data System (ADS)

Ichikawa, Akihiko; Tanikawa, Tamio; Matsukawa, Kazutsugu; Takahashi, Seiya; Ohba, Kohtaro

We develop an automated cell-cutting technique for cell cloning. Animal cells softened by the cytochalasin treatment are injected into a microfluidic chip. The microfluidic chip contains two orthogonal channels: one microchannel is wide, used to transport cells, and generates the cutting flow; the other is thin and used for aspiration, fixing, and stretching of the cell. The injected cell is aspirated and stretched in the thin microchannel. Simultaneously, the volumes of the cell before and after aspiration are calculated; the volumes are used to calculate the fluid flow required to aspirate half the volume of the cell into the thin microchannel. Finally, we apply a high-speed flow in the orthogonal microchannel to bisect the cell. This paper reports the cutting process, the cutting system, and the results of the experiment.

Injectable percutaneous polydimethicone in the treatment of pedal keratomas: a single blind randomized trial.

PubMed

Tollafield, D R; Holdcroft, D J; Singh, R; Haque, M S

2001-01-01

Thirty-one subjects who presented with plantar (metatarsal lesions only 21 out of 31 patients completed the study) completed a single blind injection of 350-centistroke polydimethicone or saline over a 6 to 9-month period. The injectable silicone conformed to European Economic Community standards and was accepted by the Medical Devices Agency (UK). The subjects were equally divided between male and female. Two randomly divided groups received silicone (n = 16) and sterile saline (n = 15). Total volumes used were not identical between the groups of subjects (p = .05), although the maximum volume was no greater than 1.5 ml in any subject. The effectiveness of the injection was reviewed using a Harris-Beath ink mat, visual analogue scale, alteration in frequency of treatment, and subjective analysis of reduction in lesions before and after by color photography. Essential histopathology was undertaken on 11 subjects. Granulomatous reactions were only positively identified in one case. Nine matched pairs showed no statistically significant difference between the two treatments (p = .082) using parametric and nonparametric tests. This study found no evidence to show that small quantities of medically prepared liquid silicone caused adverse reactions, although two cases were more sensitive after injection of silicone.

A low-cost gradient system for high-performance liquid chromatography. Quantitation of complex pharmaceutical raw materials.

PubMed

Erni, F; Frei, R W

1976-09-29

A device is described that makes use of an eight-port motor valve to generate step gradients on the low-pressure side of a piston pump with a low dead volume. Such a gradient device with an automatic control unit, which also permits repetition of previous steps, can be built for about half the cost of a gradient system with two pumps. Applications of this gradient unit to the separation of complex mixtures of glycosides and alkaloids are discussed and compared with separations systems using two high-pressure pumps. The gradients that are used on reversed-phase material with solvent mixtures of water and completely miscible organic solvents are suitable for quantitative routine control of pharmaceutical products. The reproducibility of retention data is excellent over several months and, with the use of loop injectors, major components can be determined quantitatively with a reproducibility of better than 2% (relative standard deviation). The step gradient selector valve can also be used as an introduction system for very large sample volumes. Up to 11 can be injected and samples with concentrations of less than 1 ppb can be determined with good reproducibilities.

A new approach to flow-batch titration. A monosegmented flow titrator with coulometric reagent generation and potentiometric or biamperometric detection.

PubMed

de Aquino, Emerson Vidal; Rohwedder, Jarbas José Rodrigues; Pasquini, Celio

2006-11-01

Monosegmented flow analysis (MSFA) has been used as a flow-batch system to produce a simple, robust, and mechanized titrator that enables true titrations to be performed without the use of standards. This paper also introduces the use of coulometry with monosegmented titration by proposing a versatile flow cell. Coulometric generation of the titrand is attractive for titrations performed in monosegmented systems, because the reagent can be added without increasing the volume of sample injected. Also, biamperomeric and potentiometric detection of titration end-points can increase the versatility of the monosegmented titrator. The cell integrates coulometric generation of the titrand with detection of end-point by potentiometry or biamperometry. The resulting titrator is a flow-batch system in which the liquid monosegment, constrained by the interfaces of the gaseous carrier stream, plays the role of a sample of known volume to be titrated. The system has been used for determination of ascorbic acid, by coulometric generation of I2 with biamperometric detection, and for determination of Fe(II), by coulometric generation of Ce(IV) with potentiometric detection of the end-point, both in feed supplements.

[Onyx embolization for treatment of dural arteriovenous fistula: comparison of long- distance versus routine injection method].

PubMed

He, Xiao-Yan; Zhang, Guo-Zhong; Li, Ming-Zhou; Wang, Gang; Liu, Dan; Qi, Song-Tao; Li, Wei-Guang; Feng, Wen-Feng

2016-03-01

To compare the efficacy, clinical characteristics, safety, injection time and radiation exposure of Onyx embolization using a long-distance injection method and routine injection method for management of dural arteriovenous fistula (DAVF). The clinical data were retrospectively analyzed in 59 patients with DAVF treated with Onyx embolization using long-distance injection method (28 patients) and routine injection method (31 patients). The efficacy, safety, injection time and radiation exposure during Onyx embolization were compared between the two injections methods. The average radiation dose exposure to the surgeon per procedure was significantly lower in the long-distance injection group than in the routine group. The injection time (P=0.53), injection volume (P=0.78), number of supply arteries (P=0.80), Cognard types (P=0.67), and effect of embolization (P=0.88) were all similar between the two groups. Endovaseular treatment of intracranial DAVF with Onyx embolization using the long-distance injection method is feasible, safe and effective and can reduce the radiation exposure to the surgeon.

Acoustic emission of rock mass under the constant-rate fluid injection

NASA Astrophysics Data System (ADS)

Shadrin Klishin, AV, VI

2018-03-01

The authors study acoustic emission in coal bed and difficult-to-cave roof under injection of fluid by pumps at a constant rate. The functional connection between the roof hydrofracture length and the total number of AE pulses is validated, it is also found that the coal bed hydroloosening time, injection rate and time behavior of acoustic emission activity depend on the fluid injection volume required until the fluid breakout in a roadway through growing fractures. In the formulas offered for the practical application, integral parameters that characterize permeability and porosity of rock mass and process parameters of the technology are found during test injection.

Production application of injection-molded diffractive elements

NASA Astrophysics Data System (ADS)

Clark, Peter P.; Chao, Yvonne Y.; Hines, Kevin P.

1995-12-01

We demonstrate that transmission kinoforms for visible light applications can be injection molded in acrylic in production volumes. A camera is described that employs molded Fresnel lenses to change the convergence of a projection ranging system. Kinoform surfaces are used in the projection system to achromatize the Fresnel lenses.

Overcoming the Practical Barriers to Spinal Cord Cell Transplantation for ALS

DTIC Science & Technology

2012-10-01

ABSTRACT: This grant will provide critical data on tolerance and toxicity of cell dosing and numbers of permissible spinal cord injections. Rigorous...Surgical Technique) will provide critical data on tolerance and toxicity of cell dosing and numbers of permissible spinal cord injections. Aim 2 (Graft...connected to a rigid needle of the same gauge as the floating cannula one – Figure 7) using the maximum volume/number of injections could result in

High-rate injection is associated with the increase in U.S. mid-continent seismicity

USGS Publications Warehouse

Weingarten, Matthew; Ge, Shemin; Godt, Jonathan W.; Bekins, Barbara A.; Rubinstein, Justin L.

2015-01-01

An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well’s cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

Further improvement of hydrostatic pressure sample injection for microchip electrophoresis.

PubMed

Luo, Yong; Zhang, Qingquan; Qin, Jianhua; Lin, Bingcheng

2007-12-01

Hydrostatic pressure sample injection method is able to minimize the number of electrodes needed for a microchip electrophoresis process; however, it neither can be applied for electrophoretic DNA sizing, nor can be implemented on the widely used single-cross microchip. This paper presents an injector design that makes the hydrostatic pressure sample injection method suitable for DNA sizing. By introducing an assistant channel into the normal double-cross injector, a rugged DNA sample plug suitable for sizing can be successfully formed within the cross area during the sample loading. This paper also demonstrates that the hydrostatic pressure sample injection can be performed in the single-cross microchip by controlling the radial position of the detection point in the separation channel. Rhodamine 123 and its derivative as model sample were successfully separated.

Large-volume flux closure during plasmoid-mediated reconnection in coaxial helicity injection

DOE PAGES

Ebrahimi, F.; Raman, R.

2016-03-23

A large-volume flux closure during transient coaxial helicity injection (CHI) in NSTX-U is demonstrated through resistive magnetohydrodynamics (MHD) simulations. Several major improvements, including the improved positioning of the divertor poloidal field coils, are projected to improve the CHI start-up phase in NSTX-U. Simulations in the NSTX-U configuration with constant in time coil currents show that with strong flux shaping the injected open field lines (injector flux) rapidly reconnect and form large volume of closed flux surfaces. This is achieved by driving parallel current in the injector flux coil and oppositely directed currents in the flux shaping coils to form amore » narrow injector flux footprint and push the injector flux into the vessel. As the helicity and plasma are injected into the device, the oppositely directed field lines in the injector region are forced to reconnect through a local Sweet-Parker type reconnection, or to spontaneously reconnect when the elongated current sheet becomes MHD unstable to form plasmoids. In these simulations for the first time, it is found that the closed flux is over 70% of the initial injector flux used to initiate the discharge. Furthermore, these results could work well for the application of transient CHI in devices that employ super conducting coils to generate and sustain the plasma equilibrium.« less

Determination of picomolar concentrations of carbonyl compounds in natural waters, including seawater, by liquid chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kieber, R.; Mopper, K.

1990-10-01

Low molecular weight carbonyl compounds in natural waters were determined at picomolar to nanomolar levels by derivatization with 2,4-dinitrophenylhydrazine followed by liquid chromatography. The uniqueness of the method is attributed to the extremely low blanks obtained and the minimal sample preparation involved. The detection limit for direct injection of derivatized natural water samples is 0.5 nM for aldehydes and 5 nM for ketones with a precision of {approximately}7% RSD at the 30 nM level for aldehydes. The detection limit can be further lowered by using off-line cartridge enrichment in which derivatized natural water is passed through a C18 extraction cartridge.more » Recoveries for the enrichment method were 95-105% for a sample volume of 20 mL and for concentrations of carbonyl compounds in the 1-30 nM range. A field procedure for storage of derivatized sample extracts for extended periods is also presented. Applications of enrichment and sample storage techniques to marine and estuarine waters are presented.« less

Phase 1 and 2 studies demonstrate the safety and efficacy of intraprostatic injection of PRX302 for the targeted treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia.

PubMed

Denmeade, Samuel R; Egerdie, Blair; Steinhoff, Gary; Merchant, Rosemina; Abi-Habib, Ralph; Pommerville, Peter

2011-05-01

PRX302 is a prostate specific antigen (PSA)-activated pore-forming protein toxin under development as a targeted approach for improving lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) without affecting sexual function. To evaluate the safety and efficacy of PRX302 in men with moderate to severe BPH. Eligible subjects were refractory, intolerant, or unwilling to undergo medical therapies for BPH and had International Prostate Symptom Score (IPSS) ≥12, a quality of life (QoL) score ≥3, and prostate volumes between 30 and 80 g. Fifteen patients were enrolled in phase 1 studies, and 18 patients entered phase 2 studies. Subjects received intraprostatic injection of PRX302 into the right and left transition zone via a transperineal approach in an office-based setting. Phase 1 subjects received increasing concentrations of PRX302 at a fixed volume; phase 2 subjects received increasing volumes per deposit at a fixed concentration. IPSS, QoL, prostate volume, maximum flow rate (Q(max)), International Index of Erectile Function, serum PSA levels, pharmacokinetics, and adverse events were recorded at 30, 60, 90, 180, 270, and 360 d after treatment with PRX302. Sixty percent of men in the phase 1 study and 64% of men in the phase 2 study treated with PRX302 had ≥30% improvement compared to baseline in IPSS out to day 360. Patients also experienced improvement in QoL and reduction in prostate volume out to day 360. Patients receiving ≥1 ml of PRX302 per deposit had the best response overall. PRX302 had no deleterious effect on erectile function. Adverse events were mild to moderate and transient in nature. The major study limitation was the small sample size. The promising safety profile and evidence of efficacy in the majority of treated subjects in these phase 1 and 2 studies supports further development of PRX302 as a minimally invasive, targeted treatment for BPH. Copyright © 2010 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Quantitative Discomanometry: Correlation of Intradiscal Pressure Values to Pain Reduction in Patients With Intervertebral Disc Herniation Treated With Percutaneous, Minimally Invasive, Image-Guided Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filippiadis, Dimitrios K., E-mail: dfilippiadis@yahoo.gr; Mazioti, A., E-mail: argyromazioti@yahoo.gr; Papakonstantinou, O., E-mail: sogofianol@gmail.com

Purpose: To illustrate quantitative discomanometry's (QD) diagnostic efficacy and predictive value in discogenic-pain evaluation in a prospective study correlating intradiscal pressure values with pain reduction after percutaneous image-guided technique (i.e., percutaneous decompression, PD). Materials and Methods: During the last 3 years, 36 patients [21 male and 15 female (mean age 36 {+-} 5.8 years)] with intervertebral disc hernia underwent QD before PD. Under absolute sterilization and fluoroscopy, a mixture of contrast medium and normal saline (3:1 ratio) was injected. A discmonitor performed a constant rate injection and recorded pressure and volume values, thus producing the relative pressure-volume curve. PD wasmore » then performed. Pain reduction and improved mobility were recorded at 3, 12, and 24 months after PD using clinical evaluation and a numeric visual scale (NVS; 0 to 10 units). Results: Mean pain values of 7.5 {+-} 1.9 (range 4 to 8) NVS units were recorded before PD; these decreased to 2.9 {+-} 2.44 at 3 months, 1.0 {+-} 1.9 at 12 months, and 1.0 {+-} 1.9 NVS units at 24 months after PD. Recorded correlations (pressure, volume, significant pain-reduction values) with bilateral statistical significance included a maximum injected volume of 2.4 ml (p = 0.045), P{sub o} < 14 psi [initial pressure required to inject 0.1 ml of the mixture inside the disc (p = 0.05)], P{sub max} {<=} 65 psi [greatest pressure value on the curve (p = 0.018)], and P{sub max} - P{sub o} {<=} 47 psi (p = 0.038). Patients meeting these pressure or volume cut-off points, either independently or as a total, had significant pain reduction (>4 NVS units) after PD. No complications were noted. Conclusions: QD is an efficient technique that may have predictive value for discogenic pain evaluation. It might serve as a useful tool for patient selection for intervertebral disc therapies.« less

Combination of dispersive liquid-liquid microextraction with flame atomic absorption spectrometry using microsample introduction for determination of lead in water samples.

PubMed

Naseri, Mohammad Taghi; Hemmatkhah, Payam; Hosseini, Mohammad Reza Milani; Assadi, Yaghoub

2008-03-03

The dispersive liquid-liquid microextraction (DLLME) was combined with the flame atomic absorption spectrometry (FAAS) for determination of lead in the water samples. Diethyldithiophosphoric acid (DDTP), carbon tetrachloride and methanol were used as chelating agent, extraction solvent and disperser solvent, respectively. A new FAAS sample introduction system was employed for the microvolume nebulization of the non-flammable chlorinated organic extracts. Injection of 20 microL volumes of the organic extract into an air-acetylene flame provided very sensitive spike-like and reproducible signals. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters include extraction and disperser solvent type as well as their volume, extraction time, salt effect, pH and amount of the chelating agent. Under the optimized conditions, the enrichment factor of 450 was obtained from a sample volume of 25.0 mL. The enhancement factor, calculated as the ratio of the slopes of the calibration graphs with and without preconcentration, which was about 1000. The calibration graph was linear in the range of 1-70 microgL(-1) with a detection limit of 0.5 microgL(-1). The relative standard deviation (R.S.D.) for seven replicate measurements of 5.0 and 50 microgL(-1) of lead were 3.8 and 2.0%, respectively. The relative recoveries of lead in tap, well, river and seawater samples at the spiking level of 20 microgL(-1) ranged from 93.8 to 106.2%. The characteristics of the proposed method were compared with those of the liquid-liquid extraction (LLE), cloud point extraction (CPE), on-line and off-line solid-phase extraction (SPE) as well as co-precipitation, based on bibliographic data. Operation simplicity, rapidity, low cost, high enrichment factor, good repeatability, and low consumption of the extraction solvent at a microliter level are the main advantages of the proposed method.

In-port derivatization coupled to different extraction techniques for the determination of alkylphenols in environmental water samples.

PubMed

Cavalheiro, J; Monperrus, M; Amouroux, D; Preud'Homme, H; Prieto, A; Zuloaga, O

2014-05-02

Large volume injection (LVI)-in port silylation coupled to gas chromatography-mass spectrometry (GC-MS) for the determination of alkylphenols (APs) in water samples applying four different extraction approaches was evaluated. Among the variables studied for in-port derivatization, vent time, cryo-focusing temperature and the ratio solvent volume/N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) volume were optimized using an experimental design approach. Regarding the extraction techniques, different approaches previously optimized in the research group were tested. On the one hand different polymeric materials were tested: silicon rod (SR), polyethersulfone (PES) and polydimethylsiloxane (PDMS), the latter in the stir-bar sorptive extraction format (SBSE-PDMS). PES was chosen among the polymeric materials due to the higher recoveries (compared with SR) and lower price (compared to PDMS in the stir-bar sorptive extraction, SBSE-PDMS). Both MASE and PES protocols were selected at this point for further method validation and application to real samples. Finally, the developed methods were validated and applied to the determination of target analytes in various aqueous environmental matrices, including estuarine water and wastewater. Acceptable repeatability in the case of MASE (5-17%) and PES (7-21%) procedures and method detection limits (MDLs, 5-123 and 28-328 ng L(-1) for PES and MASE, respectively) were obtained for most analytes. In terms of apparent recoveries in the presence of matrix, estuarine and effluent samples showed no significant matrix effect (apparent recoveries in the 73-121% for PES and 74-128% for MASE), while a stronger matrix effect was observed for influent wastewater samples (98-132% for PES and 65-156% for MASE). Both MASE and PES extractions combined with LVI-in-port derivatization-GC-MS were applied to the determination of APs in the estuary of Bilbao (Gulf of Biscay, Spain). Copyright © 2014 Elsevier B.V. All rights reserved.

The renal compartment: a hydraulic view.

PubMed

Cruces, Pablo; Salas, Camila; Lillo, Pablo; Salomon, Tatiana; Lillo, Felipe; Hurtado, Daniel E

2014-12-01

The hydraulic behavior of the renal compartment is poorly understood. In particular, the role of the renal capsule on the intrarenal pressure has not been thoroughly addressed to date. We hypothesized that pressure and volume in the renal compartment are not linearly related, similar to other body compartments. The pressure-volume curve of the renal compartment was obtained by injecting fluid into the renal pelvis and recording the rise in intrarenal pressure in six anesthetized and mechanically ventilated piglets, using a catheter Camino 4B® inserted into the renal parenchyma. In healthy kidneys, pressure has a highly nonlinear dependence on the injected volume, as revealed by an exponential fit to the data (R (2) = 0.92). On the contrary, a linear relation between pressure and volume is observed in decapsulated kidneys. We propose a biomechanical model for the renal capsule that is able to explain the nonlinear pressure-volume dependence for moderate volume increases. We have presented experimental evidence and a theoretical model that supports the existence of a renal compartment. The mechanical role of the renal capsule investigated in this work may have important implications in elucidating the role of decompressive capsulotomy in reducing the intrarenal pressure in acutely injured kidneys.

Resolving the Detailed Structure of Cortical and Thalamic Neurons in the Adult Rat Brain with Refined Biotinylated Dextran Amine Labeling

PubMed Central

Ling, Changying; Hendrickson, Michael L.; Kalil, Ronald E.

2012-01-01

Biotinylated dextran amine (BDA) has been used frequently for both anterograde and retrograde pathway tracing in the central nervous system. Typically, BDA labels axons and cell somas in sufficient detail to identify their topographical location accurately. However, BDA labeling often has proved to be inadequate to resolve the fine structural details of axon arbors or the dendrites of neurons at a distance from the site of BDA injection. To overcome this limitation, we varied several experimental parameters associated with the BDA labeling of neurons in the adult rat brain in order to improve the sensitivity of the method. Specifically, we compared the effect on labeling sensitivity of: (a) using 3,000 or 10,000 MW BDA; (b) injecting different volumes of BDA; (c) co-injecting BDA with NMDA; and (d) employing various post-injection survival times. Following the extracellular injection of BDA into the visual cortex, labeled cells and axons were observed in both cortical and thalamic areas of all animals studied. However, the detailed morphology of axon arbors and distal dendrites was evident only under optimal conditions for BDA labeling that take into account the: molecular weight of the BDA used, concentration and volume of BDA injected, post-injection survival time, and toning of the resolved BDA with gold and silver. In these instances, anterogradely labeled axons and retrogradely labeled dendrites were resolved in fine detail, approximating that which can be achieved with intracellularly injected compounds such as biocytin or fluorescent dyes. PMID:23144777

Multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy for image-guided feedback of intraocular injections in mouse models

NASA Astrophysics Data System (ADS)

Benavides, Oscar R.; Terrones, Benjamin D.; Leeburg, Kelsey C.; Mehanathan, Sankarathi B.; Levine, Edward M.; Tao, Yuankai K.

2018-02-01

Rodent models are robust tools for understanding human retinal disease and function because of their similarities with human physiology and anatomy and availability of genetic mutants. Optical coherence tomography (OCT) has been well-established for ophthalmic imaging in rodents and enables depth-resolved visualization of structures and image-based surrogate biomarkers of disease. Similarly, fluorescence confocal scanning laser ophthalmoscopy (cSLO) has demonstrated utility for imaging endogenous and exogenous fluorescence and scattering contrast in the mouse retina. Complementary volumetric scattering and en face fluorescence contrast from OCT and cSLO, respectively, enables cellular-resolution longitudinal imaging of changes in ophthalmic structure and function. We present a non-contact multimodal OCT+cSLO small animal imaging system with extended working distance to the pupil, which enables imaging during and after intraocular injection. While injections are routinely performed in mice to develop novel models of ophthalmic diseases and screen novel therapeutics, the location and volume delivered is not precisely controlled and difficult to reproduce. Animals were imaged using a custom-built OCT engine and scan-head combined with a modified commercial cSLO scan-head. Post-injection imaging showed structural changes associated with retinal puncture, including the injection track, a retinal elevation, and detachment of the posterior hyaloid. When combined with imagesegmentation, we believe OCT can be used to precisely identify injection locations and quantify injection volumes. Fluorescence cSLO can provide complementary contrast for either fluorescently labeled compounds or transgenic cells for improved specificity. Our non-contact OCT+cSLO system is uniquely-suited for concurrent imaging with intraocular injections, which may be used for real-time image-guided injections.

Dermal Filler Injection: A Novel Approach for Limiting Infarct Expansion

PubMed Central

Ryan, Liam P.; Matsuzaki, Kanji; Noma, Mio; Jackson, Benjamin M.; Eperjesi, Thomas J.; Plappert, Theodore J.; St. John-Sutton, Martin G.; Gorman, Joseph H.; Gorman, Robert C.

2011-01-01

Background Early infarct expansion after coronary occlusion compromises contractile function in perfused myocardial regions and promotes adverse long-term left ventricular (LV) remodeling. We hypothesized that injection of a tissue-expanding dermal filler material into a myocardial infarction (MI) would attenuate infarct expansion and limit LV remodeling. Methods Fifteen sheep were subjected to an anteroapical MI involving approximately 20% of the LV followed by the injection of 1.3 mL of a calcium hydroxyapatite–based dermal filler into the infarct. Real-time three-dimensional echocardiography was performed at baseline, 30 minutes after MI, and 15 minutes after injection to assess infarct expansion. Sixteen additional sheep were subjected to the same infarction and followed echocardiographically and hemodynamically for 4 weeks after MI to assess chronic remodeling. Eight animals had injection with dermal filler as described above immediately after MI, and 8 animals were injected with an equal amount of saline solution. Results All animals exhibited infarct expansion soon after coronary occlusion. The regional ejection fraction of the apex became negative after infarction, consistent with systolic dyskinesia. Injection of the dermal filler converted the apical wall motion from dyskinetic to akinetic and resulted immediately in significant decreases in global, regional, and segmental LV volumes. Chronically, relative to saline control, dermal filler injection significantly reduced LV end-systolic volume (62.2 ± 3.6 mL versus 44.5 ± 3.9 mL; p < 0.05) and improved global ejection fraction (0.295 ± 0.016 versus 0.373 ± 0.017; p < 0.05) at 4 weeks after infarction. Conclusions Injection of an acellular dermal filler into an MI immediately after coronary occlusion reduces early infarct expansion and limits chronic LV remodeling. PMID:19101288

ELECTRICALLY ACTUATED, PRESSURE-DRIVEN LIQUID CHROMATOGRAPHY SEPARATIONS IN MICROFABRICATED DEVICES

PubMed Central

Fuentes, Hernan V.; Woolley, Adam T.

2012-01-01

Electrolysis-based micropumps integrated with microfluidic channels in micromachined glass substrates are presented. Photolithography combined with wet chemical etching and thermal bonding enabled the fabrication of multi-layer devices containing electrically actuated micropumps interfaced with sample and mobile phase reservoirs. A stationary phase was deposited on the microchannel walls by coating with 10% (w/w) chlorodimethyloctadecylsilane in toluene. Pressure-balanced injection was implemented by controlling the electrolysis time and voltage applied in the two independent micropumps. Current fluctuations in the micropumps due to the stochastic formation of bubbles on the electrode surfaces were determined to be the main cause of variation between separations. On-chip electrochemical pumping enabled the loading of pL samples with no dead volume between injection and separation. A mobile phase composed of 70% acetonitrile and 30% 50 mM acetate buffer (pH 5.45) was used for the chromatographic separation of three fluorescently labeled amino acids in <40 s with an efficiency of >3000 theoretical plates in a 2.5-cm-long channel. Our results demonstrate the potential of electrochemical micropumps integrated with microchannels to perform rapid chromatographic separations in a microfabricated platform. Importantly, these devices represent a significant step toward the development of miniaturized and fully integrated liquid chromatography systems. PMID:17960281

Electrically actuated, pressure-driven liquid chromatography separations in microfabricated devices.

PubMed

Fuentes, Hernan V; Woolley, Adam T

2007-11-01

Electrolysis-based micropumps integrated with microfluidic channels in micromachined glass substrates are presented. Photolithography combined with wet chemical etching and thermal bonding enabled the fabrication of multi-layer devices containing electrically actuated micropumps interfaced with sample and mobile phase reservoirs. A stationary phase was deposited on the microchannel walls by coating with 10% (w/w) chlorodimethyloctadecylsilane in toluene. Pressure-balanced injection was implemented by controlling the electrolysis time and voltage applied in the two independent micropumps. Current fluctuations in the micropumps due to the stochastic formation of bubbles on the electrode surfaces were determined to be the main cause of variation between separations. On-chip electrochemical pumping enabled the loading of pL samples with no dead volume between injection and separation. A mobile phase composed of 70% acetonitrile and 30% 50 mM acetate buffer (pH 5.45) was used for the chromatographic separation of three fluorescently labeled amino acids in <40 s with an efficiency of >3000 theoretical plates in a 2.5 cm-long channel. Our results demonstrate the potential of electrochemical micropumps integrated with microchannels to perform rapid chromatographic separations in a microfabricated platform. Importantly, these devices represent a significant step toward the development of miniaturized and fully integrated liquid chromatography systems.

CO 2 Mineral Sequestration in Naturally Porous Basalt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiong, Wei; Wells, Rachel K.; Horner, Jake A.

2018-02-27

Continental flood basalts are extensive geologic features currently being evaluated as reservoirs that are suitable for long-term storage of carbon emissions. Favorable attributes of these formations for containment of injected carbon dioxide (CO2) include high mineral trapping capacity, unique structural features, and enormous volumes. We experimentally investigated mineral carbonation in whole core samples retrieved from the Grand Ronde basalt, the same formation into which ~1000 t of CO2 was recently injected in an eastern Washington pilot-scale demonstration. The rate and extent of carbonate mineral formation at 100 °C and 100 bar were tracked via time-resolved sampling of bench-scale experiments. Basaltmore » cores were recovered from the reactor after 6, 20, and 40 weeks, and three-dimensional X-ray tomographic imaging of these cores detected carbonate mineral formation in the fracture network within 20 weeks. Under these conditions, a carbon mineral trapping rate of 1.24 ± 0.52 kg of CO2/m3 of basalt per year was estimated, which is orders of magnitude faster than rates for deep sandstone reservoirs. On the basis of these calculations and under certain assumptions, available pore space within the Grand Ronde basalt formation would completely carbonate in ~40 years, resulting in solid mineral trapping of ~47 kg of CO2/m3 of basalt.« less

Solvent viscosity mismatch between the solute plug and the mobile phase: Considerations in the applications of two-dimensional HPLC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shalliker, R. Andrew; Guiochon, Georges A

Understanding the nature of viscosity contrast induced flow instabilities is an important aspect in the design of two-dimensional HPLC separations. When the viscosity contrast between the sample plug and the mobile phase is sufficiently large, the phenomenon known as viscous fingering can be induced. Viscous fingering is a flow instability phenomenon that occurs at the interface between two fluids with different viscosities. In liquid chromatography, viscous fingering results in the solute band undergoing a change in form as it enters into the chromatography column. Moreover, even in the absence of viscous fingering, band shapes change shape at low viscosity contrasts.more » These changes can result in a noticeable change in separation performance, with the result depending on whether the solvent pushing the solute plug has a higher or lower viscosity than the solute plug. These viscosity induced changes become more important as the solute injection volume increases and hence understanding the process becomes critical in the implementation of multidimensional HPLC techniques, since in these techniques the sample injection plug into the second dimension is an order of magnitude greater than in one-dimensional HPLC. This review article assesses the current understanding of the viscosity contrast induced processes as they relate to liquid chromatographic separation behaviour.« less

Gas injection may have triggered earthquakes in the Cogdell oil field, Texas

PubMed Central

Gan, Wei; Frohlich, Cliff

2013-01-01

Between 1957 and 1982, water flooding was conducted to improve petroleum production in the Cogdell oil field north of Snyder, TX, and a contemporary analysis concluded this induced earthquakes that occurred between 1975 and 1982. The National Earthquake Information Center detected no further activity between 1983 and 2005, but between 2006 and 2011 reported 18 earthquakes having magnitudes 3 and greater. To investigate these earthquakes, we analyzed data recorded by six temporary seismograph stations deployed by the USArray program, and identified 93 well-recorded earthquakes occurring between March 2009 and December 2010. Relocation with a double-difference method shows that most earthquakes occurred within several northeast–southwest-trending linear clusters, with trends corresponding to nodal planes of regional focal mechanisms, possibly indicating the presence of previously unidentified faults. We have evaluated data concerning injection and extraction of oil, water, and gas in the Cogdell field. Water injection cannot explain the 2006–2011 earthquakes, especially as net volumes (injection minus extraction) are significantly less than in the 1957–1982 period. However, since 2004 significant volumes of gases including supercritical CO2 have been injected into the Cogdell field. The timing of gas injection suggests it may have contributed to triggering the recent seismic activity. If so, this represents an instance where gas injection has triggered earthquakes having magnitudes 3 and larger. Further modeling studies may help evaluate recent assertions suggesting significant risks accompany large-scale carbon capture and storage as a strategy for managing climate change. PMID:24191019

Potentially induced earthquakes in Oklahoma, USA: links between wastewater injection and the 2011 Mw 5.7 earthquake sequence

USGS Publications Warehouse

Keranen, Katie M.; Savage, Heather M.; Abers, Geoffrey A.; Cochran, Elizabeth S.

2013-01-01

Significant earthquakes are increasingly occurring within the continental interior of the United States, including five of moment magnitude (Mw) ≥ 5.0 in 2011 alone. Concurrently, the volume of fluid injected into the subsurface related to the production of unconventional resources continues to rise. Here we identify the largest earthquake potentially related to injection, an Mw 5.7 earthquake in November 2011 in Oklahoma. The earthquake was felt in at least 17 states and caused damage in the epicentral region. It occurred in a sequence, with 2 earthquakes of Mw 5.0 and a prolific sequence of aftershocks. We use the aftershocks to illuminate the faults that ruptured in the sequence, and show that the tip of the initial rupture plane is within ~200 m of active injection wells and within ~1 km of the surface; 30% of early aftershocks occur within the sedimentary section. Subsurface data indicate that fluid was injected into effectively sealed compartments, and we interpret that a net fluid volume increase after 18 yr of injection lowered effective stress on reservoir-bounding faults. Significantly, this case indicates that decades-long lags between the commencement of fluid injection and the onset of induced earthquakes are possible, and modifies our common criteria for fluid-induced events. The progressive rupture of three fault planes in this sequence suggests that stress changes from the initial rupture triggered the successive earthquakes, including one larger than the first.