Relevant bibliographies by topics / Column injection / Journal articles

To see the other types of publications on this topic, follow the link: Column injection.

Journal articles on the topic 'Column injection'

Author: Grafiati

Published: 9 March 2023

Last updated: 19 July 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Column injection.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

Wylie, Philip, and Katsura Uchiyama. "Improved Gas Chromatographic Analysisof Organophosphorus Pesticides with Pulsed Splitless Injectiony." Journal of AOAC INTERNATIONAL 79, no. 2 (1996): 571–78. http://dx.doi.org/10.1093/jaoac/79.2.571.

Full text

Abstract:

Abstract Gas chromatographic (GC) analysis of 6 organo-phosphorus pesticides (methamidophos, acephate, omethoate, diazinon, dimethoate, and chlorpyrifos) was performed with cool on-column, splitless, and pulsed splitless injections and with nitrogen–phos phorus or mass-selective detection. The pulsed splitless technique uses a high column flow rate during injection to sweep the sample out of the inlet rapidly, reducing analyte loss due to adsorption or thermal decomposition. After injection, the column flow rate is automatically reduced to normal values for chromatographic analysis. Pesticide recoveries for splitless and pulsed splitless injections were determined by comparison of GC peak areas with those obtained with cool on-column injection. With conventional splitless injection at a column flow rate of 5 mL/min, recoveries of acephate, omethoate, and methamidophos were only 57, 63, and 71 %, respectively. Pulsed splitless methods with very fast injection flow rates dramatically improved recoveries, with all 6 pesticides falling in the 97–102% range. Because column flow rates are much less for GC with mass spectral detection (GC/MS), recoveries with splitless injection were lower and improvements with pulsed splitless injection were less dramatic for GC/MS. When splitless injection was used, recoveries of the 6 pesticides spiked into a green bean matrix were better than those of pesticides dissolved in pure solvent, presumably because matrix compounds compete with pesticides for active sites in the inlet. By using pulsed splitless injection of solvent standards with very fast initial column flow rates, systematic analyte losses in the inlet were eliminated, making recoveries of pesticides from solvent and green bean matrix very similar.

APA, Harvard, Vancouver, ISO, and other styles

Hopper, Marvin L. "Analysis of Organochlorine Pesticide Residues Using Simultaneous Injection of Two Capillary Columns with Electron Capture and Electrolytic Conductivity Detectors." Journal of AOAC INTERNATIONAL 74, no. 6 (1991): 974–81. http://dx.doi.org/10.1093/jaoac/74.6.974.

Full text

Abstract:

Abstract A system has been developed that will allow low level screening of 31 organochlorine pesticide residues using simultaneous injection on 2 dissimilar capillary columns. An electron capture detector was attached to a DB-1701 column, and an electrolytic conductivity detector in the halogen mode was attached to a DB-5 column. Chlorinated pesticide amounts ranging from 0.05 ng for γ-BHC to 1.5 ng for decamethrin can easily be quantitated and confirmed. The system can be used in either the column programmed mode or the isothermal column mode. Good reproducibility was obtained for injections in both modes. This system can easily be retrofitted to any gas chromatograph using on column or split/splitless injectors.

APA, Harvard, Vancouver, ISO, and other styles

Watanabe, Chuichi, and Keiji Hashimoto. "Direct injection of large sample volumes into capillary columns with packed column injector." Journal of High Resolution Chromatography 13, no. 9 (1990): 610–13. http://dx.doi.org/10.1002/jhrc.1240130905.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Gong, Ya-Nan, Qi-Yu Ma, Ying Wang, et al. "Preparation of Chiral Porous Organic Cage Clicked Chiral Stationary Phase for HPLC Enantioseparation." Molecules 28, no. 7 (2023): 3235. http://dx.doi.org/10.3390/molecules28073235.

Full text

Abstract:

Porous organic cages (POCs) are a new subclass of porous materials, which are constructed from discrete cage molecules with permanent cavities via weak intermolecular forces. In this study, a novel chiral stationary phase (CSP) has been prepared by chemically binding a [4 + 6]-type chiral POC (C120H96N12O4) with thiol-functionalized silica gel using a thiol-ene click reaction and applied to HPLC separations. The column packed with this CSP presented good separation capability for chiral compounds and positional isomers. Thirteen racemates have been enantioseparated on this column, including alcohols, diols, ketones, amines, epoxides, and organic acids. Upon comparison with a previously reported chiral POC NC1-R-based column, commercial Chiralpak AD-H, and Chiralcel OD-H columns, this column is complementary to these three columns in terms of its enantiomeric separation; and can also separate some racemic compounds that cannot be separated by the three columns. In addition, eight positional isomers (iodoaniline, bromoaniline, chloroaniline, dibromobenzene, dichlorobenzene, toluidine, nitrobromobenzene, and nitroaniline) have also been separated. The influences of the injection weight and column temperature on separation have been explored. After the column has undergone multiple injections, the relative standard deviations (RSDs) for the retention time and selectivity were below 1.0 and 1.5%, respectively, indicating the good reproducibility and stability of the column for separation. This work demonstrates that POCs are promising materials for HPLC separation.

APA, Harvard, Vancouver, ISO, and other styles

Ma, R., and Yan Xiao. "Seismic Retrofit and Repair of Circular Bridge Columns with Advanced Composite Materials." Earthquake Spectra 15, no. 4 (1999): 747–64. http://dx.doi.org/10.1193/1.1586070.

Full text

Abstract:

Experimental studies on seismic retrofit and repair of typical circular bridge columns with poor lap splice details utilizing prefabricated glass fiber reinforced polymer (FRP) composite jackets and epoxy are presented in this paper. A total of seven tests on three 1/2-scale model columns were conducted. One column was tested under “as-built” condition and the other two columns were retrofitted with prefabricated composite individual and continuous jackets respectively. The jackets were applied in the potential plastic hinge region of the column to increase its lateral confinement. Brittle failure was observed in the “as-built” model column due to the bond deterioration of lap spliced longitudinal reinforcement. This brittle failure was prevented in the retrofitted columns. The repairing of failed “as-built” column by injecting epoxy into damaged plastic region resulted in significant stiffening of the portion and increase of capacity and ductility. The second repair of the specimen using both epoxy injection and prefabricated composite jacketing effectively improved its behavior further. The results of this study indicated that dramatic improvement in ductility and energy absorption capacity of columns can be achieved using these retrofit and repair methods.

APA, Harvard, Vancouver, ISO, and other styles

Irfan, Hafeez* Muhammad Azam Zahid Mahmood Athar Amin Muhammad Aamir Adnan Akram. "RAPID ESTIMATION OF PHOSPHOLIPED BY IMMOBILIZED PHOSPHOLIPASE D FROM PISTACHIA KHINJUK IN FIA SYSTEM." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 6, no. 3 (2017): 356–62. https://doi.org/10.5281/zenodo.400976.

Full text

Abstract:

Blue green gains of Pistachia khinjuk was collected from area of Harnai Balochistan and crude Phospholipase D was isolated by simple protean precipitation. This enzyme was covalently bounded on the surface of controlled porosity glass beads and packed in small glass columns. Immobilized PLD was used for quantitative determination of Phosphatidylcholine (Lecithin) and Phosphorylcholine in flow-injection analysis system. Immobilized columns of Phospholipase C from rice and Choline oxidase from chicken intestine were also prepared in same manner. The phosphatidylcholine was estimated by incorporation PLD column fallowed by choline oxidase column in flow stream. The resultant hydrogen peroxide produced as byproduct in flow injection system was detected amperometrically by electrochemical hydrogen per oxide detector. The Phosphorylcholine was estimated by insertion of PLC column in FIA system and final product was estimated using spectrophotometer at λ Max 640 nm. The isolated PLD showed rapid accuracy for estimation of lecithin and using immobilized PLC fallowed by Alkaline phosphatase found best for Phosphorylcholine estimation.

APA, Harvard, Vancouver, ISO, and other styles

Kehr, Ján, and Mikuláš Chavko. "Protection, efficiency, and some practical aspects of use of CGC columns in high performance liquid chromatography." Collection of Czechoslovak Chemical Communications 51, no. 10 (1986): 2091–97. http://dx.doi.org/10.1135/cccc19862091.

Full text

Abstract:

Some practical adaptations of compact glass cartridge (CGC) columns and design of related components of the high-performance liquid chromatographic system are suggested; included are the design of a Teflon guard column and its filling procedure, an intra-column sample injector for on-column sample delivery or for injection into the precolumn, replacement of a contaminated packing or replenishment of packing at the top of the CGC column, a procedure for shortening the column to a desired length, and the possibility of thermostatting the column by means of a water jacket. These adaptations make it possible to increase the lifetime of the CGC column as much as five times without loss of efficiency, and to use partly damaged or imperfectly packed columns.

APA, Harvard, Vancouver, ISO, and other styles

Parfitt, Charles H. "Wide-Bore Capillary Gas Chromatographic Determination of Organophosphorus Pesticide Residues in Foods: Interlaboratory Trial." Journal of AOAC INTERNATIONAL 77, no. 1 (1994): 92–101. http://dx.doi.org/10.1093/jaoac/77.1.92.

Full text

Abstract:

Abstract Wide-Bore capillary columns are often used as alternatives to traditionally packed columns for gas chromatographic (GC) determination of pesticide residues in foods. Fused silica columns with cross-linked, bonded stationary phases are reproducible, rugged, and easy to use and are substantially more inert than their packed column equivalents. An interlaboratory trial was conducted in 5 U.S. Food and Drug Administration laboratories to determine the practicability of using isothermal wide-bore capillary GC as an alternative to the packed column GC systems used in AOAC Official Methods for determining pesticide residues in foods. Two wide-bore capillary columns with flame photometric detection were evaluated with respect to the following: linearity of detector response; repeatability of response for equal and unequal injection volumes of standard solutions; accuracy of quantitating pesticides in food extracts when the injection volumes or analyte concentrations of the standard solution and the food extract are different; recoveries of 23 pesticides from 5 fortified food extracts, calculated from both duplicate and single injections; and relative retention times. Before shipment, food extracts supplied to participants were fortified with pesticides after preparation and extraction of the foods by Official Method 985.22. The performance of wide-bore capillary columns with cross-linked bonded methyl silicone and methyl phenyl silicone stationary phases was equal or superior to that of the packed columns specified in the Official Method.

APA, Harvard, Vancouver, ISO, and other styles

Dadonova, Anna, Ivan Yakoviv, and Valerii Kozlovskiy. "Method of protection of database management systems against sql-identifier injection attacks." Science-based technologies 52, no. 4 (2021): 305–12. http://dx.doi.org/10.18372/2310-5461.52.16385.

Full text

Abstract:

The article reviews SQL injection and SQL identifier injection attacks in database management systems, identifies their nature, the threats they pose, and the types of these attacks. A new method of protecting database management systems from SQL identifier injection attacks is also covered. Proposed solution are functions that can be added to the prepared API statements: setColumnName: uses the column name and its index as arguments and setTableName: uses the table name and its index as arguments. This method allows you to prepare operators to fill placeholders with table and column names, prevents SQL-IDIA, does not skip schema information, has no restrictions on input-based sanitation approaches. These two features help prevent database management systems from leaking confidential database information by performing a default operation when the input column or table name does not exist in the database. For example, if a column name is used in a particular function and the column name is invalid, the database management system will sort the results by the first column of the table. Only the table and column names in our advanced API were examined, as GitHub analysis showed that 96% of concatenated IDs were table and column names. In all experiments, the new setColumnName feature surpassed the implementation of dynamic whitelisting. In two experiments, the implementation of a static whitelist slightly exceeded the name function of the new set of columns. Although this special approach has little performance advantage, whitelisting approaches can add non-trivial complexity to program code and lead to erroneous results. The new setColumnName feature has successfully prevented all these attacks. Filling placeholders with column names is practical and effective compared to existing special approaches, does not create additional costs compared to the existing functions of the trained operator, and is effective against SQL identifier injection attack.

APA, Harvard, Vancouver, ISO, and other styles

Santos, Natalia G. P., Deyber A. V. Medina, and Fernando M. Lanças. "Development of Wall-Coated Open Tubular Columns and Their Application to Nano Liquid Chromatography Coupled to Tandem Mass Spectrometry." Molecules 28, no. 13 (2023): 5103. http://dx.doi.org/10.3390/molecules28135103.

Full text

Abstract:

This work presents a study on the application of wall open tubular column (WCOT) in liquid chromatography coupled with tandem mass spectrometry. Each process step reports the column preparation method in detail, subdivided into column pretreatment, silanization, stationary phase coating, and immobilization. Then, an evaluation of the parameters that can affect the efficiency of these columns was made. Atrazine, clomazone, and metolachlor were used as probes during this step. Factors such as stationary phase composition, length, internal diameter, stationary phase mass employed, and injection volume were investigated. In addition, with the help of Knox and Poppe graphs, the columns’ performance was evaluated to determine the optimal flow rate and the speed-efficiency relationship, respectively. Based on the results, the best configurations for the WCOT column application to the LC system were defined: length—8 m; inner diameter—25 μm; mass of OV-210—2.5% m/v; and, injection volume—100 nL. Finally, the optimized WCOT column developed in this work was coupled with a commercially-packed trapping column in the nano liquid chromatography system (nanoLC). In this configuration, more significant results were obtained regarding separation resolution, with Rs = 5.9 achieved for the most retained pair of analytes (clomazone and metolachlor).

APA, Harvard, Vancouver, ISO, and other styles

Hagman, Gunnar, and Johan Roeraade. "Automated at-column injection into narrow bore capillary GC columns." Journal of High Resolution Chromatography 14, no. 10 (1991): 686–88. http://dx.doi.org/10.1002/jhrc.1240141010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Penton, Z. "Gas-chromatographic determination of ethanol in blood with 0.53-mm fused-silica open tubular columns." Clinical Chemistry 33, no. 11 (1987): 2094–95. http://dx.doi.org/10.1093/clinchem/33.11.2094.

Full text

Abstract:

Abstract Several 0.53 mm (i.d.) fused-silica open tubular columns were evaluated for the gas-chromatographic determination of ethanol and other volatiles in blood by both headspace and liquid injection. These columns offer the advantages of fused-silica technology without requiring expensive modification of the instrument for capillary. Methyl silicone columns of various lengths and film thicknesses were examined and also a polyethylene glycol column. The merits of each column are discussed and relative retention times are given.

APA, Harvard, Vancouver, ISO, and other styles

Alkhateeb, Fadi L., Taylor C. Hayward, and Kevin B. Thurbide. "A novel ultrashort capillary gas chromatography method using on-column injection and detection." Canadian Journal of Chemistry 94, no. 4 (2016): 259–64. http://dx.doi.org/10.1139/cjc-2015-0068.

Full text

Abstract:

A novel method for ultrashort capillary column gas chromatography (GC) analysis is introduced, which employs on-column injection and detection and rapid temperature programming. Using 10–20 cm long capillary columns, results showed that the method provides efficient and very rapid separations for relatively simple mixtures. Moreover, the on-column aspect of the method used here is demonstrated to avoid the extra column analyte degradation that can occur in traditional approaches to such separations. As a result, the developed method allows for the first time the GC analysis of some very large and (or) highly thermally labile analytes, such as polypeptides and drug molecules that are normally prone to decomposition. As an application, this method is further used to monitor pharmaceutical degradant formation as a function of temperature and was found to provide similar results to those obtained from conventional high-performance liquid chromatography analysis. Overall, the findings indicate that this ultrashort GC column approach could be useful in these areas and potentially others, where relatively simple GC analysis and universal flame ionization detection is desirable.

APA, Harvard, Vancouver, ISO, and other styles

Evans, R. Douglas, Andrei Izmer, Karima Benkhedda, Andrew Toms, Angelo Fernando, and Wei Wang. "Continuous online determination of 226Ra in liquid effluents using automated column chromatography-ICP-MS." Canadian Journal of Chemistry 93, no. 11 (2015): 1226–31. http://dx.doi.org/10.1139/cjc-2015-0247.

Full text

Abstract:

A measurement system capable of continuous on-line matrix removal, pre-concentration and analysis of 226Ra using pre-packed columns coupled to a flow injection system and an ICP-MS was developed. Full instrumental control of both the ICP-MS and the flow injection system provided automatic integration of the transient signals. The flow injection system was programmed to control column conditioning, sample loading, column rinsing, analyte elution and column cleaning operations employing appropriate solutions. The application of this system to the 226Ra analysis of an industrial liquid effluent was demonstrated. Using this particular instrument together with pre-concentration and matrix removal procedures, a limit of detection of 5.4 fg L−1 (2 mBq L−1) and a method detection limit of 16.2 fg L−1 (6 mBq L−1) were achieved for the measurement of 226Ra using a 25 mL sample volume. Total time for sample handling and analysis is approximately 10 minutes. The concentration of 226Ra in a discharged effluent sample was 0.73 pg L−1 (27 mBq L−1), which is in good agreement with the value of 0.81 pg L−1 (30 mBq L−1) measured using conventional alpha counting techniques.

APA, Harvard, Vancouver, ISO, and other styles

Suzuki, Toshesari, Kumiko Yaguchi, Kazuo Ohnishi, and Tatsunori Yamagishi. "Gas Chromatographic Detection of Tris(2-chloroethyl) and Tris(2-butoxyethyl)phosphate in Groundwater by Large-Sample-Volume Injection." Journal of AOAC INTERNATIONAL 77, no. 6 (1994): 1647–50. http://dx.doi.org/10.1093/jaoac/77.6.1647.

Full text

Abstract:

Abstract A capillary gas chromatograph equipped with a flame photometric detector (GC–FPD) for splitless injection of large sample volume was developed. The GC–FPD effectively diverted dichloromethane from the analytical column through a solvent diversion column and quantitatively retained tri(2-chloroethyl) phosphate (TCEP) and tris(2-butoxyethyl)- phosphate (TBXP) on a cold-trap column in front of the analytical column. The optimum conditions for 100 uL injections of TCEP and TBXP in dichloromethane at concentrations from 1 to 100 ng/mL were investigated. With the GC–FPD, relative standard deviations of the peak area and the retention time of the triesters injected at 10 ng/mL were less than 7.0 and 0.05%, respectively. These results were similar to those from normal splitless injection of 1 μL at 1 μg/mL in dichloromethane. A screening method for TCEP and TBXP in groundwater combined with liquid–liquid extraction with dichloromethane permitted detection at low nanogram-per-liter levels. Recoveries of TCEP and TBXP in 500 mL of groundwater were greater than 77.2 and 81.4%, respectively, each at fortified level of 10ng/L.

APA, Harvard, Vancouver, ISO, and other styles

Jorge, Luiz Mario de Matos, Patrícia Aparecida Polli, Douglas Junior Nicolin, Regina Maria Matos Jorge, Paulo Roberto Paraíso, and Rubens Maciel Filho. "SIMULATION AND ANALYSIS OF AN INDUSTRIAL COLUMN SYSTEM OF BIOETHANOL DISTILLATION HEATED BY VAPOR DIRECT INJECTION." Engevista 17, no. 2 (2015): 254. http://dx.doi.org/10.22409/engevista.v17i2.657.

Full text

Abstract:

Most commercial process simulators have its origin at the petrochemical industry and their use in other sectors depends on testing. In this context a model of an industrial column system of bioethanol distillation heated by direct injection of vapor was developed and implemented using the simulator Aspen HYSYS, which was compared with experimental data obtained in the industrial plant. The system basically consists of four columns heated by direct vapor injection and the model of the system was developed using this approach together with the simulation blocks for columns heated by reboilers available on Aspen HYSYS. For such a task it was admitted a null termal load for the reboiler and a direct vapor stream was added in the side of the column. Overall deviations between simulated values and those measured in the distillery were 2.3 % for temperatures, 12.95 % for concentrations, and 1.07 % for bioethanol production in the industrial distillation system (IDS). The low values of the deviations obtained when comparing the data of the real process with simulated data indicate that IDS is well sized and the model implemented as well as the process simulator adopted can be used in the sugar-ethanol industry with distillation columns heated by direct injection of vapor.

APA, Harvard, Vancouver, ISO, and other styles

Li, Yeou-Fong, and Yi-Ying Sung. "Seismic repair and rehabilitation of a shear-failure damaged circular bridge column using carbon fiber reinforced plastic jacketing." Canadian Journal of Civil Engineering 30, no. 5 (2003): 819–29. http://dx.doi.org/10.1139/l03-042.

Full text

Abstract:

In this paper, the analytical and experimental results of tests on a benchmark and a damaged circular bridge column are presented. The benchmark column is a 40% scale reinforced concrete circular bridge column damaged as a result of shear failure during a cyclic-loading test; the benchmark column was then repaired by epoxy and non-shrinkage mortar and rehabilitated by carbon fiber reinforced plastic (CFRP) after the cyclic-loading test. The benchmark bridge column is tested under a cyclic-loading test with constant axial load. The result shows that the column suffered shear failure at low displacement ductility. Non-shrinkage mortar with high-pressure epoxy injection was used to repair the damaged bridge column, and then three-layer CFRP was used to rehabilitate the shear strength of the bridge column. The test result shows that the repaired and rehabilitated column develops significantly improved hys ter etic responses at high displacement ductility. The analytical lateral force displacement relationship of the bridge columns can accurately predict the experimental result, especially in the nonlinear region.Key words: carbon fiber reinforced plastic, repair and rehabilitation, bridge column.

APA, Harvard, Vancouver, ISO, and other styles

Gharries, Helen. "Clinical anatomy of the spine for pain interventionist." Journal of Anesthesia and Critical Care: Open access 10, no. 4 (2018): 140–45. http://dx.doi.org/10.15406/jaccoa.2018.10.00378.

Full text

Abstract:

Pain interventionist emphasizes particular attention to the spinal anatomy. Spine pain generators differ from intervertebral disc to facet joint or ligaments. Injection at these critical structures requires a complete visualization of anatomical location. Spinal cord injury or intravascular injections are the serious complications of spine pain intervention. Understanding the neurovascular anatomy of the spinal column prevents misfortune injection and its unwanted complications. The purpose of this study is to review spine anatomy and responsible pain generators and to verify the importance of anatomy in preventing pain injections complication.

APA, Harvard, Vancouver, ISO, and other styles

Fujinaga, Takashi, and Yuping Sun. "Structural Performance of Damaged Open-Web Type SRC Beam-Columns after Retrofitting." Sustainability 12, no. 4 (2020): 1381. http://dx.doi.org/10.3390/su12041381.

Full text

Abstract:

The structural performance of damaged open-web type of steel encased reinforced concrete (SRC) beam-columns after retrofitting was experimentally investigated. The experimental parameters were the open-web type of the encased steel and the maximum tip displacement of the columns during the initial loading. First, each column was cyclically loaded to the targeted displacement. Subsequently, the test columns were retrofitted and reloaded. The damaged portions of each column were retrofitted with the polymer cement mortar, and the epoxy resin was injected into the cracks. The experimental results indicated that the measured stiffness of the retrofitted columns was lower than the initial ones, while the displacements experienced in each column were different. The lower stiffness might be attributed to deterioration of the concrete rigidity, low rigidity of the resin and imperfect injection of the resin. Numerical analyses were also conducted to evaluate the retrofitted column behavior. The effect of the strain hysteresis of concrete at the first loading was considered for the behavior at the second loading. The analytical results predicted the experimental behaviors fairly well, which implies the validity of the analytical methods presented in this paper for evaluating the structural performance of the retrofitted SRC columns.

APA, Harvard, Vancouver, ISO, and other styles

Porsch, B., J. Voslář, J. Rosol, and V. Kubánek. "Preparative high-performance liquid chromatographic columns with an intra-column injection system." Journal of Chromatography A 520 (November 1990): 295–305. http://dx.doi.org/10.1016/0021-9673(90)85113-a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Ariny Demong, Andrew Ragai Rigit, and Khairuddin Sanaullah. "Effect of Swirl Gas Injection on Bubble Characteristics in a Bubble Column." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 102, no. 2 (2023): 155–65. http://dx.doi.org/10.37934/arfmts.102.2.155165.

Full text

Abstract:

Swirling gas injection is a well-known technique to improve mass transfer in bubble columns. It can be used to create small bubbles with a high surface area-to-volume ratio, which is beneficial for mass transfer. Swirl gas injection can also be used to create a more uniform bubble size distribution and improve the mixing of gas and liquid in the column. This study aims to determine the impact of swirl gas injection on bubble properties, including bubble shape, size, and velocity. A bubble detection approach has been developed for quick and precise determination of bubble size distributions in gas-liquid systems. Advanced digital image processing, including edge detection and bubble edge recognition, is used in this method. The experiment is conducted in a bubble column at a height of 57 cm and 61 cm. The column had a ring sparger and was made of Plexiglas. Tap water was used as the liquid, while air from an air compressor was utilized as the gas phase. The shape, size, population, and velocity of the bubble are measured using a high-speed digital camera. According to this study, the average bubble size reduced as the impeller speed increased, while the population of bubbles increased when the sparger rotation speed increased from 30 to 150 rpm.

APA, Harvard, Vancouver, ISO, and other styles

Korytár, Peter, Eva Matisová, Henrieta Lefflerová, and Jaroslav Slobodník. "Large Volume Injection in Fast Gas Chromatography with On-Column Injector." Journal of High Resolution Chromatography 23, no. 2 (2000): 149–55. http://dx.doi.org/10.1002/(sici)1521-4168(20000201)23:2<149::aid-jhrc149>3.0.co;2-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Cinar, Muhammet. "Investigation of Mechanical and Physical Features of Cementitious Jet Grout Applications for Various Soil Types." Buildings 13, no. 11 (2023): 2833. http://dx.doi.org/10.3390/buildings13112833.

Full text

Abstract:

The cementitious jet grout method (CJG) is one of the most preferred methods for the ground reinforcement of building foundations. As a result of the soil improvement made with the CJG, it was observed that there was a decrease in settlement, permeability, and liquefaction potential and an increase in the bearing capacity. In this study, columns with different grouting pressures (400, 450, and 500 bar) and water/cement ratios of 0.75, 1.00, and 1.25 were produced on several soil types (sand, clay, and alluvial soil) that have high liquefaction, settlement potential, and low bearing capacity. CJG columns were kept for 28 days after completion and then removed from the soil, and diameter measurements were made and significant differences were observed according to pressure and w/c ratios. Three samples were taken in CJG columns extracted from the ground. Laboratory tests were conducted to determine the physical (water absorption rate, density, and porosity) and mechanical (UCS and UPV) properties of CJG column samples. The highlighting of this paper is to build full-scale CJG columns in sandy soil, clay soil, and alluvial soil, increase the geotechnical engineering properties, and investigate the strength development, and diameter under different w/c ratios and different injection pressures. The strength of CJG columns in sandy soils was found between 36 and 15 MPa, in clay soils between 15 and 4 MPa and in alluvial soils between 32 and 15 MPa. Moreover, it was observed that there was a significant increase in the diameters with the increase in the injection pressure and a decrease in the compressive strengths. When the CJG column diameters were compared with constant injection pressure and increasing w/c ratios, the maximum increase was found to be 13% for sandy soils, 10% for clayey soils, and 14% for alluvial soils. The column diameters were 37% larger for sandy soils than clayey soils and 26% larger than alluvial soils at the same w/c ratio and constant injection pressure. In conclusion, since the results found in this study were made on a real scale in the field and for three different soil conditions, the results can be used directly in future engineering applications.

APA, Harvard, Vancouver, ISO, and other styles

Yang, Defeng, Guobin Xu, and Yu Duan. "Effect of Particle Size on Mechanical Property of Bio-Treated Sand Foundation." Applied Sciences 10, no. 22 (2020): 8294. http://dx.doi.org/10.3390/app10228294.

Full text

Abstract:

In the field of geotechnical engineering, microbially induced calcium precipitation technology is feasible and sustainable alternative to improve the engineering characteristics of sand foundation under different geological conditions for a long time. However, it is unclear how the effects of different sand particle sizes on the engineering characteristics of bio-treated sand column. The method of intermittent injection in batches was used to develop a series of bio-treated sand columns. The results showed that the mechanical properties of the bio-treated column improved by increasing the particle size. Low concentration of bacterial suspension and cementation reagent leads to the increase of calcium carbonate and unconfined compressive strength. Additionally, the total injection times increased, thus risking time cost. Furthermore, the increase of sand particle size was beneficial to the uniformity of the spatial distribution of calcium carbonate in the bio-treated column. The coefficient of variation was reduced by up to 52.0%. Scanning electron microscopy results confirmed that the size and uniformity of calcite crystals on the surface of sand particles were related to the concentration of cementation solution.

APA, Harvard, Vancouver, ISO, and other styles

Schmid, Rainer, and Christian Wolf. "Construction of a new “closed on-column” injector for hot “on-column” injection in capillary gas chromatography." Fresenius' Zeitschrift für analytische Chemie 324, no. 3-4 (1986): 315–16. http://dx.doi.org/10.1007/bf00487956.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Roeraade, J. "At-column injection: An improved method for accurate sample transfer to capillary columns." Journal of High Resolution Chromatography 8, no. 11 (1985): 801–2. http://dx.doi.org/10.1002/jhrc.1240081116.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Ghazali, Nurul Aimi, T. A. T. Mohd, N. Alias, et al. "Gas Lift Optimization of an Oil Field in Malaysia." Advanced Materials Research 974 (June 2014): 367–72. http://dx.doi.org/10.4028/www.scientific.net/amr.974.367.

Full text

Abstract:

Gas lift is an artificial lift method which is commonly used in offshore operation with sufficient gas sources as it consumes minimum space on the platform. Gas lift operates by injecting a high pressure gas down through the tubing casing annulus of a well and the injected gas enters the tubing through a gas lift valve installed on the tubing. Gas lift increases production by two means, density reduction of oil column inside the tubing so that the flowing bottom-hole pressure which is affected by the hydrostatic pressure of the fluid column is reduced and by providing external energy to the oil as the gas expends.Reducing the bottom-hole pressure will improve the drawdown of the well. A production well is modelled by using a production modelling program, Integrated Production Modeling (IPM) Prosper to analyze the production performance at various conditions. A base case model is developed from the production data of an actual oil field to simulate the performance of the actual well without gas lift system. Later, the gas lift is added to the model and the performance was compared with the base case model. The gas parameter was also studied to determine the optimum injection gas condition for maximum oil production. The gas injected at 1490m can be achieved by injecting the gas with 1200 psi, l300 psi or 1400 psi. However, the optimum gas injection pressure was determined to be at 1400 psi as the design shows that the required unloading stage is the least. The optimum gas injection rate was determined at 5 MMscf/d with the estimated net revenue is the highest. For injection gas gravity, the lighter gas was determined to be the optimum selection since it gives significant reduction of FBHP (Flowing Bottom Hole Pressure) with less hydrostatic pressure inside the tubing column.

APA, Harvard, Vancouver, ISO, and other styles

Schweitzer, Jeffrey S., Bin Song, Pierre R. Leblanc, Melissa Feitosa, Bob S. Carter, and Kwang-Soo Kim. "Columnar Injection for Intracerebral Cell Therapy." Operative Neurosurgery 18, no. 3 (2019): 321–28. http://dx.doi.org/10.1093/ons/opz143.

Full text

Abstract:

Abstract BACKGROUND Surgical implantation of cellular grafts into the brain is of increasing importance, as stem cell-based therapies for Parkinson and other diseases continue to develop. The effect of grafting technique on development and survival of the graft has received less attention. Rate and method of graft delivery may impact the cell viability and success of these therapies. Understanding the final location of the graft with respect to the intended target location is also critical. OBJECTIVE To describe a “columnar injection” technique designed to reduce damage to host tissue and result in a column of graft material with greater surface area to volume ratio than traditional injection techniques. METHODS Using a clinically relevant model system of human embryonic stem cell-derived dopaminergic progenitors injected into athymic rat host brain, we describe a novel device that allows separate control of syringe barrel and plunger, permitting precise deposition of the contents into the cannula tract during withdrawal. Controls consist of contralateral injection using traditional techniques. Graft histology was examined at graft maturity. RESULTS Bolus grafts were centered on the injection tract but were largely proximal to the “target” location. These grafts displayed a conspicuous peripheral distribution of cells, particularly of mature dopaminergic neurons. In contrast, column injections remained centered at the intended target, contained more evenly distributed cells, and had significantly more mature dopaminergic neurons. CONCLUSION We suggest that this columnar injection technique may allow better engraftment and development of intracerebral grafts, enhancing outcomes of cell therapy, compared to fixed-point injection techniques.

APA, Harvard, Vancouver, ISO, and other styles

Akchurin, Ruslan Z., Filyus F. Davletshin, Denis F. Islamov, Rim A. Valiullin, and Ayrat Sh Ramazanov. "Features of the thermal field during fluid injection into the well during induction heating of the casing." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 9, no. 4 (2023): 44–58. http://dx.doi.org/10.21684/2411-7978-2023-9-4-44-58.

Full text

Abstract:

Pumping water into productive formations is one of the most common methods of oil field development. The effectiveness of reservoir flooding technology largely depends on the compliance of the design and actual volumes of water injection. Due to the violation of the tightness of the cement ring, fluid flows occur in the column space, which cause non-project withdrawal of the injected liquid into non-perforated layers. Identification and prompt elimination of backwater flows during injection of liquid into injection wells is one of the important tasks of efficient and environmentally friendly development of oil fields. The paper considers the use of induction heating of the casing string to determine the bottom-up backflow when pumping liquid into the well. The research is based on numerical modeling in the Ansys Fluent engineering package. Scenarios of absence and presence of overflow during injection of liquid into the well are simulated. It is shown that in a well without overflow, the temperature field disturbance propagates from the heated section of the column mainly radially into cement and rocks, in a well with overflow, the thermal disturbance from the heating section also propagates vertically in the direction of the overflow, and at a distance of up to 1 m above the heating section, temperature disturbances in the column body and the column space reach 2…3 K. It was found that the signs of overflow are also a decrease in the degree of heating of the casing string and an increased dynamics of cooling of the column over time compared with the absence of the column movement of the liquid. The results obtained serve as a theoretical justification for the fundamental informativeness of the active thermometry method in the diagnosis of backwater flows in injection wells.

APA, Harvard, Vancouver, ISO, and other styles

Kuznetsov, V. G., and O. A. Makarov. "PRESSURE CONTROL SYSTEM AT CEMENTATION OF WELLS." Oil and Gas Studies, no. 1 (March 1, 2017): 62–67. http://dx.doi.org/10.31660/0445-0108-2017-1-62-67.

Full text

Abstract:

At cementing of casing of oil and gas wells during the process of injecting of cement slurry in the casing column the slurry can move with a higher speed than it’s linear injection speed. A break of continuity of fluid flow occurs, what can lead to poor quality isolation of producing formations and shorten the effective life of the well. We need to find some technical solution to stabilize the linear velocity of the cement slurry in the column. This task can be resolved with an automated control system.

APA, Harvard, Vancouver, ISO, and other styles

Arrendale, R. F., J. T. Stewart, and R. M. Martin. "Effects of the pre-column in automated on-column injection capillary gas chromatography." Journal of Chromatography A 518 (January 1990): 307–18. http://dx.doi.org/10.1016/s0021-9673(01)93192-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Syamsuri, Syamsuri, Wulandari Mirzayanti Yustia, Lillahulhaq Zain, and Bagus Hidayat Achmad. "Implementation of packed column for biogas purification as fuel for motorcycle injection systems for performance improvement." Eastern-European Journal of Enterprise Technologies 4, no. 1 (112) (2021): 86–93. https://doi.org/10.15587/1729-4061.2021.239027.

Full text

Abstract:

The use of gasoline for primary energy consumption can reduce crude oil, contained in the earth. The development of alternative fuels such as biogas and biofuel is very critical to overcoming this problem. Biogas requires purification to remove some contaminant particles that interfere with the combustion process. The packed column is generally applied to absorb and separate gas and liquid mixture. It is more efficient due to the liquid flows down the column of steam naturally without the supply of energy from outside the system. This study focuses on determining the effect of the packed column biogas purification process. Biogas is applied as an alternative fuel in spark-ignition engines (SIE). The test is carried out using a chassis dynamometer to obtain power and torque data. The use of the packed column for biogas fuel purification can produce higher performance compared to unrefined biogas. The unrefined biogas still contains impurities that can interfere with the combustion process. This condition is proven by measuring the power and torque of the vehicle on the chassis dynamometer, where the filtered biogas produces higher power and torque. Tests were carried out both using the packed column and without the packed column. Variations from speed to torque, to power, to SFC and BMEP are considered. In this study, validation is in good agreement with previous studies. Overall, the results show that the average error between using the packed column and without the packed column for torque, power, SFC and BMEP is increased by approximately 7 %. Purification of biogas using the packed column using Ca(OH)<sub>2</sub> can bind CO<sub>2</sub> and obtain pure methane gas with a higher heating value. In conclusion, the packed column for biogas purification as fuel for motorcycle injection systems can be applied

APA, Harvard, Vancouver, ISO, and other styles

Nguyen, Thanh-Tuan, Do-Gun Kim, and Seok-Oh Ko. "Degradation of Oxytetracycline in Saturated Porous Media by In Situ Chemical Oxidation Using Oxygen-Doped Graphitic Carbon Nitride and Peroxymonosulfate: Laboratory-Scale Column Experiments." Water 16, no. 16 (2024): 2355. http://dx.doi.org/10.3390/w16162355.

Full text

Abstract:

Oxytetracycline (OTC) is frequently detected in groundwater and soil, posing substantial risks to the subsurface environment via persistence, phytotoxicity, changing bacterial communities, and antibiotic resistance. In situ chemical oxidation (ISCO) is one of the best alternatives for removing OTC from groundwater. However, its feasibility has rarely been investigated using columns for which optimal conditions can be obtained for practical applications. Thus, a system consisting of oxygen-doped graphitic carbon nitride (OgCN) and peroxymonosulfate (PMS) (OgCN/PMS) was tested for OTC removal using continuous-flow experiments with columns packed with sand and glass beads (GBs). The sand column exhibited better adsorption and degradation of OTC than the GB column in pulse injection experiments, regardless of whether OgCN was packed. Additional experiments were performed using a column saturated with the OTC solution and another filled with deionized water to simulate ISCO, using GB as the medium, to evaluate the net OTC removal by catalytic oxidation, excluding adsorption. Performance improved with increased OgCN packing, PMS dosage, retention time, and pH. Anions slightly affected the performance due to scavenging and propagation of radicals. These findings indicate the high potential of OgCN/PMS for ISCO and the usefulness of column experiments in field applications.

APA, Harvard, Vancouver, ISO, and other styles

Engelhardt, H., R. Klinkner, and G. Schöndorf. "Post-column reaction detection and flow injection analysis." Journal of Chromatography A 535 (December 1990): 41–53. http://dx.doi.org/10.1016/s0021-9673(01)88934-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Janák, Karel, Anders Colmsjö, and Conny Östman. "Increased on-column injection temperature for gas chromatography." Journal of High Resolution Chromatography 18, no. 2 (1995): 117–20. http://dx.doi.org/10.1002/jhrc.1240180211.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Fehringer, Norbert V., and Stephen M. Walters. "Evaluation of Capillary Gas Chromatography for Pesticide and Industrial Chemical Residue Analysis. II. Comparison of Quantitative Results Obtained on Capillary and Packed Columns." Journal of AOAC INTERNATIONAL 69, no. 1 (1986): 90–93. http://dx.doi.org/10.1093/jaoac/69.1.90.

Full text

Abstract:

Abstract Results of pesticide and industrial chemical residue determinations, using both capillary and packed column gas chromatography (GC), in 3 Food and Drug Administration (FDA) laboratories have been compiled and compared. Samples consisted of food products collected for routine residue screening by the respective laboratories. Extracts were prepared by conventional multiresidue methodology. Capillary column systems and operating conditions were selected at the discretion of each laboratory and were therefore variable, although split/splitless injectors in the split mode were used with prescribed precautions in all cases. Packed column systems were operated as specified in the FDA Pesticide Analytical Manual (PAM). Overall correlation between the 2 systems, expressed as the average ratio of packed column result to capillary column result, was 0.99 for 120 determinations in 41 samples. The higher resolving power of the capillary systems allowed quantitation of several residues that were incompletely separated and therefore unquantifiable using the packed columns. Capillary column GC with the split injection technique, used with appropriate precautions, was found to be both reliable and advantageous for regulatory determination of pesticide and industrial chemical residues in foods and feeds.

APA, Harvard, Vancouver, ISO, and other styles

Berg, Jonathan D., and Brendan M. Buckley. "Rapid Measurement of Anticonvulsant Drug Concentrations in the Out-Patient Clinic, Using HPLC with Direct Injection of Plasma." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 24, no. 5 (1987): 488–93. http://dx.doi.org/10.1177/000456328702400511.

Full text

Abstract:

A manual column-switching technique is described for the measurement of phenytoin, phenobarbitone, carbamazepine, and carbamazepine 10,11-epoxide. The analytical system is designed to be portable for use at the out-patient clinic and comprises an isocratic pump, UV detector and injection valve, together with a preparation column. Diluted plasma or serum is injected, without pre-extraction, onto a preparation column which replaces the sample loop on the injection valve. After washing unwanted material to waste, the preparation column is switched in-line with the analytical column, where separation of analytes occurs. The precision, accuracy and carryover of this extra-laboratory system are comparable with those obtained with laboratory-based immunoassay systems. Operation of the system allows the reporting of results within 5 min of sample injection and requires no specialist skills. The technique should be of particular interest to district general hospital laboratories where workload does not justify the cost of an automated HPLC system as the total capital cost is comparable to that of a portable glucose analyser. In contrast to immunoassay systems consumable costs are minimal. The equipment is easy to transport and may be used in the out-patient department to provide an analytical service similar to that provided for the determination of prothrombin time at the anticoagulant clinic.

APA, Harvard, Vancouver, ISO, and other styles

Burakham, R., and K. Grudpan. "Flow Injection and Sequential Injection On-line Pre-column Derivatization for Liquid Chromatography." Journal of Chromatographic Science 47, no. 8 (2009): 631–35. http://dx.doi.org/10.1093/chromsci/47.8.631.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Hinshaw, J. V., and W. Seferovic. "Programmed-temperture split-splitless injection of triglycerides: Comparison to cold on-column injection." Journal of High Resolution Chromatography 9, no. 2 (1986): 69–72. http://dx.doi.org/10.1002/jhrc.1240090203.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Kodama, K., K. Yamanaka, T. Nakata, and M. Aoyama. "Liquid-chromatographic assay of urinary vanillylmandelic acid and homovanillic acid, with clean-up by on-column injection of acetonitrile or methanol." Clinical Chemistry 32, no. 10 (1986): 1944–47. http://dx.doi.org/10.1093/clinchem/32.10.1944.

Full text

Abstract:

Abstract To separately measure vanillylmandelic acid (VMA) and homovanillic acid (HVA) in urine, the sample is diluted 10-fold with 50 mmol/L phosphoric acid, then exactly 5 microL is injected directly onto a 50 X 4.6 mm column of Nucleosil 3C18. Samples can be injected at 5-min intervals because all peaks after these compounds of interest are washed away. VMA is eluted from the column after 2.8 min with 50 mmol/L phosphate buffer, pH 2.2, and measured by electrochemical detection. All peaks eluting after VMA are washed away together, by injection of 50 microL of acetonitrile onto the column. HVA is eluted from the column after 3.3 min with a 100/10 (by vol) mixture of the phosphate buffer and acetonitrile. All later-eluting peaks are washed away together, by injection of 50 microL of methanol onto the column. Analytical recoveries of VMA and HVA were 98.5% and 100.6%, respectively; the CVs for various concentrations of either in urine were about 3%.

APA, Harvard, Vancouver, ISO, and other styles

Wang, Cong. "Integrated technology for layered sand control and layered water injection." Journal of Physics: Conference Series 2683, no. 1 (2024): 012044. http://dx.doi.org/10.1088/1742-6596/2683/1/012044.

Full text

Abstract:

Abstract In order to solve the problem of water injection string failure caused by pipe creep and sand production in layered water injection wells, an integrated technology of layered sand control and layered water injection has been developed. A suspended large-radiuslayered mechanical sand control pipe column has been designed, providing sufficient design and usage space for the layered water injection pipe column. Developing a new type of anti-creep sealed packer can effectively improve the anti-creep performance of the water injection string and extend the validity period of the string. This technology integrates and optimizes layered water injection and sand control technology, large channel backwashing technology, integrated testing and allocation technology, and anti-creep technology of the pipe string. While effectively solving sand production in offshore water injection wells, it extends the service life of the water injection pipe string and reduces operating costs. Since 2018, this technology has been implemented in over 200 wells in Chengdao Oilfield, with a maximum of 6 layers for prevention and injection, a maximum well inclination of 48.8°, and a construction success rate of over 90%. It has achieved very good development results and economic benefits.

APA, Harvard, Vancouver, ISO, and other styles

Petrov, Panayot, Simon Cowen, and Heidi Goenaga-Infante. "On-column internal standardisation as an alternative calibration strategy for speciation analysis: feasibility demonstration through analysis of inorganic As in rice." Analytical Methods 13, no. 33 (2021): 3641–48. http://dx.doi.org/10.1039/d1ay00699a.

Full text

Abstract:

On-column species-specific internal calibration, based on the injection of internal standard, which is the same as the analyte species, compensates for on-column losses, signal drift and others, and provides accurate measurements with low uncertainty.

APA, Harvard, Vancouver, ISO, and other styles

Chen, Meilan, Jiasheng Yu, Mingli Ye, and Weiqiang Guo. "Analysis of Ammonium in Seawater by Ion Chromatography With Single-Pump Column Switching." Marine Technology Society Journal 51, no. 3 (2017): 43–47. http://dx.doi.org/10.4031/mtsj.51.3.5.

Full text

Abstract:

AbstractAn ion chromatograph single-pump column-switching system was developed for the determination of ammonium in high salt matrices. The simple system included a pump, a suppressor, two valves, two columns, a single eluent, and a conductivity detector. Using this method, both online collection and matrix elimination were achieved. Ammonium was eluted from the acceptor loop to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r = 0.9997) in the range of 0.05‐2.0 mg/L and satisfactory repeatability (RSD < 4%, n = 6). The limit of detection was 4 μg/L (S/N = 3) with 25 μl injection. The utilization of the method was demonstrated by the analysis of seawater, with satisfactory spiked recoveries of ammonium between 98.8% and 108.7%. The result showed that the single-pump column-switching system was convenient and practical for the determination of low-level ammonium in high-salinity samples.

APA, Harvard, Vancouver, ISO, and other styles

Maris, Christophe, Alain Laplanche, Jean Morvan, and Marianne Bloquel. "Development of a Packed Precolumn for Capillary Gas Chromatographic Analysis of Amines in Acidic Aqueous Solution." Water Science and Technology 40, no. 6 (1999): 141–48. http://dx.doi.org/10.2166/wst.1999.0283.

Full text

Abstract:

This paper describes an optimization of the analysis of amines in aqueous solution. Direct injection of the acidic sample (HCl 0.12 N) is performed by the coupling of packed precolumn with a capillary column. The basic support efficiently traps residual vapors of hydrochloric acid and water at the injection time; the capillary chromatographic performance is maintained. The precolumn coupling with PoraPLOT Amines capillary column enables a separation and quantification of the lower volatile aliphatic amines (methylamine, dimethylamine, trimethylamine and ethylamine). The ammonia addition to the solution (200 ppm NH3) reduces amine adsorption in the column. The analysis repeatability is about 5% for a 50μM amine mixture and 21% for the quantification limit of 0.5 μM with a sensitive and specific nitrogen phosphor detector. The precolumn avoids using split injection (sensitivity increased). Other nitrogen compounds can be analyzed by this system: aromatic amines (aniline) and unsaturated nitrogen heterocycles (pyridine). This new technique increases the chromatographic performances in comparison with usual methods; its automation is possible.

APA, Harvard, Vancouver, ISO, and other styles

Groutsi, F., M. R. J. Mason, P. N. Anderson, et al. "Retrograde viral transduction of cortical pyramidal neurons from the spinal cord." Restorative Neurology and Neuroscience 26, no. 6 (2008): 509–20. https://doi.org/10.3233/rnn-2008-00451.

Full text

Abstract:

Purpose: The primary motor pathway, the corticospinal tract, is a major target for spinal cord regeneration studies. One way of improving the regeneration of corticospinal axons is to introduce regeneration-associated genes into cortical motor neurons using viral vector delivery. Methods: We used an engineered Herpes Simplex virus (HSV1) with the EF1α promoter encoding either LacZ or GFP to transduce cortical neurons through retrograde transport following the injection of vector into adult rat striatum or spinal cord. After three-days to one-month post-injection, sections of brain and spinal cord were viewed with fluorescence microscopy or processed for LacZ histochemistry. Results: Many layer V motor cortical neurons were transduced following striatal injections. These were not corticospinal neurons as they were not fluorogold-labelled following tracer injection into spinal cord. Corticospinal neurons in both hemispheres were, however, transduced following direct vector injections into the dorsal column of spinal cord, yielding 250–400 transduced corticospinal neurons per animal. No non-pyramidal neurons or thalamic neurons were transduced by spinal injections. Conclusions: Therefore, this HSV1.EF1α vector is highly effective for the transduction of corticospinal neurons without direct injection into the brain and could be used to introduce regeneration-relevant genes into these neurons with the aim of regenerating the corticospinal tract.

APA, Harvard, Vancouver, ISO, and other styles

Wang, Lu, and Shuhua Liu. "Mechanism of Sand Cementation with an Efficient Method of Microbial-Induced Calcite Precipitation." Materials 14, no. 19 (2021): 5631. http://dx.doi.org/10.3390/ma14195631.

Full text

Abstract:

This paper presents an efficient method of microbial-induced calcite precipitation (MICP) for cementation of sand particles. First, the influence of initial pH value of the culture medium on the growth of bacteria was discussed. Then, the compressive strength and calcium carbonate content of cemented sand columns with different sand particle sizes were measured to indicate the cementation effectiveness. The microstructure of cemented sand columns as well as the mineral composition and distribution of calcium carbonate were characterised by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The results showed that the urease-producing bacteria S. pasteurii can be cultured at the initial pH values of 7–10, while a higher pH (e.g., 11) would hinder its growth and decrease its urease activity. The injection method of MICP with high standing time can cement sand columns effectively. Small average sand particle size of sand columns and high injection cycles can facilitate the gain of compressive strength, while calcium carbonate content of sand column higher than 8% can promote the increase of compressive strength. XRD results indicate that the fine grains generated on the surface of sand particles are calcite. The distribution of calcite on sand particles’ surface is broad and uniform. First, calcite was precipitated on the surface of sand particles, and then a precipitation layer was formed, which would connect sand particles through its high enough thickness and contribute to the development of compressive strength of the whole sand column.

APA, Harvard, Vancouver, ISO, and other styles

Deng, Weimin, and Randolph M. Beaudry. "Overcoming Gas Sampling Problems: Analysis of Volatiles Using Capillary Column Needles." HortScience 31, no. 4 (1996): 643f—643. http://dx.doi.org/10.21273/hortsci.31.4.643f.

Full text

Abstract:

Sampling factors that could affect gas chromatograph (GC) response for volatile analysis such as syringe pumping time, injection volume, needle length, temperature, and the type of volatile were investigated. Capillary GC column segments (steel and glass) were installed in gas-tight syringes and used as needles for volatile analysis. Standard stainless-steel needles were also used. Hexylacetate, ethyl-2-methylbutyrate, 6-methyl-5-hepten-2-one, and butanol standard were measured. The number of pumps required to maximize GC response for each needle–volatile combination was determined. Maximal GC response for hexylacetate using standard stainless steel, capillary glass, and capillary steel needles required 10, 20 and 30 pumps, respectively. However, for butanol measurement, the optimal syringe pump number was 5 to 10 for all needle types. The use of a capillary needle resulted in an increase in GC response in the range of 3- to 15-fold relative to a standard stainless steel needle. Injection volume affected GC response in a needle-and volatile-dependent manner. In no case did injection volume vs. GC response extrapolate through origin. The GC response for capillary column needles increased as temperature decreased. Capillary column needles may be useful tools for analysis of volatiles that readily partition into the column coating.

APA, Harvard, Vancouver, ISO, and other styles

Shihabi, Z. K., and R. D. Dyer. "Serum Injection of the HPLC Column for Carbamazepine Assay." Journal of Liquid Chromatography 10, no. 11 (1987): 2383–91. http://dx.doi.org/10.1080/01483918708068919.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Shihabi, Z. K., R. D. Dyer, and J. Scaro. "Serum Injection on the HPLC Column for Pentobarbital Assay." Journal of Liquid Chromatography 10, no. 4 (1987): 663–72. http://dx.doi.org/10.1080/01483918708069017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

SATOH, IKUO, and IKUKO SAKURAI. "Use of a Laccase-Column for Flow-Injection Calorimetry." Annals of the New York Academy of Sciences 864, no. 1 ENZYME ENGINE (1998): 493–96. http://dx.doi.org/10.1111/j.1749-6632.1998.tb10366.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!