Academic literature on the topic 'Escherichia coli O157:H7 Microbiological assay. Immunoassay'

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Journal articles on the topic "Escherichia coli O157:H7 Microbiological assay. Immunoassay"

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DeCory, Thomas R., Richard A. Durst, Scott J. Zimmerman, Linda A. Garringer, Gary Paluca, Heleen H. DeCory, and Richard A. Montagna. "Development of an Immunomagnetic Bead-Immunoliposome Fluorescence Assay for Rapid Detection of Escherichia coli O157:H7 in Aqueous Samples and Comparison of the Assay with a Standard Microbiological Method." Applied and Environmental Microbiology 71, no. 4 (April 2005): 1856–64. http://dx.doi.org/10.1128/aem.71.4.1856-1864.2005.

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ABSTRACT The objective of this study was to develop and optimize a protocol for the rapid detection of Escherichia coli O157:H7 in aqueous samples by a combined immunomagnetic bead-immunoliposome (IMB/IL) fluorescence assay. The protocol consisted of the filtration or centrifugation of 30- to 100-ml samples followed by incubation of the filter membranes or pellet with anti-E. coli O157:H7 immunomagnetic beads in growth medium specific for E. coli O157:H7. The resulting E. coli O157:H7-immunomagnetic bead complexes were isolated by magnetic separation, washed, and incubated with sulforhodamine B-containing immunoliposomes specific for E. coli O157:H7; the final immunomagnetic bead-E. coli O157:H7-immunoliposome complexes were again isolated by magnetic separation, washed, and lysed with a n-octyl-β-d-glucopyranoside to release sulforhodamine B. The final protocol took less than 8 h to complete and had a detection limit of less than 1 CFU of E. coli O157:H7 per ml in various aqueous matrices, including apple juice and cider. To validate the protocol at an independent facility, 100-ml samples of groundwater with and without E. coli O157:H7 (15 CFU) were analyzed by a public health laboratory using the optimized protocol and a standard microbiological method. While the IMB/IL fluorescence assay was able to identify E. coli O157:H7-containing samples with 100% accuracy, the standard microbiological method was unable to distinguish E. coli O157:H7-spiked samples from negative controls without further extensive workup. These results demonstrate the feasibility of using immunomagnetic beads in combination with sulforhodamine B-encapsulating immunoliposomes for the rapid detection of E. coli O157:H7 in aqueous samples.
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BLAIS, BURTON W., RONALD A. BOOTH, LUCILLE PHILLIPPE, SITHIAN PANDIAN, and HIROSHI YAMAZAKI. "Polymacron™ Enzyme Immunoassay System for Detection of Escherichia coli O157 Inoculated into Foods†." Journal of Food Protection 60, no. 2 (February 1, 1997): 98–101. http://dx.doi.org/10.4315/0362-028x-60.2.98.

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A rapid and simple enzyme immunoassay system was developed for detection of the food-borne pathogen Escherichia coli O157. This system is based on the use of anti-E. coli O157 antibody-coated Polymacron™, an inexpensive macroporous polyester fabric, as a high-surface-area immunoadsorbent for the rapid capture and subsequent immunoenzymatic detection of E. coli O157 antigens extracted from test samples by heating at 100°C for 10 min in the presence of sodium cholate. A dot blot format was used which facilitated the assay of multiple samples. The method was specific for all strains tested bearing the O157 and related antigens (e.g., group N Salmonella), giving positive reactions in the assay of pure cultures of 29 E. coli O157:H7 strains, one E. coli O157:H12, one E. coli O157:NM (nonmotile) and one Salmonella urbana strain, but not in the assay of a variety of other gram-negative and gram-positive bacteria. The method permitted the detection of ca. 400 E. coli O157:H7 CFU in a 5-μl spot applied to Polymacron™, and of as few as 0.4 CFU of E. coli O157:147 cells per g inoculated into ground beef samples, which were assayed after overnight enrichment.
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HUANG, SHIU W., and TSUNG C. CHANG. "Specific Identification of Escherichia coli O157 by an Immunostick Method Using Commercially Available Antibodies." Journal of Food Protection 59, no. 6 (June 1, 1996): 670–73. http://dx.doi.org/10.4315/0362-028x-59.6.670.

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A sandwich enzyme-immunoassay performed on plastic sticks was developed to specifically identify Escherichia coli O157. Colonies of test bacteria grown on tryptic soy agar were suspended in phosphate-buffered saline, heated in a 100°C water bath for 15 min, and incubated with the plastic sticks coated with a commercial preparation of anti-E. coli O157 antibodies at 37°C for 1.5 h. After incubation, the same antibodies labeled with peroxidase were used to produce the signal of antigen-antibody reaction. For 35 strains of E. coli O157 (among them 34 were E. coli O157:H7) tested, all produced strong reactions by the immunoassay. For 162 strains of E. coli with somatic antigens other than O157 and 38 strains of other genera tested, only one strain (Salmonella bietri) produced a false-positive reaction. The specificity and sensitivity of the immunostick assay were 100% (35/35) and 99.5% (199/200), respectively. The detection limit of the assay for E. coli O157:H7 (CCRC 15991) was about 105 CFU/ml. The method, which can be carried out within 3 h, is useful for rapid identification of suspect E. coli O157 isolated on selective media.
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FRATAMICO, PINA M., and LORI K. BAGI. "Comparison of Methods for Detection and Isolation of Cold- and Freeze-Stressed Escherichia coli O157:H7 in Raw Ground Beef†." Journal of Food Protection 70, no. 7 (July 1, 2007): 1663–69. http://dx.doi.org/10.4315/0362-028x-70.7.1663.

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A comparison was made of the relative efficiencies of three enrichment media, RapidChek Escherichia coli O157:H7 enrichment broth (REB), R&F broth (RFB), and modified E. coli broth containing novobiocin (mEC+n), and four selective plating media for detection of cold- and freeze-stressed E. coli O157:H7 in raw ground beef. Ground beef (25 g) was inoculated with E. coli O157:H7 at ≤0.5 and ≤2 CFU/g, and samples were then enriched immediately or were stored at 4°C for 72 h or at −20°C for 2 weeks and then enriched. After 8 or 20 h of enrichment, the cultures were plated onto R&F E. coli O157: H7 chromogenic plating medium, cefixime-tellurite sorbitol MacConkey agar, CHROMagar O157, and Rainbow agar O157 and tested using the RapidChek E. coli O157 lateral flow immunoassay and a multiplex PCR assay targeting the E. coli O157: H7 eae, stx1, and stx2 genes. Recovery of E. coli O157:H7 on the four agar media was 4.0 to 7.9 log CFU/ml with the REB enrichment, 1.4 to 7.4 log CFU/ml with RFB, 1.7 to 6.7 log CFU/ml with mEC+n incubated at 42°C, and 1.3 to 3.3 log CFU/ml from mEC+n incubated at 35°C. The percentages of positive ground beef samples containing nonstressed, cold-stressed, and freeze-stressed E. coli O157:H7 as obtained by plating, the immunoassay, and the PCR assay were 97, 88, and 97%, respectively, with REB, 92, 81, and 78%, respectively, with RFB, 97, 58, and 53%, respectively, with mEC+n incubated at 42°C, and 22, 31, and 25%, respectively, with mEC+n incubated at 35°C. Logistic regression analyses of the data indicated significant main effects of treatment, type of medium, enrichment time, inoculum concentration, and detection method. In particular, a positive result was 1.1 times more likely to occur after 20 h of enrichment than after 8 h, 25 times more likely with RFB and REB than with mEC+nat35°C, 3.7 times more likely with an initial inoculum of ≤2.0 CFU/g than with ≤0.5 CFU/g, 2.5 to 3 times more likely using freeze-stressed or nonstressed bacteria than with cold-stressed bacteria, and 2.5 times more likely by plating than by the immunoassay or the PCR assay. REB had better overall performance for enrichment of cold- and freeze-stressed E. coli O157:H7 present in ground beef than did the other media examined.
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AYDIN, MUHSIN, GENE P. D. HERZIG, KWANG CHEOL JEONG, SAMANTHA DUNIGAN, PARTH SHAH, and SOOHYOUN AHN. "Rapid and Sensitive Detection of Escherichia coli O157:H7 in Milk and Ground Beef Using Magnetic Bead–Based Immunoassay Coupled with Tyramide Signal Amplification." Journal of Food Protection 77, no. 1 (January 1, 2014): 100–105. http://dx.doi.org/10.4315/0362-028x.jfp-13-274.

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Escherichia coli O157:H7 is a major foodborne pathogen that has posed serious problems for food safety and public health. Recent outbreaks and recalls associated with various foods contaminated by E. coli O157:H7 clearly indicate its deleterious effect on food safety. A rapid and sensitive detection assay is needed for this harmful organism to prevent foodborne illnesses and control outbreaks in a timely manner. We developed a magnetic bead–based immunoassay for detection of E. coli O157:H7 (the most well-known Shiga toxigenic E. coli strain) with a 96-well microplate as an assay platform. Immunomagnetic separation (IMS) and tyramide signal amplification were coupled to the assay to increase its sensitivity and specificity. This immunoassay was able to detect E. coli O157:H7 in pure culture with a detection limit of 50 CFU/ml in less than 3 h without an enrichment step. The detection limit was decreased 10-fold to 5 CFU/ml with addition of a 3-h enrichment step. When this assay was tested with other nontarget foodborne pathogens and common enteric bacteria, no cross-reactivity was found. When tested with artificially contaminated ground beef and milk samples, the assay sensitivity decreased two- to fivefold, with detection limits of 250 and 100 CFU/ml, respectively, probably because of the food matrix effect. The assay results also were compared with those of a sandwich-type enzyme-linked immunosorbent assay (ELISA) and an ELISA coupled with IMS; the developed assay was 25 times and 4 times more sensitive than the standard ELISA and the IMS-ELISA, respectively. Tyramide signal amplification combined with IMS can improve sensitivity and specificity for detection of E. coli O157:H7. The developed assay could be easily adapted for other foodborne pathogens and will contribute to improved food safety and public health.
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Ingram, David T., Chinta M. Lamichhane, David M. Rollins, Lewis E. Carr, Edward T. Mallinson, and Sam W. Joseph. "Development of a Colony Lift Immunoassay To Facilitate Rapid Detection and Quantification of Escherichia coli O157:H7 from Agar Plates and Filter Monitor Membranes." Clinical Diagnostic Laboratory Immunology 5, no. 4 (July 1, 1998): 567–73. http://dx.doi.org/10.1128/cdli.5.4.567-573.1998.

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ABSTRACT E. coli O157:H7 is a food-borne adulterant that can cause hemorrhagic ulcerative colitis and hemolytic uremic syndrome. Faced with an increasing risk of foods contaminated with E. coli O157:H7, food safety officials are seeking improved methods to detect and isolate E. coli O157:H7 in hazard analysis and critical control point systems in meat- and poultry-processing plants. A colony lift immunoassay was developed to facilitate the positive identification and quantification of E. coli O157:H7 by incorporating a simple colony lift enzyme-linked immunosorbent assay with filter monitors and traditional culture methods. Polyvinylidene difluoride (PVDF) membranes (Millipore, Bedford, Mass.) were prewet with methanol and were used to make replicates of every bacterial colony on agar plates or filter monitor membranes that were then reincubated for 15 to 18 h at 36 ± 1°C, during which the colonies not only remained viable but were reestablished. The membranes were dried, blocked with blocking buffer (Kirkegaard and Perry Laboratories [KPL], Gaithersburg, Md.), and exposed for 7 min to an affinity-purified horseradish peroxidase-labeled goat anti-E. coli O157 antibody (KPL). The membranes were washed, exposed to a 3,3′,5,5′-tetramethylbenzidine membrane substrate (TMB; KPL) or aminoethyl carbazole (AEC; Sigma Chemical Co., St. Louis, Mo.), rinsed in deionized water, and air dried. Colonies of E. coli O157:H7 were identified by either a blue (via TMB) or a red (via AEC) color reaction. The colored spots on the PVDF lift membrane were then matched to their respective parent colonies on the agar plates or filter monitor membranes. The colony lift immunoassay was tested with a wide range of genera in the family Enterobacteriaceae as well as different serotypes within the E. coli genus. The colony lift immunoassay provided a simple, rapid, and accurate method for confirming the presence of E. coli O157:H7 colonies isolated on filter monitors or spread plates by traditional culture methods. An advantage of using the colony lift immunoassay is the ability to test every colony serologically on an agar plate or filter monitor membrane simultaneously for the presence of the E. coli O157 antigen. This colony lift immunoassay has recently been successfully incorporated into a rapid-detection, isolation, and quantification system for E. coli O157:H7, developed in our laboratories for retail meat sampling.
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Feldsine, Philip T., Shannon T. Green, Andrew H. Lienau, and David E. Kerr. "Comparative Validation Study to Demonstrate the Equivalence of a Minor Modification to AOAC Methods 996.09, VIP® for EHEC and 996.10, Assurance EIA® EHEC with the Reference Culture Method for the Detection of Escherichia coli O157:H7 in Beef." Journal of AOAC INTERNATIONAL 88, no. 4 (July 1, 2005): 1193–96. http://dx.doi.org/10.1093/jaoac/88.4.1193.

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Abstract The Visual Immunoprecipitate Assay (VIP®) method for the detection of enterohemorrhagic Escherichia coli O157:H7 (VIP for EHEC) and Assurance® Enzyme Immunoassay (EIA) method for the detection of EHEC (EHEC EIA) are AOAC INTERNATIONAL Official Methods 996.09 and 996.10, respectively. A minor modification to the enrichment medium used in both methods has been developed. This modification, the BioControl modified EHEC medium™ (BioControl mEHEC™) provides a more cost-effective procedure with performance equivalent to that of the cultural method for detection of E. coli O157:H7 in beef.
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CALICCHIA, MELISSA L., E. L. PARKER, S. GAMBREL-LENARZ, and RICHARD R. MATNER. "Use of the Petrifilm™ Test Kit-HEC Direct Blot Enzyme Immunoassay Method without Swab Pre-Enrichment to Screen for Low Levels of Escherichia coli O157 : H7 on Beef Carcasses by Surface Swabbing." Journal of Food Protection 60, no. 7 (July 1, 1997): 870–73. http://dx.doi.org/10.4315/0362-028x-60.7.870.

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A total of 750 beef carcasses were assayed to detect E. coli O157:H7 by surface swabbing. Each swab represented a 200-cm2 composite surface area. Escherichia coli O157:H7 was not detected in any of the carcass samples. Assays were conducted from carcass swab suspensions by direct plating on Petrifilm™ E. coli Count plates followed by an E. coli O157:H7 assay using the Petrifilm™ Test Kit-HEC direct blot enzyme immunoassay without sample pre-enrichment, and by enrichment using a modified U.S. Department of Agriculture (USDA) Petrifilm™ E. coli O157:H7 procedure. Additionally, beef slabs were inoculated with E. coli O157 :H7 to verify that recovery by the direct swab technique was at least as efficient as enrichment of excised tissue samples, which is the usual USDA method. Escherichia coli O157:H7 inoculation of 4,32, and 180 CFU/25 cm2 were designated low, medium, and high surface contamination levels, respectively. The percentage of recovery of E. coli O157:H7 using the direct swab technique without sample pre-enrichment was 60, 80, and 100% for low, medium, and high surface inoculation levels, respectively. In comparison, recovery from 25-g enrichments of ground excised samples from beef slabs containing 1.4,9.6, and 50 CFU of E. coli O157:H7 was 0, 20, and 73%, respectively. Similarly, the percent recovery of this organism from nonground excised samples containing 56 CFU/25 g enrichment was 68%, versus 100% by direct swab technique without sample pre-enrichment from beef containing 190 CFU/25 cm2 Direct surface swab tests with the 3M Petrifilm™ Test Kit-HEC without sample pre-enrichment proved to be a sensitive, nondestructive, alternate means of evaluating beef carcasses for the presence of E. coli O157:H7.
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Patiño-Burbano, Rocio Esperanza, Ana Karina Carrascal, Jorge Luis Parra-Arango, and José Luis Rodríguez-Bautista. "Assessment of a multiplex detection method for Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes in cow milk." Universitas Scientiarum 24, no. 1 (April 8, 2019): 277–94. http://dx.doi.org/10.11144/javeriana.sc24-1.aoam.

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Raw cow milk is considered one of the most important vehicles for pathogenic bacteria like Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. These three bacteria are responsible for foodborne diseases. Routine microbiological methods to detect these microorganisms in cow milk can be complicated and time consuming. The aim of this work was to evaluate a method to simultaneously detect Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes in experimentally contaminated cow milk. The assessed method combined a standard microbiological culture step, using a pre-enrichment medium that favors the growth of the three focal microorganisms: SEL broth, followed by a single PCR assay. A total of 43 interference bacterial strains were used to evaluate the method’s specificity. The detection rate for the microbiological method with standard culture media was 10 UFC/mL, and that of the PCR detection, following pre-enrichment in SEL broth, was 10 UFC/mL for S. enterica and L. monocytogenes and between 1 and 5 UFC/mL for E. coli O157:H7. The PCR method showed specificity for the reference strains. Simultaneous detection by multiple PCR using SEL broth was successful for the detection of S. enterica, E. coli O157:H7, and L. monocytogenes in samples of experimentally contaminated cow milk, featuring both a high detection rate and a high specificity. This approach promises to be a feasible routine procedure when testing milk samples in industry and public health control setups.
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HUSSEIN, HUSSEIN S., LAURIE M. BOLLINGER, and MARK R. HALL. "Growth and Enrichment Medium for Detection and Isolation of Shiga Toxin–Producing Escherichia coli in Cattle Feces." Journal of Food Protection 71, no. 5 (May 1, 2008): 927–33. http://dx.doi.org/10.4315/0362-028x-71.5.927.

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Detection methods of Shiga toxin–producing Escherichia coli (STEC) in cattle feces varied in using enrichment media containing different antibiotic combinations. To examine efficacy of a new detection method for STEC, three O157:H7 (ATCC 43889, 43890, and 43895) and 41 non-O157:H7 (members of the O1, O15, O26, O86, O103, O111, O125, O127, O128, O136, O146, O153, O158, O165, O166, and O169 serogroups) isolates were tested. These isolates were grown in tryptic soy broth for 6 h, and their concentrations were determined before inoculation of tubes containing 1 g of cattle feces (sterile [experiment 1; evaluating growth] and fresh [experiment 2; evaluating enrichment]) to simulate the high and low levels of STEC shedding by cattle (105 versus 102 CFU/g feces, respectively). Eight STEC isolates (the three O157:H7 and five non-O157:H7 selected at random) were tested at a very low level (10 CFU/g feces). The feces were incubated in 50 ml of brain heart infusion broth containing potassium tellurite, novobiocin, and vancomycin (2.5, 20, and 40 mg/liter, respectively) and cefixime (50 μg/liter) at 37°C for 12 h and tested for STEC (VTEC [verotoxin-producing E. coli]–Screen assay [agglutination immunoassay]). Potential STEC isolates were recovered, characterized biochemically, serotyped, and tested for toxin production using Vero (African green monkey kidney) cell toxicity assay and agglutination immunoassay. In both experiments, all the STEC isolates used for fecal inoculation were recovered at the concentrations tested. Our medium supported growth of and enrichment for a wide range of STEC isolates.
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Dissertations / Theses on the topic "Escherichia coli O157:H7 Microbiological assay. Immunoassay"

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Willford, John Daniel. "Development of a field-based assay for rapid detection of enterohemorrhagic Escherichia coli (EHEC)." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1663059651&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Books on the topic "Escherichia coli O157:H7 Microbiological assay. Immunoassay"

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Workshop on Methods to Isolate Escherichia Coli O157:H7 and Other Verotoxigenic E. Coli from Foods (1991 Ottawa, Ont.). Escherichia coli O157:H7 and other verotoxigenic E. coli in foods: Proceedings of a Workshop on Methods to Isolate Escherichia Coli O157:H7 and Other Verotoxigenic E. Coli from Foods, held on March 18-19, 1991 in Ottawa, Canada. Edited by Todd, E. C. D. 1939-, MacKenzie J. M, Canada Food Directorate, and Canadian Meat Council. Ottawa: Polyscience Publications, 1993.

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Conference papers on the topic "Escherichia coli O157:H7 Microbiological assay. Immunoassay"

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Gao, Yali, Philip M. Sherman, Yu Sun, and Dongqing Li. "Multiplexed High-Throughput Electrokinetically-Controlled Immunoassay on a Chip for the Detection of Specific Bacterial Antibodies in Human Serum." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42512.

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This work presents a multiplexed electrokinetically-controlled heterogeneous immunoassay that can process ten samples in parallel. The immunoassay microchip was soft-lithographically fabricated using poly(dimethylsiloxane) and glass. Controlling parameters of the electrokinetically-driven flow in the microfluidic network was determined by numerically simulating transport processes. Multiple passively adsorbed antigens captured antibodies present in samples, which then bound with TRITC-labeled detection antibodies to generate fluorescent signals. Antibodies against Escherichia coli O157:H7 and Helicobacter pylori were studied as model analytes. After conditions for antigen-coating were optimized, a 24-minute assay detected E. coli O157:H7 antibody in the concentration range of 0.02–10 μg/mL, and H. pylori antibody in the range of 0.1–50 μg/mL. In testing human serum samples, non-specific binding of serum components was effectively suppressed by using 10% (w/v) bovine serum albumin. An accuracy of 100% was achieved in detecting either E. coli O157:H7 antibody or H. pylori antibody from human serum samples. Simultaneous screening of both antibodies was also successfully demonstrated. The immunoassay chip shows an excellent potential for efficiently detecting multiple pathogenic infections in clinical environments.
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