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Through the looking-glass - Recent developments in reflectometry open new possibilities for biosensor applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Fourier spotting: a novel setup for single-color reflectometry. Anal Bioanal Chem 2022; 414:1787-1796. [PMID: 34997253 PMCID: PMC8791914 DOI: 10.1007/s00216-021-03802-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/11/2021] [Accepted: 11/23/2021] [Indexed: 11/22/2022]
Abstract
Single-color reflectrometry is a sensitive and robust detection method in optical biosensor applications, for example for bioanalysis. It is based on the interference of reflected monochromatic radiation and is label free. We present a novel setup for single-color reflectometry based on the patented technology of Berner et al. from 2016. Tilting areas of micro-mirrors allow us to encode the optical reflection signal of an analyte and reference channel into a particular carrier frequency with the amplitude being proportional to the local reflection. Therefore, a single photodiode is sufficient to collect the signals from both channels simultaneously. A 180∘ phase shift in the tilt frequency of two calibrated micro-mirror areas leads to a superposition of the analyte and reference signal which enables an efficient reduction of the baseline offset and potential baseline offset drift. A performance test reveals that we are able to detect changes of the refractive index n down to Δn < 0.01 of saline solutions as regents. A further test validates the detection of heterogeneous binding interaction. This test compromises immobilized testosterone-bovine serum albumin on a three-dimensional layer of biopolymer as ligand and monoclonal anti-testosterone antibodies as analyte. Antibody/antigen binding induces a local growth of the biolayer and change in the refractive index, which is measured via the local change of the reflection. Reproducible measurements enable for the analysis of the binding kinetics by determining the affinity constant KA = 1.59 × 10− 7 M− 1. In summary, this work shows that the concept of differential Fourier spotting as novel setup for single-color reflectometry is suitable for reliable bioanalysis. Graphical Abstract ![]()
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Abstract
Emerging research in biosensors has attracted much attention worldwide, particularly in response to the recent pandemic outbreak of coronavirus disease 2019 (COVID-19). Nevertheless, initiating research in biosensing applied to the diagnosis of diseases is still challenging for researchers, be it in the preferences of biosensor platforms, selection of biomarkers, detection strategies, or other aspects (e.g., cutoff values) to fulfill the clinical purpose. There are two sides to the development of a diagnostic tool: the biosensor development side and the clinical side. From the development side, the research engineers seek the typical characteristics of a biosensor: sensitivity, selectivity, linearity, stability, and reproducibility. On the other side are the physicians that expect a diagnostic tool that provides fast acquisition of patient information to obtain an early diagnosis or an efficient patient stratification, which consequently allows for making assertive and efficient clinical decisions. The development of diagnostic devices always involves assay developer researchers working as pivots to bridge both sides whose role is to find detection strategies suitable to the clinical needs by understanding (1) the intended use of the technology and its basic principle and (2) the preferable type of test: qualitative or quantitative, sample matrix challenges, biomarker(s) threshold (cutoff value), and if the system requires a mono- or multiplex assay format. This review highlights the challenges for the development of biosensors for clinical assessment and its broad application in multidisciplinary fields. This review paper highlights the following biosensor technologies: magnetoresistive (MR)-based, transistor-based, quartz crystal microbalance (QCM), and optical-based biosensors. Its working mechanisms are discussed with their pros and cons. The article also gives an overview of the most critical parameters that are optimized by developing a diagnostic tool.
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Comparison of Dilution on Eastern Box Turtle ( Terrapene carolina carolina) and Marine Toad (Rhinella marinus) Blood Parameters as Measured on a Portable Chemistry Analyzer. Vet Med Int 2020; 2020:8843058. [PMID: 32908664 PMCID: PMC7474372 DOI: 10.1155/2020/8843058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 11/18/2022] Open
Abstract
Biochemical testing is an important clinical tool in evaluating the physiology of reptiles and amphibians. Suitable point of care analyzers can allow for rapid delivery of results, but small patient size can inhibit sufficient sample collection. This study evaluated the utility of sample dilution with sterile distilled water as a means of biochemical evaluation when sample volume is limited. Blood was collected from 12 eastern box turtles (Terrapene carolina carolina) and 12 marine toads (Rhinella marinus) and analyzed via i-STAT CHEM8+ cartridges. Two undiluted samples and two samples diluted 1 : 1 with sterile water were evaluated immediately following collection for each animal in the study. Analytes reported in the diluted samples were limited to glucose, ionized calcium, and total carbon dioxide. The expected dilution ratio value of diluted to undiluted samples was 0.5, of which glucose in both turtles and toads was nearest. Dilution ratio values for ionized calcium, however, were higher than expected in both turtles and toads. Sample dilution is not recommended for most analytes included on the CHEM8+ cartridge due to values occurring outside the limits of detection for the analyzer. Glucose and ionized calcium values obtained on diluted samples should be interpreted with caution but may provide clinical utility in reptile and amphibian patients where sample volume is limited.
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Krämer SD, Wöhrle J, Rath C, Roth G. Anabel: An Online Tool for the Real-Time Kinetic Analysis of Binding Events. Bioinform Biol Insights 2019; 13:1177932218821383. [PMID: 30670920 PMCID: PMC6328958 DOI: 10.1177/1177932218821383] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 11/23/2018] [Indexed: 11/17/2022] Open
Abstract
Anabel (Analysis of binding events + l) is an open source online software tool (www.skscience.org/anabel) for the convenient analysis of molecular binding interactions. Currently, exported datasets from Biacore (surface plasmon resonance [SPR]), FortéBio (biolayer interference [BLI]), and Biametrics (single color reflectometry [SCORE]) can be uploaded and evaluated in Anabel using 2 different evaluation methods. Moreover, a universal data template format is provided to upload any other binding dataset to Anabel. This enables an easier comparison of different analysis methods for all users. Furthermore, a guide was established in Anabel to help inexperienced users to obtain optimal results. In addition, expert features can be used to optimize and control the fit of the binding model to the measured data. We tried to make the process of fitting and evaluating as easy as possible through the use of an intuitive user interface. At the end of every analysis, a single excel file, containing all results and graphs of the performed analysis, can be downloaded.
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Affiliation(s)
- Stefan D Krämer
- Center for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany.,Faculty for Biology, University of Freiburg, Freiburg, Germany
| | - Johannes Wöhrle
- Center for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany.,Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Christin Rath
- Center for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany.,Faculty for Biology, University of Freiburg, Freiburg, Germany.,BioCopy GmbH, Freiburg, Germany.,BIOSS Center for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Günter Roth
- Center for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany.,Faculty for Biology, University of Freiburg, Freiburg, Germany.,BioCopy GmbH, Freiburg, Germany.,BIOSS Center for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
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Song D, Yang R, Wang H, Fang S, Liu Y, Long F, Zhu A. Development of dual-color total internal reflection fluorescence biosensor for simultaneous quantitation of two small molecules and their affinity constants with antibodies. Biosens Bioelectron 2018; 126:824-830. [PMID: 30602264 DOI: 10.1016/j.bios.2018.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A novel dual-color total internal reflection fluorescence biosensor (DTB) was successfully developed for the simultaneous detection of two small molecules based on a simple optical structure and the time resolved effect of fiber optic switch. The DTB employed a single-multi mode fiber optic coupler instead of a sophisticated confocal optical system for the transmission of two excitation lights and dual-color fluorescence, and a photodiode detector instead of photomultiplier for the simultaneous detection of dual-color fluorescence. The compact optical design of DTB improved its optical transmission efficiency and detection sensitivity because of no requirement of numerous optical separation elements and rigorous optical alignment. The DTB was applied for the simultaneous detection of 2,4-Bisphenol-A (BPA) and 2,4-Dichlorophenoxyacetic acid (2,4-D) using one bifunctional fiber optic bio-probe modified by two hapten-protein conjugates. When the mixture of Cy5.5 labeled anti-2,4-D antibody and Pacific Blue dye labeled anti-BPA antibody was introduced over the surface of the bio-probe, they bound with their respective hapten-protein conjugate immobilized onto the bio-probe. Based on the time-resolved effect of fiber optic switch, two fluorescence dyes were alternatively excited by 635 nm and 405 nm laser lights and simultaneously detected by one photodiode detector. Taking indirect competitive immunoassay principle, BPA and 2,4-D were simultaneously detected using the DTB with high sensitivity, accuracy, and rapidity. The quantitation of affinity constants between small molecules and their antibodies was also achieved based on the proposed theory. The DTB provides a flexible and powerful platform for simultaneously sensitive quantitation of multiple targets and the affinity constants of biomolecular interactions.
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Affiliation(s)
- Dan Song
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China
| | - Rong Yang
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China
| | - Hongliang Wang
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China
| | - Sunyan Fang
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China
| | - Yanping Liu
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China
| | - Feng Long
- School of Environment and Natural Resource, Renmin University of China, 100872 Beijing, China.
| | - Anna Zhu
- Research Institute of Chemical Defense, Academy of Military Sciences PLA China, Beijing 102205, China; State Key Laboratory of NBC Protection FOR Civilian, Beijing 102205, China.
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A Fluorescent Biosensors for Detection Vital Body Fluids' Agents. SENSORS 2018; 18:s18082357. [PMID: 30042294 PMCID: PMC6111579 DOI: 10.3390/s18082357] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/13/2018] [Accepted: 07/20/2018] [Indexed: 12/18/2022]
Abstract
The clinical applications of sensing tools (i.e., biosensors) for the monitoring of physiologically important analytes are very common. Nowadays, the biosensors are being increasingly used to detect physiologically important analytes in real biological samples (i.e., blood, plasma, urine, and saliva). This review focuses on biosensors that can be applied to continuous, time-resolved measurements with fluorescence. The material presents the fluorescent biosensors for the detection of neurotransmitters, hormones, and other human metabolites as glucose, lactate or uric acid. The construction of microfluidic devices based on fluorescence uses a variety of materials, fluorescent dyes, types of detectors, excitation sources, optical filters, and geometrical systems. Due to their small size, these devices can perform a full analysis. Microfluidics-based technologies have shown promising applications in several of the main laboratory techniques, including blood chemistries, immunoassays, nucleic-acid amplification tests. Of the all technologies that are used to manufacture microfluidic systems, the LTCC technique seems to be an interesting alternative. It allows easy integration of electronic and microfluidic components on a single ceramic substrate. Moreover, the LTCC material is biologically and chemically inert, and is resistant to high temperature and pressure. The combination of all these features makes the LTCC technology particularly useful for implementation of fluorescence-based detection in the ceramic microfluidic systems.
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Bender J, Bognar S, Camagna M, Donauer JAM, Eble JW, Emig R, Fischer S, Jesser R, Keilholz L, Kokotek DMU, Neumann J, Nicklaus S, Oude Weernink RRQPT, Stühn LG, Wössner N, Krämer SD, Schwenk P, Gensch N, Roth G, Ulbrich MH. Multiplexed antibody detection from blood sera by immobilization of in vitro expressed antigens and label-free readout via imaging reflectometric interferometry (iRIf). Biosens Bioelectron 2018; 115:97-103. [PMID: 29803867 DOI: 10.1016/j.bios.2018.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 04/18/2018] [Accepted: 05/10/2018] [Indexed: 11/30/2022]
Abstract
The detection of antibodies from blood sera is crucial for diagnostic purposes. Miniaturized protein assays in combination with microfluidic setups hold great potential by enabling automated handling and multiplexed analyses. Yet, the separate expression, purification, and storage of many individual proteins are time consuming and limit applicability. In vitro cell-free expression has been proposed as an alternative procedure for the generation of protein assays. We report the successful in vitro expression of different model proteins from DNA templates with an optimized expression mix. His10-tagged proteins were specifically captured and immobilized on a Ni-NTA coated sensor surface directly from the in vitro expression mix. Finally, the specific binding of antibodies from rabbit-derived blood sera to the immobilized proteins was monitored by imaging reflectometric interferometry (iRIf). Antibodies in the blood sera could be identified by binding to the respective epitopes with minimal cross reactivity. The results show the potential of in vitro expression and label-free detection for binding assays in general and diagnostic purposes in specific.
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Affiliation(s)
- Julian Bender
- Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Sabine Bognar
- Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Maurizio Camagna
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Julia A M Donauer
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Julian W Eble
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Ramona Emig
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Sabrina Fischer
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Rabea Jesser
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Luisa Keilholz
- Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Daniel M U Kokotek
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Julika Neumann
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Simon Nicklaus
- Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Ricardo R Q P T Oude Weernink
- Institute of Physics, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Lara G Stühn
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Nathalie Wössner
- Faculty of Chemistry and Pharmacy, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Stefan D Krämer
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; ZBSA - Center for Biological Systems Analysis, University of Freiburg, 79104 Freiburg, Germany
| | - Philipp Schwenk
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
| | - Nicole Gensch
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Günter Roth
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; ZBSA - Center for Biological Systems Analysis, University of Freiburg, 79104 Freiburg, Germany.
| | - Maximilian H Ulbrich
- Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; Renal Division, Freiburg University Medical Center, 79106 Freiburg, Germany.
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Neethirajan S, Ragavan K, Weng X. Agro-defense: Biosensors for food from healthy crops and animals. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2017.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Proll G, Markovic G, Fechner P, Proell F, Gauglitz G. Reflectometric Interference Spectroscopy. Methods Mol Biol 2017; 1571:207-220. [PMID: 28281258 DOI: 10.1007/978-1-4939-6848-0_13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Reflectometry is classified in comparison to the commercialized refractometric surface plasmon resonance. The advantages of direct optical detection depend on a sophisticated surface chemistry resulting negligible nonspecific binding and high loading with recognition sites at the biopolymer sensitive layer of the transducer. Elaborate details on instrumental realization and surface chemistry are discussed for optimum application of reflectometric interference spectroscopy (RIfS). A standard protocol for a binding inhibition assay is given. It overcomes principal problems of any direct optical detection technique.
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Affiliation(s)
- Guenther Proll
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, 72076, Tuebingen, Germany. .,Biametrics GmbH, Waldhaeuser Str. 64, 72076, Tuebingen, Germany.
| | - Goran Markovic
- Biametrics GmbH, Waldhaeuser Str. 64, 72076, Tuebingen, Germany
| | - Peter Fechner
- Biametrics GmbH, Waldhaeuser Str. 64, 72076, Tuebingen, Germany
| | - Florian Proell
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, 72076, Tuebingen, Germany.,Biametrics GmbH, Waldhaeuser Str. 64, 72076, Tuebingen, Germany
| | - Guenter Gauglitz
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle 18, 72076, Tuebingen, Germany
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Cummins BM, Ligler FS, Walker GM. Point-of-care diagnostics for niche applications. Biotechnol Adv 2016; 34:161-76. [PMID: 26837054 PMCID: PMC4833668 DOI: 10.1016/j.biotechadv.2016.01.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/28/2016] [Accepted: 01/28/2016] [Indexed: 01/26/2023]
Abstract
Point-of-care or point-of-use diagnostics are analytical devices that provide clinically relevant information without the need for a core clinical laboratory. In this review we define point-of-care diagnostics as portable versions of assays performed in a traditional clinical chemistry laboratory. This review discusses five areas relevant to human and animal health where increased attention could produce significant impact: veterinary medicine, space travel, sports medicine, emergency medicine, and operating room efficiency. For each of these areas, clinical need, available commercial products, and ongoing research into new devices are highlighted.
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Affiliation(s)
- Brian M Cummins
- Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill and North Carolina State University, Raleigh, NC, 27695, USA
| | - Frances S Ligler
- Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill and North Carolina State University, Raleigh, NC, 27695, USA
| | - Glenn M Walker
- Joint Department of Biomedical Engineering, University of North Carolina - Chapel Hill and North Carolina State University, Raleigh, NC, 27695, USA.
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