Fast detection of 2,4,6-trinitrotoluene (TNT) at ppt level by an immunosensor based on kinetic competition

The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports arenas, theaters, and other large buildings. Security in these environments can be achieved by a set of different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of TNT occurring, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled CMOS camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of the explosive 2,4,6-trinitrotoluene (TNT). The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by PETN, RDX, and HMX. This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds.

Download Full-text

Fast Detection of 2,4,6-Trinitrotoluene (TNT) at ppt Level by a Laser-Induced Immunofluorometric Biosensor

Biosensors ◽

10.3390/bios10080089 ◽

2020 ◽

Vol 10 (8) ◽

pp. 89

Author(s):

Martin Paul ◽

Georg Tscheuschner ◽

Stefan Herrmann ◽

Michael G. Weller

Keyword(s):

Detection System ◽

Complementary Metal Oxide Semiconductor ◽

Time Frame ◽

Cross Reactivity ◽

Oxide Semiconductor ◽

Fluorescent Label ◽

Analytical Sensitivity ◽

Reactivity Test ◽

Glass Column ◽

Sports Venues

The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports venues, theaters, and other large buildings. Security in these environments can be achieved by different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of the explosive 2,4,6-trinitrotoluene (TNT), some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds. The consumption of the labeled antibody is surprisingly low: 1 mg of the reagent would be sufficient for more than one year of continuous biosensor operation.

Download Full-text

Highway Crossing Control Using PTC Technology

2013 Joint Rail Conference ◽

10.1115/jrc2013-2493 ◽

2013 ◽

Author(s):

David F. Thurston

Keyword(s):

Detection System ◽

The United States ◽

Time Frame ◽

Control Area ◽

Signal System ◽

Train Control ◽

Detection Technology ◽

Safety Case ◽

Key Features ◽

Short Time

Positive Train Control (PTC) was mandated by Congress in 2008 to be installed on an extensive network of rail carriers within the United States before the end of 2015. As such, the short time frame for implementation has dictated that several key features that could be adopted within the train control area not be considered until the base development is finished. One of the areas that has been pushed off until later is the interface to Highway crossings. This is being explored in part by Caltrain in their Communications Based Overlay Signal System (CBOSS) project that adapts Incremental Train Control System (ITCS) protocols; however this approach does not undertake the full replacement of existing technology. This paper investigates the concept of operations for PTC controlled highway crossings with the premise that the existing train detection technology will be fully replaced by PTC and its train detection system. This will allow for much reduced hardware in the field while potentially adding additional functionality. Detailed analysis of the safety case will be introduced and interface logic will be included. Additional functions such as prediction, preemption, near side control and switching scenarios will be included in the research for both freight and passenger operations and how these situations can be addressed with available PTC technology.

Download Full-text

Saliva-Dry LAMP: A Rapid Near-Patient Detection System for SARS-CoV-2.

10.21203/rs.3.rs-141322/v1 ◽

2021 ◽

Author(s):

Noah Toppings ◽

Abu Mohon ◽

Yoonjung Lee ◽

Hitendra Kumar ◽

Daniel Lee ◽

...

Keyword(s):

Limit Of Detection ◽

Detection System ◽

Turnaround Time ◽

Cross Reactivity ◽

Molecular Testing ◽

Fluorometric Detection ◽

Analytical Sensitivity ◽

Sample Collection ◽

Rt Pcr ◽

Percent Agreement

Abstract The highly infectious nature of SARS-CoV-2 necessitates the use of widespread testing to control the spread of the virus. Presently, the standard molecular testing method (reverse transcriptase-polymerase chain reaction, RT-PCR) is restricted to the laboratory, time-consuming, and costly. This increases the turnaround time for getting test results. The study sought to develop a rapid, near-patient saliva-based test for COVID-19 with similar accuracy to that of standard RT-PCR tests. A lyophilized dual-target reverse transcription-loop-mediated isothermal amplification (RT-LAMP) test with fluorometric detection by the naked eye. The assay relies on dry reagents that are room temperature stable. A device containing a centrifuge, heat block, and blue LED light system was manufactured to reduce the cost of performing the assay. This test has a limit of detection of 1 copy/µL and achieved positive percent agreement of 100% [95% CI 88.43% to 100.0%] and negative percent agreement of 96.7% [95% CI 82.78% to 99.92%] on saliva. Saliva-Dry LAMP can be completed in 105 minutes. Precision, cross-reactivity, and interfering substances analysis met international regulatory standards. The combination of ease of sample collection, dry reagents, visual detection, low capital equipment cost, and excellent analytical sensitivity make Saliva-Dry LAMP particularly useful for resource-limited settings.

Download Full-text

A rapid near-patient detection system for SARS-CoV-2 using saliva

Scientific Reports ◽

10.1038/s41598-021-92677-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Noah B. Toppings ◽

Abu Naser Mohon ◽

Yoonjung Lee ◽

Hitendra Kumar ◽

Daniel Lee ◽

...

Keyword(s):

Limit Of Detection ◽

Detection System ◽

Turnaround Time ◽

Cross Reactivity ◽

Molecular Testing ◽

Fluorometric Detection ◽

Analytical Sensitivity ◽

Sample Collection ◽

Rt Pcr ◽

Percent Agreement

AbstractThe highly infectious nature of SARS-CoV-2 necessitates the use of widespread testing to control the spread of the virus. Presently, the standard molecular testing method (reverse transcriptase-polymerase chain reaction, RT-PCR) is restricted to the laboratory, time-consuming, and costly. This increases the turnaround time for getting test results. This study sought to develop a rapid, near-patient saliva-based test for COVID-19 (Saliva-Dry LAMP) with similar accuracy to that of standard RT-PCR tests. A lyophilized dual-target reverse transcription-loop-mediated isothermal amplification (RT-LAMP) test with fluorometric detection by the naked eye was developed. The assay relies on dry reagents that are room temperature stable. A device containing a centrifuge, heat block, and blue LED light system was manufactured to reduce the cost of performing the assay. This test has a limit of detection of 1 copy/µL and achieved a positive percent agreement of 100% [95% CI 88.43% to 100.0%] and a negative percent agreement of 96.7% [95% CI 82.78–99.92%] relative to a reference standard test. Saliva-Dry LAMP can be completed in 105 min. Precision, cross-reactivity, and interfering substances analysis met international regulatory standards. The combination of ease of sample collection, dry reagents, visual detection, low capital equipment cost, and excellent analytical sensitivity make Saliva-Dry LAMP particularly useful for resource-limited settings.

Download Full-text

Validation of a Novel Diagnostic Approach Combining the VersaTREK™ System for Recovery and Real-Time PCR for the Identification of Mycobacterium chimaera in Water Samples

Microorganisms ◽

10.3390/microorganisms9051031 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1031

Author(s):

Roberto Zoccola ◽

Alessia Di Blasio ◽

Tiziana Bossotto ◽

Angela Pontei ◽

Maria Angelillo ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Limit Of Detection ◽

Detection System ◽

Bacterial Load ◽

Microbial Control ◽

Hospital Setting ◽

Sample Volume ◽

Analytical Sensitivity ◽

Initial Water

Mycobacterium chimaera is an emerging pathogen associated with endocarditis and vasculitis following cardiac surgery. Although it can take up to 6–8 weeks to culture on selective solid media, culture-based detection remains the gold standard for diagnosis, so more rapid methods are urgently needed. For the present study, we processed environmental M. chimaera infected simulates at volumes defined in international guidelines. Each preparation underwent real-time PCR; inoculates were placed in a VersaTREK™ automated microbial detection system and onto selective Middlebrook 7H11 agar plates. The validation tests showed that real-time PCR detected DNA up to a concentration of 10 ng/µL. A comparison of the isolation tests showed that the PCR method detected DNA in a dilution of ×102 CFU/mL in the bacterial suspensions, whereas the limit of detection in the VersaTREK™ was <10 CFU/mL. Within less than 3 days, the VersaTREK™ detected an initial bacterial load of 100 CFU. The detection limit did not seem to be influenced by NaOH decontamination or the initial water sample volume; analytical sensitivity was 1.5 × 102 CFU/mL; positivity was determined in under 15 days. VersaTREK™ can expedite mycobacterial growth in a culture. When combined with PCR, it can increase the overall recovery of mycobacteria in environmental samples, making it potentially applicable for microbial control in the hospital setting and also in environments with low levels of contamination by viable mycobacteria.

Download Full-text

Implementation of medium voltage remote controlled switches to improve quality performance indexes – a case study

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2020-0015 ◽

2020 ◽

Vol 21 (4) ◽

Author(s):

Julio Cezar Santos ◽

Wagner Santos ◽

Guilherme Cestaro ◽

Marcio Zamboti Fortes ◽

Henrique Henriques

Keyword(s):

Energy Distribution ◽

Electric Energy ◽

Regulatory Agencies ◽

Quality Performance ◽

Medium Voltage ◽

Fast Detection ◽

Performance Indexes ◽

Short Time ◽

Operation Center

AbstractThe growing demand for quality in the Energy Distribution Service, both by consumers and by regulatory agencies, obliges most distribution utilities to apply technologies that can be easily implemented and produce results in a short term horizon. The telecontrol technology is an essential tool every time it is necessary to fast restore the energy supply. This technology, which is completely supervised and controlled by the system operation center, allows the fast detection of a fault at a distance and switch an equipment without the aid of the operating crew, thus reducing the time that the power supply is unavailable. The present paper describes a Telecontrol Project, incorporated in an electric energy distribution utility in Brazil and compares the results in quality improvement with others usual investment actions, such as operating and maintenance procedures, laterals protection and network reinforcement. This paper shows, analyzing the results, that to improve the reliability indexes in a short time, when the company’s economic recovery is more important, the application of remotely controlled switch is more effective.

Download Full-text

Polyethylene Migration from Food Packaging on Cheese Detected by Raman and Infrared (ATR/FT-IR) Spectroscopy

Materials ◽

10.3390/ma14143872 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3872

Author(s):

Klytaimnistra Katsara ◽

George Kenanakis ◽

Zacharias Viskadourakis ◽

Vassilis M. Papadakis

Keyword(s):

Vibrational Spectroscopy ◽

Food Packaging ◽

Time Frame ◽

Low Density Polyethylene ◽

Low Density ◽

Ft Ir ◽

Comparative Results ◽

Short Time ◽

And Storage ◽

Ft Ir Spectroscopy

For multiple years, food packaging migration has been a major concern in food and health sciences. Plastics, such as polyethylene, are continuously utilized in food packaging for preservation and easy handling purposes during transportation and storage. In this work, three types of cheese, Edam, Kefalotyri and Parmesan, of different hardness were studied under two complementary vibrational spectroscopy methods, ATR-FTIR and Raman spectroscopy, to determine the migration of low-density polyethylene from plastic packaging to the surface of cheese samples. The experimental duration of this study was set to 28 days due to the degradation time of the selected cheese samples, which is clearly visible after 1 month in refrigerated conditions at 4 °C. Raman and ATR-FTIR measurements were performed at a 4–3–4–3 day pattern to obtain comparative results. Initially, consistency/repeatability measurement tests were performed on Day0 for each sample of all cheese specimens to understand if there is any overlap between the characteristic Raman and ATR-FTIR peaks of the cheese with the ones from the low-density polyethylene package. We provide evidence that on Day14, peaks of low-density polyethylene appeared due to polymeric migration in all three cheese types we tested. In all cheese samples, microbial outgrowth started to develop after Day21, as observed visually and under the bright-field microscope, causing peak reverse. Food packaging migration was validated using two different approaches of vibrational spectroscopy (Raman and FT-IR), revealing that cheese needs to be consumed within a short time frame in refrigerated conditions at 4 °C.

Download Full-text

Gait Phase Detection Based on Muscle Deformation with Static Standing-Based Calibration

Sensors ◽

10.3390/s21041081 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1081

Author(s):

Tamon Miyake ◽

Shintaro Yamamoto ◽

Satoshi Hosono ◽

Satoshi Funabashi ◽

Zhengxue Cheng ◽

...

Keyword(s):

Learning Algorithm ◽

Detection System ◽

Calibration Method ◽

Detection Algorithm ◽

Video Data ◽

Detection Accuracy ◽

Phase Detection ◽

Gait Phase ◽

Logistic Regression Algorithm ◽

Short Time

Gait phase detection, which detects foot-contact and foot-off states during walking, is important for various applications, such as synchronous robotic assistance and health monitoring. Gait phase detection systems have been proposed with various wearable devices, sensing inertial, electromyography, or force myography information. In this paper, we present a novel gait phase detection system with static standing-based calibration using muscle deformation information. The gait phase detection algorithm can be calibrated within a short time using muscle deformation data by standing in several postures; it is not necessary to collect data while walking for calibration. A logistic regression algorithm is used as the machine learning algorithm, and the probability output is adjusted based on the angular velocity of the sensor. An experiment is performed with 10 subjects, and the detection accuracy of foot-contact and foot-off states is evaluated using video data for each subject. The median accuracy is approximately 90% during walking based on calibration for 60 s, which shows the feasibility of the static standing-based calibration method using muscle deformation information for foot-contact and foot-off state detection.

Download Full-text

Breeding Strategies to Improve Miscanthus as a Sustainable Source of Biomass for Bioenergy and Biorenewable Products

Agronomy ◽

10.3390/agronomy9110673 ◽

2019 ◽

Vol 9 (11) ◽

pp. 673 ◽

Cited By ~ 7

Author(s):

John Clifton-Brown ◽

Kai-Uwe Schwarz ◽

Danny Awty-Carroll ◽

Antonella Iurato ◽

Heike Meyer ◽

...

Keyword(s):

Significant Contribution ◽

Perennial Grass ◽

Time Frame ◽

Eastern Asia ◽

Germplasm Collections ◽

Naturally Occurring ◽

Wide Range ◽

Yield Quality ◽

Short Time ◽

Commercial Expansion

Miscanthus, a C4 perennial grass native to Eastern Asia, is being bred to provide biomass for bioenergy and biorenewable products. Commercial expansion with the clonal hybrid M. × giganteus is limited by low multiplication rates, high establishment costs and drought sensitivity. These limitations can be overcome by breeding more resilient Miscanthus hybrids propagated by seed. Naturally occurring fast growing indigenous Miscanthus species are found in diverse environments across Eastern Asia. The natural diversity provides for plant breeders, the genetic resources to improve yield, quality, and resilience for a wide range of climates and adverse abiotic stresses. The challenge for Miscanthus breeding is to harness the diversity through selections of outstanding wild types, parents, and progenies over a short time frame to deploy hybrids that make a significant contribution to a world less dependent on fossil resources. Here are described the strategies taken by the Miscanthus breeding programme at Aberystwyth, UK and its partners. The programme built up one of the largest Miscanthus germplasm collections outside Asia. We describe the initial strategies to exploit the available genetic diversity to develop varieties. We illustrate the success of combining diverse Miscanthus germplasm and the selection criteria applied across different environments to identify promising hybrids and to develop these into commercial varieties. We discuss the potential for molecular selections to streamline the breeding process.

Download Full-text

COBAS AMPLICOR: fully automated RNA and DNA amplification and detection system for routine diagnostic PCR

Clinical Chemistry ◽

10.1093/clinchem/42.12.1915 ◽

1996 ◽

Vol 42 (12) ◽

pp. 1915-1923 ◽

Cited By ~ 67

Author(s):

N DiDomenico ◽

H Link ◽

R Knobel ◽

T Caratsch ◽

W Weschler ◽

...

Keyword(s):

Nucleic Acids ◽

Internal Control ◽

Detection System ◽

Dna Amplification ◽

Cross Reactivity ◽

Diagnostic Pcr ◽

Thermal Cycler ◽

Paramagnetic Microparticles ◽

Rna And Dna ◽

Single Reaction

Abstract The COBAS AMPLICOR system automates amplification and detection of target nucleic acids, making diagnostic PCR routine for a variety of infectious diseases. The system contains a single thermal cycler with two independently regulated heating/cooling blocks, an incubator, a magnetic particle washer, a pipettor, and a photometer. Amplified products are captured on oligonucleotide-coated paramagnetic microparticles and detected with use of an avidin-horseradish peroxidase (HRP) conjugate. Concentrated solutions of amplicon or HRP were pipetted without detectable carryover. Amplified DNA was detected with an intraassay CV of < 4.5%; the combined intraassay CV for amplification and detection was < 15%. No cross-reactivity was observed when three different target nucleic acids were amplified in a single reaction and detected with three target-specific capture probes. The initial COBAS AMPLICOR menu includes qualitative tests for diagnosing infections with Chlamydia trachomatis, Neisseria gonorrhoeae, Mycobacterium tuberculosis, and hepatitis C virus. All tests include an optional Internal Control to provide assurance that specimens are successfully amplified and detected.

Download Full-text