scholarly journals Hartman interferometer: versatile integrated optic sensor for label-free, real-time quantification of nucleic acids, proteins, and pathogens

1997 ◽  
Vol 43 (9) ◽  
pp. 1757-1763 ◽  
Author(s):  
Bernard H Schneider ◽  
John G Edwards ◽  
Nile F Hartman
Keyword(s):  
Real Time ◽  
Optical Sensors ◽  
Evanescent Wave ◽  
Low Cost ◽  
Refractive Index Change ◽  
Polarized Light ◽  
Gene Probe ◽  
Label Free ◽  
Optic Sensor ◽  
Wide Range

Abstract The Hartman interferometer, a proprietary integrated optic sensor, provides a basis for a broad range of biomedical diagnostics, including antibody-based and gene probe-based assays. As with other evanescent-wave optical sensors, the interferometer measures the refractive index change resulting from biomolecular binding on a waveguide surface. The exciting promise of evanescent-wave sensors lies, in general, in their potential to be used as label-free, real-time transducers that can operate in a true mix-and-read fashion and provide fast, quantitative results. One of the major issues facing their development, however, is creating a simple, low-cost configuration for multianalyte testing. The Hartman interferometer addresses this challenge by relying on linearly polarized light and a planar waveguide format, thereby avoiding the problems associatedwith circular polarization and channel waveguides. We report preliminary experiments that demonstrate the applicability of this sensor configuration to detection of a wide range of protein, nucleic acid, and pathogen analytes.

scholarly journals Real-Time Low-Cost Speed Monitoring and Control of Three-Phase Induction Motor via a Voltage/Frequency Control Approach

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ali Hmidet ◽  
Olfa Boubaker
Keyword(s):  
Real Time ◽  
Induction Motor ◽  
Closed Loop ◽  
Low Cost ◽  
Closed Loop Control ◽  
Loop Control ◽  
Control Approach ◽  
Three Phase ◽  
Wide Range ◽  
Voltage Frequency

In this paper, a new design of a real-time low-cost speed monitoring and closed-loop control of the three-phase induction motor (IM) is proposed. The proposed solution is based on a voltage/frequency (V/F) control approach and a PI antiwindup regulator. It uses the Waijung Blockset which considerably alleviates the heaviness and the difficulty of the microcontroller’s programming task incessantly crucial for the implementation and the management of such complex applications. Indeed, it automatically generates C codes for many types of microcontrollers like the STM32F4 family, also used in this application. Furthermore, it offers a cost-effective design reducing the system components and increasing its efficiency. To prove the efficiency of the suggested design, not only simulation results are carried out for a wide range of variations in load and reference speed but also experimental assessment. The real-time closed-loop control performances are proved using the aMG SQLite Data Server via the UART port board, whereas Waijung WebPage Designer (W2D) is used for the web monitoring task. Experimental results prove the accuracy and robustness of the proposed solution.

LZER0: GNSS cost-effective real-time positioning applied to landslide monitoring

2020 ◽  
Author(s):  
Lavinia Tunini ◽  
David Zuliani ◽  
Paolo Fabris ◽  
Marco Severin
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Low Cost ◽  
Cost Effective ◽  
Single Frequency ◽  
Landslide Monitoring ◽  
Natural Risk ◽  
Near Surface ◽  
Landslide Event ◽  
Wide Range

<p>The Global Navigation Satellite Systems (GNSS) provide a globally extended dataset of primordial importance for a wide range of applications, such as crustal deformation, topographic measurements, or near surface processes studies. However, the high costs of GNSS receivers and the supporting software can represent a strong limitation for the applicability to landslide monitoring. Low-cost tools and techniques are strongly required to face the plausible risk of losing the equipment during a landslide event.</p><p>Centro di Ricerche Sismologiche (CRS) of Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS in collaboration with SoluTOP, in the last years, has developed a cost-effective GNSS device, called LZER0, both for post-processing and real-time applications. The aim is to satisfy the needs of both scientific and professional communities which require low-cost equipment to increase and improve the measurements on structures at risk, such as landslides or buildings, without losing precision.</p><p>The landslide monitoring system implements single-frequency GNSS devices and open source software packages for GNSS positioning, dialoguing through Linux shell scripts. Furthermore a front-end web page has been developed to show real-time tracks. The system allows measuring real-time surface displacements with a centimetre precision and with a cost ten times minor than a standard RTK GPS operational system.</p><p>This monitoring system has been tested and now applied to two landslides in NE- Italy: one near Tolmezzo municipality and one near Brugnera village. Part of the device development has been included inside the project CLARA 'CLoud plAtform and smart underground imaging for natural Risk Assessment' funded by the Italian Ministry of Education, University and Research (MIUR).</p>

scholarly journals Improved LC-MS chromatographic alignment increases the accuracy of label-free quantitative proteomics: Comparison of spectral counting versus ion intensity-based proteomic quantification strategies

2017 ◽  
Author(s):  
Daniel H.J. Ng ◽  
Jonathan D. Humphries ◽  
Julian N. Selley ◽  
Stacey Warwood ◽  
David Knight ◽  
...  
Keyword(s):  
Cell Biology ◽  
Low Cost ◽  
Quantitative Description ◽  
Protein Quantification ◽  
Global Changes ◽  
Label Free ◽  
Spectral Counting ◽  
Differential Abundance ◽  
Mass Spectrometers ◽  
Wide Range

AbstractThe ability to provide an unbiased qualitative and quantitative description of the global changes to proteins in a cell or an organism would permit the systems-wide study of complex biological systems. Label-free quantitative shotgun proteomic strategies (including LC-MS ion intensity quantification and spectral counting) are attractive because of their relatively low cost, ease of implementation, and the lack of multiplexing restrictions when comparing multiple samples. Owing to improvements in the resolution and sensitivity of mass spectrometers, and the availability of analytical software packages, protein quantification by LC-MS ion intensity has increased in popularity. Here, we have addressed the importance of chromatographic alignment on protein quantification, and then assessed how spectral counting compares to ion intensity-based proteomic quantification. Using a spiked-in protein strategy, we analysed two situations that commonly arise in the application of proteomics to cell biology: (i) samples with a small number of proteins of differential abundance in a larger non-changing background, and (ii) samples with a larger number of proteins of differential abundance. To perform these assessments on biologically relevant samples, we used isolated integrin adhesion complexes (IACs). Technical replicate analysis of isolated IACs resulted in a range of alignment scores using the Progenesis QI software package and demonstrated that higher LC-MS chromatographic alignment scores increased the precision of protein quantification. Furthermore, implementation of a simple sample batch-running strategy enabled good chromatographic alignment for hundreds of samples over multiple batches. Finally, we applied the sample batch-running strategy and compared quantification by LC-MS ion intensity to spectral counting and found that quantification by LC-MS ion intensity was more accurate and precise. In summary, these results demonstrate that chromatographic alignment is important for precise and accurate protein quantification based on LC-MS ion intensity and accordingly we present a simple sample re-ordering strategy to facilitate improved alignment. These findings are not only relevant to label-free quantification using Progenesis QI but may be useful to the wide range of MS-based quantification strategies that rely on chromatographic alignment.

scholarly journals Colorimetric Sensing with Gold Nanoparticles on Electrowetting-Based Digital Microfluidics

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1423
Author(s):  
Zhen Gu ◽  
Jing-Jing Luo ◽  
Le-Wei Ding ◽  
Bing-Yong Yan ◽  
Jia-Le Zhou ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Low Cost ◽  
Digital Microfluidics ◽  
High Sensitivity ◽  
Bulk Solution ◽  
Label Free ◽  
Colorimetric Sensing ◽  
Wide Range ◽  
The Stability ◽  
Digital Microfluidic

Digital microfluidic (DMF) has been a unique tool for manipulating micro-droplets with high flexibility and accuracy. To extend the application of DMF for automatic and in-site detection, it is promising to introduce colorimetric sensing based on gold nanoparticles (AuNPs), which have advantages including high sensitivity, label-free, biocompatibility, and easy surface modification. However, there is still a lack of studies for investigating the movement and stability of AuNPs for in-site detection on the electrowetting-based digital microfluidics. Herein, to demonstrate the ability of DMF for colorimetric sensing with AuNPs, we investigated the electrowetting property of the AuNPs droplets on the hydrophobic interface of the DMF chip and examined the stability of the AuNPs on DMF as well as the influence of evaporation to the colorimetric sensing. As a result, we found that the electrowetting of AuNPs fits to a modified Young–Lippmann equation, which suggests that a higher voltage is required to actuate AuNPs droplets compared with actuating water droplets. Moreover, the stability of AuNPs was maintained during the processing of electrowetting. We also proved that the evaporation of droplets has a limited influence on the detections that last several minutes. Finally, a model experiment for the detection of Hg2+ was carried out with similar results to the detections in bulk solution. The proposed method can be further extended to a wide range of AuNPs-based detection for label-free, automatic, and low-cost detection of small molecules, biomarkers, and metal ions.

Nanografting of Polymer Brushes on Gold Substrate by RAFT-RIGP

2021 ◽  
Vol 7 (1) ◽  
pp. 5
Author(s):  
Bin Jeremiah D. Barba ◽  
Patricia Nyn L. Heruela ◽  
Patrick Jay E. Cabalar ◽  
John Andrew A. Luna ◽  
Allan Christopher C. Yago ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Optical Sensors ◽  
Self Assembly ◽  
Polymer Brushes ◽  
Incident Light ◽  
Organosulfur Compounds ◽  
Layer By Layer ◽  
Label Free ◽  
Sensing Applications ◽  
Wide Range

Optical sensors based on surface plasmon resonance (SPR) have made great strides in the detection of various chemical and biological analytes. A surface plasmon is a bound, non-radiative evanescent wave generated as resonant electrons on a metal–dielectric surface to absorb energy from an incident light. As analytes bind to a functionalized metal substrate, the refractometric response generated can be used for quantitation with great selectivity, sensitivity, and capacity for label-free real-time analysis. Polymer nanobrushes are ideal recognition elements because of their greater surface area and their wide range of functional versatility. Here, we introduce a simple “grafting-from” method to covalently attach nanometer-thick polymer chains on a gold surface. Nanografting on gold-coated BK-7 glass was performed in two steps: (1) self-assembly of organosulfur compounds; and (2) RAFT-mediated radiation-induced graft polymerization (RAFT-RIGP) of polyglycidyl methacrylate (PGMA). Surface modification was monitored and verified using FTIR and SPR. Layer-by-layer thickness calculated based on Winspall 3.02 simulation fitted with experimental SPR curves showed successful self-assembly of 1-dodecanethiol (DDT) monolayer with thickness measuring 1.4 nm. These alkane chains of DDT served as the graft initiation sites for RAFT-RIGP. Nanografting was controlled by adjusting the absorbed dose in the presence of chain transfer agent, 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid. The molecular weight of grafted polymers measuring 2.8 and 4.3 kDa corresponded to a thickness increase of 3.6 and 7.9 nm, respectively. These stable nanografted gold substrates may be further functionalized for sensing applications.

Description of a High-Profit Combination of Low-Cost Real-Time Survey Management Practices Used to Optimize Reservoir Landing in Unfamiliar Deep Offshore Geological Environment

2021 ◽  
Author(s):  
Fabien Momot ◽  
Marie-Jocelyn Comte ◽  
Chloé Lacaze ◽  
Anas Sikal ◽  
Efficience Balou ◽  
...  
Keyword(s):  
Real Time ◽  
Management Practices ◽  
Low Cost ◽  
Vertical Displacement ◽  
Uncertainty Reduction ◽  
Vertical Position ◽  
Reservoir Model ◽  
Data Set ◽  
Wide Range ◽  
Operational Time

Abstract After a first part of the drilling campaign, including about 10 wells and branches achieved within two years, the operator started questioning the geological reservoir model and reserves implications for the field Offshore Congo. Considering the potential economic impact of this development, the decision was made to reduce wellbore positioning uncertainty relying on optimization and survey QAQC processes that could be applied without adding cost of extra equipment, operational time or personnel. With more than 10 wells drilled using recent while drilling measurement and directional tools in the same environment, a wide range of wellbore positioning information was available for analysis, post-correction, and geological/reservoir model deeper understanding. Also, investigation was done to recover existing geomagnetic data acquired during the geophysical campaign. Thanks to this extensive data set, enhanced wellbores positioning was implemented using meticulous combination of processes. The "process" overall impact is often underestimated while most of the data is already available. For lateral positioning correction, it included the processing of geomagnetic IFR data over the Moho field associated to Multi Station Correction. For vertical repositioning, BHA sag correction was applied with scrutinous assessment of residual sag uncertainty and detailed analysis of continuous survey data. This robust, cost-effective, and valuable solution was chosen to be applied by the operator in the Moho field. The process was first applied post-drilling to evaluate the level of improvement that could be brought to another well also exposed to challenging trajectory context (ERD 2 with reduced target 25 × 50 m at almost 8000m MD/RT). It confirmed that the achievable uncertainty reduction would meet well objectives without adding any risk or operational time nor jeopardizing wellbore positioning and collision avoidance. Thus, it brought up to 50 to 60% of uncertainty reduction and about 30m lateral and 3m vertical displacement. The reduction of the uncertainty and trajectory adjustment allowed to enhance geologic context understanding. The vertical position of the well was offset following this revision. This had a 5% consequence in term of oil layer thickness for this well. Then, the team designed and rolled out to the operator and contractors an execution strategy and operational workflow including remote monitoring with near real-time survey QAQC that would ensure the best correction process customized for the specific drilling challenges. This monitoring enabled reducing the ellipsoid to ~20 by 50m radius at TD = 7618m. This allowed entering in the reservoir at the exact top of the structure, behind the fault that was the optimum in term of reserves and secured 90% of potential reserves of this well. The operator's choice of valuing the available information to enhance their asset is a very interesting way to optimize the past efforts put in wellbore positioning to face the current economically constrained environment.

An Experimental Autonomous Path Tracking Mobile Robot

2009 ◽  
Vol 62-64 ◽  
pp. 181-186 ◽  
Author(s):  
Hasitha M. B. Senanayake ◽  
Olaitan Akinsanmi ◽  
Muhammed Bashir Mu’azu
Keyword(s):  
Mobile Robot ◽  
Real Time ◽  
Optical Sensors ◽  
Low Cost ◽  
Path Tracking ◽  
Detection And Tracking ◽  
Embedded Controller ◽  
Important Notion ◽  
Path Detection

Autonomous Vehicular Navigation poses interesting challenges and, Automatically Guided Vehicle (AGV) Path Tracking presents an important notion in real-time Mechatronics applications. This paper describes the design of a Path Tracking Automatically Guided Vehicle that is capable of autonomously navigating a predefined path on a level navigating plane and, the designed AGV successfully completed a 3.42 meter test course in precisely 2 minutes 16 seconds. The AGV comprises a PIC16F84A microcontroller utilized as an embedded controller and, an array of Infrared reflective optical sensors to enable path detection and tracking. Among the primary objectives of the design that were achieved was to design the low-cost mobile robot from component parts sourced locally, from within Nigeria.

scholarly journals Emerging Electrochemical Sensors for Real-Time Detection of Tetracyclines in Milk

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 232
Author(s):  
Magdalena R. Raykova ◽  
Damion K. Corrigan ◽  
Morag Holdsworth ◽  
Fiona L. Henriquez ◽  
Andrew C. Ward
Keyword(s):  
Real Time ◽  
Electrochemical Sensors ◽  
Low Cost ◽  
Human Consumption ◽  
Complex Nature ◽  
Beta Lactam ◽  
Antibiotic Drugs ◽  
Antimicrobial Residues ◽  
Wide Range ◽  
Tetracycline Residues

Antimicrobial drug residues in food are strictly controlled and monitored by national laws in most territories. Tetracyclines are a major broad-spectrum antibiotic class, active against a wide range of Gram-positive and Gram-negative bacteria, and they are the leading choice for the treatment of many conditions in veterinary medicine in recent years. In dairy farms, milk from cows being treated with antibiotic drugs, such as tetracyclines, is considered unfit for human consumption. Contamination of the farm bulk tank with milk containing these residues presents a threat to confidence of supply and results in financial losses to farmers and dairy. Real-time monitoring of milk production for antimicrobial residues could reduce this risk and help to minimise the release of residues into the environment where they can cause reservoirs of antimicrobial resistance. In this article, we review the existing literature for the detection of tetracyclines in cow’s milk. Firstly, the complex nature of the milk matrix is described, and the test strategies in commercial use are outlined. Following this, emerging biosensors in the low-cost biosensors field are contrasted against each other, focusing upon electrochemical biosensors. Existing commercial tests that identify antimicrobial residues within milk are largely limited to beta-lactam detection, or non-specific detection of microbial inhibition, with tests specific to tetracycline residues less prevalent. Herein, we review a number of emerging electrochemical biosensor detection strategies for tetracyclines, which have the potential to close this gap and address the industry challenges associated with existing tests.

scholarly journals A rotationally focused flow (RFF) microfluidic biosensor by density difference for early-stage detectable diagnosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noori Kim ◽  
Kyungsup Han ◽  
Pei-Chen Su ◽  
Insup Kim ◽  
Yong-Jin Yoon
Keyword(s):  
Early Detection ◽  
Optical Sensors ◽  
Early Stage ◽  
Point Of Care ◽  
Low Cost ◽  
Ease Of Use ◽  
Wavelength Shift ◽  
Label Free ◽  
Protein Biomarkers ◽  
Microfluidic Biosensor

AbstractLabel-free optical biosensors have received tremendous attention in point-of-care testing, especially in the emerging pandemic, COVID-19, since they advance toward early-detection, rapid, real-time, ease-of-use, and low-cost paradigms. Protein biomarkers testings require less sample modification process compared to nucleic-acid biomarkers’. However, challenges always are in detecting low-concentration for early-stage diagnosis. Here we present a Rotationally Focused Flow (RFF) method to enhance sensitivity(wavelength shift) of label-free optical sensors by increasing the detection probability of protein-based molecules. The RFF is structured by adding a less-dense fluid to focus the target-fluid in a T-shaped microchannel. It is integrated with label-free silicon microring resonators interacting with biotin-streptavidin. The suggested mechanism has demonstrated 0.19 fM concentration detection along with a significant magnitudes sensitivity enhancement compared to single flow methods. Verified by both CFD simulations and fluorescent flow-experiments, this study provides a promising proof-of-concept platform for next-generation lab-on-a-chip bioanalytics such as ultrafast and early-detection of COVID-19.

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