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Hempston, David William. "Force detection in levitated optomechanics." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/418004/.
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The use of levitated optomechanical systems as force sensors is a growing field with great potential. This thesis presents a system that achieves a sensitivity of ≈ 10⁻²² N/√Hz by using on-resonance forces and an optically levitated nanoparticle in a gradient force trap. It is possible to reach pressures of 10⁻⁶ mbar and trap particles with diameters of 50 nm to 300 nm. The particle's motion is detected with a homodyne-like detection system that measures the phase difference in the scattered and un-scattered, divergent, light. With this system it was possible to detect the changes in the particle's motion due to the application of an external AC and DC electric fields. DC electric fields showed a shift in the average position of up to 100 nm and also a shift of the relevant oscillator frequency of up to 1500 Hz. Applying an AC electric field resulted in the particle's motion being driven at the AC frequency. On resonance the detected signal increased by a factor of 200 which helps to measure smaller changes in the particle's motion compared to the undriven signal. Using the AC driving it was possible to detect a particle with a charge of just 4 3 electrons. In addition to this, two vacuum sources were investigated, the first being an ablating source that generated particles directly in the chamber, and the second being a sonicating source that releases pre-made particles from a surface. The ablated source used a high power nano-second Neodymium-doped Yttrium aluminium garnet (Nd:YAG) laser that was able to remove material from a silicon wafer with a 200 nm layer of silicon dioxide. It was possible to trap a nanoparticle with a radius of 353 nm at atmosphere but there was a large thermal distribution in the particle sizes. The sonicating source had the advantage that the particle's size range could be known before hand and also the source could be very close to the trap site. An acoustic horn was developed that focused the energy down to a 3 mm radius surface. It was possible to see a large release of 100 nm particles, however, none of them were trapped. It was assumed that the particles were still too large to trap so steps were taken towards a MHz source. This resulted in the first detection of a particle from an ultrasonic source at the trap site. The signal didn't last long but this still holds promise as a source once a transducer or even a horn have been designed.
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Li, Sinan. "Laser speckle contrast detection of acoustic radiation force response." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/34931.
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Light and ultrasound are both non-ionizing radiations, ideal for biomedical applications. Recent studies on combining ultrasound and light for biomedical imaging show new promises in improving imaging quality and/or providing complementary imaging contrast. Among a variety of the imaging modalities that simultaneously use ultrasound and light, this work focuses on optical detection of tissue responses to acoustic radiation force (ARF). The applications include optical shear wave elastography and ultrasound modulated optical tomography. The first half of the thesis provides a systematic study on tracking shear waves in optical turbid media using CCD-based laser speckle contrast analysis. The theory, simulation and experiment are developed and cross-validated. The simulation quantitatively relates CCD speckle contrast signal with shear waves, providing useful information to understand the underlying physics. In addition, multiple shear waves are tracked using laser speckle contrast detection. Results show that two counter-propagating shear waves produce a modulation pattern in the optical signal, and the modulation pattern was suggested by simulation as a result of the dual shear wave interference. Shear wave speed measurements in phantoms suggest that the dual shear wave approach is more accurate than the single shear wave approach as that the standard deviation of the speed measurement is reduced by a factor of at least 2. The the dual shear wave approach also provides a reduced boundary effect. Both factors suggest that the dual shear wave approach should improve the accuracy of elasticity measurements. In the second half of the thesis, instead of detecting ARF response in the late phase, the study is motivated by detecting ARF response in the early stage for enhancement of ultrasound modulation of light. A pilot study on incorporating perfluorocarbon-based phase change contrast agent with ultrasound modulated optical tomography is explored. To understand the phase transition process, a quantitative measurement of acoustic nanodroplet vapourisation is developed. A preliminary result also showed that a single ultrasound burst can simultaneously vaporise the nanodroplets and sonify the converted microbubbles to provide additional ultrasound modulation of light. This additional light modulation was shown to increase the laser speckle contrast signal detected on a CCD camera.
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Olsen, Anita J. "Detection of Genetic Abnormalities Using High Speed Atomic Force Microscopy." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5428.
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Genetic mutations in the regulatory genes responsible for cell proliferation, differentiation, and death play a significant role in cancer. Molecular diagnostic and sequencing techniques used to detect these abnormalities have limitations that need to be overcome. These issues can be addressed with the use of a novel High-Speed Atomic Force Microscope (HS-AFM) taking physical measurement of molecules labeled with a programmable nanoparticle (Cas9). This technique was used to demonstrate proof-of-concept using genetic mutations found in breast cancer and follicular lymphoma.
Current quantification methods for copy number variation (gene duplication) and gene expression analysis are based on amplification and fluorescence-based techniques (e.g., qPCR and FISH). These methods cannot easily and reliably detect multiple targets in a single reaction and produce amplification errors in the detection of low abundance targets. These issues were overcome using a multiplex amplification with low cycles of polymerase chain reaction (PCR), followed by single-molecule detection with Atomic Force Microscopy (AFM). The gene expression proles of two different total human RNA samples from our single reaction multiplex PCR/AFM aligned with the data from individual singleplex quantitative PCR reactions. The conventional AFM was replaced by a HS-AFM, invented by collaborators from the University of Bristol, to demonstrate the throughput capabilities necessary for use in clinical applications. The sensitivity of this instrument was able to detect contamination in three out of four popular commercial DNA purification kits, proving our technique useful for optimizing assay conditions.
To further increase features of this technique and broaden its application, a `nanomapping' labeling technique was established for physical mapping of DNA using HS-AFM. This approach increases multiplexing capabilities and is a complementary method for sequencing and other physical mapping techniques. Commercially available DNA was used to determine the efficiency and precision of CRISPR Cas9 labeling and applied to clinical biopsies for the detection and precise mapping of BCL2-IGH translocations present in follicular lymphoma tumors. To reduce the size and cost of the HS-AFM, the detection component was replaced by DVD optics and produced images of similar size, resolution, and quality. The successful demonstration and evolution of this technique proves promising for clinical implementation.
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Ollander, Brooke. "Detection of Iron in Biological Samples Using Magnetic Force Microscopy." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492015770077109.
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Iams, Douglas Allan 1960. "Atomic force microscopy of magnetic samples using optical detection methods." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277163.
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An atomic force microscope is an instrument that is capable of imaging magnetic, electric and van der Waals forces with a very high resolution. In this thesis, different methods for detecting the displacement of the force sensing lever in such an atomic force microscope are discussed. Special emphasis is given to optical detection methods that are used in conjunction with a vibrating lever. The three optical systems that are discussed are based on (1) the heterodyne interferometer, (2) the homodyne interferometer, and (3) a new design that utilizes feedback into a laser diode. Images of a hard disk drive head and of domains in a TbFeCo thin film sample that were obtained with the heterodyne system are presented. Also presented are images of domains in a different TbFeCo sample and of interdigital fingers that were collected with the novel laser diode system.
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Van, Gorp Byron Everrett. "Force sensing integrated tip and active readout structures with improved dynamics and detection range." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22645.
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Koch, Sandra. "The detection of sharp force, blunt force and gunshot trauma on whole pigs recovered from a fire environment." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12455.
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Thesis (M.S.)--Boston University<br>The ability to recognize and identify skeletal material is a fundamental skill in forensic and physical anthropology. Understanding the process that remains have undergone when they have been exposed to a fire environment necessitates further study and specialization as the basic structure of a bone may be altered from the microscopic level to the overall morphology. Analysis of burnt bone goes beyond understanding how the normal taphonomic processes may affect skeletal remains to the specifics of heat and fire related changes. Additionally, the study of how heat or fire alteration affects trauma determinations can be important for determining the forensic significance of a case. The procedures of a fire investigation play a very important role in the recognition, preservation and analysis of skeletal remains especially considering site recovery techniques and perimortem trauma interpretation determination. This study utilized whole pigs to document changes to trauma from exposure to a compartment fire. The results were compared to previous studies done on individual skeletal elements to show that trauma was still recognizable and often protected in the postcranial body.
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Chabot, Michelle Diane. "Force detection of nuclear magnetic resonance using double-torsional micro-oscillators." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3025004.
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Zhang, Zelun. "User mobility detection using foot force sensors and mobile phone GPS." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9116.
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A user (or human) mobility context is defined as a type of user context that describes a type of whole body posture (e.g., standing versus sitting) and/or a type of travel or transportation mode (e.g., walking, cycling, travel by bus, etc). Such a context can be derived from low-level sensor data and spatial contexts, including location coordinates, 3D-orientation, direction (with respect to magnetic north), velocity and acceleration. Different value-added services can be adapted to users’ mobility contexts such as assessing how eco-friendly our travel is, and adapting travel information services such as maps to different transportation modes. Current sensor-based methods for user mobility detection have several key limitations: narrow range of recognition, coarse user mobility recognition capability, and low recognition accuracy. In this thesis, a new Foot-Force and GPS (FF+GPS) sensor method is proposed to overcome these challenges that leverages a set of wearable FF sensors in combination with mobile phone GPS. The novelty of this approach is that it provides a more comprehensive recognition capability in terms of reliably recognising various fine-grained human postures and transportation modes. In addition, by comparing the new FF+GPS method with both an accelerometer (ACC) method (62% accuracy) and an ACC+GPS based method (70% accuracy) as baseline methods, it obtains a higher accuracy (90%) with less computational complexity, when tested on a dataset obtained from ten individuals. In addition, the new FF+GPS method has been further extended and evaluated. More specifically, the trade-off between the computation and resources needed to support lower versus higher number of features and sensors has been investigated. The improved FF+GPS method reduced the number of classification features from 31 to 12, reduced the number of FF sensors from 8 to 4, and reduced the use of GPS in mobility activity recognition.
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Arora, Bhupinder S. "Detection of polysaccharides on a bacterial cell surface using Atomic Force Microscopy." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0826103-011111.
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Thesis (M.S.)--Worcester Polytechnic Institute.<br>Keywords: Leuconostoc mesenteroides NIRC1542; Atomic Force Microscope; Pseudomonas putida KT2442; Adhesion. Includes bibliographical references (p. 75-83).
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Leonard, Anthony. "Développement d'une technologie hybride à base de microbilles pour la détection d'anticorps IgE : vers le diagnostic d'allergies." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY061/document.
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Les allergies représentent un enjeu sociétal majeur dans nos sociétés modernes. Les outils de diagnostics actuels permettent la mesure de concentration d’anticorps spécifiques IgE responsables des réactions allergiques contenus dans le sérum de patient. L’intégration de nano-micro particules diminue les distances de diffusion permettant de miniaturiser les dispositifs, de diminuer le temps de réaction et d’améliorer l’efficacité du diagnostic. C’est dans cette perspective que cette thèse se positionne en développant une méthode innovante de détection des anticorps IgE par l’utilisation de microbilles polystyrènes 10µm (PS) et superparamagnétiques 1µm (SPM).L’idée explorée dans cette thèse est d’utiliser les microbilles PS comme support d’immunodosage et les propriétés magnétiques des microbilles SPM en réalisant un tri magnétique des microbilles PS. Nous avons développé cette technologie en trois étapes technologiques distinctes. Premièrement, la bio-fonctionnalisation a permis le greffage des allergènes et des anticorps à la surface des microbilles qui réagissent ensuite avec le sérum de patient. Puis, le tri magnétique a été développé pour isoler les microbilles PS en fonction de la présence ou non d’anticorps IgE à leur surface. L’efficacité de ce procédé est proportionnelle à la quantité d’IgE par microbilles. Finalement une technologie d’auto-assemblage de microbilles appelées « assemblage gravitationnel » a été développé en exploitant avantageusement les phénomènes de sédimentation et de capillarité. Il a été montré que cette technologie complémentaire à la technologie d’assemblage capillaire étend le domaine de l’assemblage à des systèmes de suspensions colloïdales denses. De plus, cette technologie permet d’atteindre une limite de détection de 2 microbilles/ml.Des tests cliniques ont été réalisés avec succès à partir de sérums de patient sensibles à l’arachide, à la noisette et à la crevette. Le temps de procédé, la limite de détection et la dynamique de détection ont été optimisés. La preuve de concept de détection des anticorps IgE a été présentée et ouvre la voie vers le diagnostic d’allergies multiplexe<br>Allergies represent a major social issue for modern societies. Current diagnostic tools enables to measure the concentration of specific IgE antibodies responsible for allergic response into the patient’s serum. The use of nano-micro particles decreases diffusion distances in order to shrink the size of device, reduce the length of time reaction and improve diagnostic efficiency. In this perspective, the PhD work develop an innovative method to detect IgE antibodies by using both 10µm polystyrene (PS) and 1µm superparamagnetic (SPM) microbeads.The PhD explores the idea of using both PS microbeads as support of immunoassay and magnetic properties of SPM microbeads in order to perform a magnetic sorting of PS microbeads. We have developped this technology in 3 different technological steps. First, biofunctionnalization is used to link allergens and antibodies onto the surface of microbeads intended to react with serum patient. Then, the magnetic sorting has been developped to isolate PS microbeads depending on the presence / absence of IgE antibodies onto their surface. The efficiency of such a process is proportional to IgE quantity per microbeads. Finally, a self-assembly process of microbeads called « gravitational assembly » has been developped by studying sedimentation and capillary phenomenon. It has been shown that this complementary technology to the capillary assembly technology extend the scope of assembly to dense system of colloidal suspension. I addition, this technology reaches a detection limit of 2 microbeads per ml.Clinical trials have been succesfully performed from serum patient allergic to peanut, hazelnut or shrimp. The process time, detection limit and dynamic range of the detection system have been studied and optimized. The proof of concept of IgE antibodies detection have been presented and points the way towards the multiplex diagnosis of allergies
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Hyttinen, Emil, Simon Nee, and Simon Ye. "Fundamental limits to force detection using a bulk mode resonator in liquid." Thesis, KTH, Fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103031.
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The basic idea of non-contact Atomic Force Microscopy (AFM) is to generate an image of a surface by scanning with a sharp probe on a sample, without touching. During the scan the reactions due to the non-contact forces between the tip of the probe and the surface are measured. There is interest in imaging biological samples with AFM, but conventional AFM cantilevers perform poorly in a liquid environment, which is required for many measurements in biology. The aim of this report is to find out if a crystal bulk mode resonator can be used as an alternative to a conventional cantilever in liquid. AFM measurements are limited by noise. To get sensitive measurements the noise needs to be minimized. However, the noise originates from random thermal motions, which will always be present at non-zero temperatures. The noise determines the fundamental limit of sensitivity for a certain resonator. Therefore we study the thermal noise from a crystal resonator when operating in a liquid environment. This is done by building a circuit that amplifies the noise signal from the resonator.<br>Idén bakom Atomic Force Microscopy (AFM) är att generera en bild av en yta genom att svepa en skarp prob över den utan kontakt. Medan man sveper över ytan mäter man reaktionskrafterna på proben från ytan. AFM-mätmetoder är intressanta för biologiska ändamål, men konventionella AFM-probar fungerar inte särskilt bra nedsänkta i vätska, vilket är en förutsättning för många mätningar inom biologin. Målet med denna rapport är att ta reda på ifall en longitudinellt oscillerande kvartskristallresonator kan användas som alternativ till en vanlig AFM-prob för mätningar i vätskemiljö. AFM mätningar begränsas av brus. För att få en känslig mätning måste bruset minimeras. Bruset härrör dock till större del från slumpmässig termisk rörelse kring oscillatorn, vilket inte kan elimineras. Detta brus bestämmer den fundamentala precisionsgränsen för en viss resonator. Därför kommer vi, i denna rapport, att studera bruset från en kristallresonator i vätskemiljö. Detta görs genom att bygga en elektrisk förstärkarkrets för att förstärka brussignalen från resonatorn.
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Weitzman, Robert C. "Statistical monitoring of police force for rapid detection of changes in frequency." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA374321.
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Thesis (M.S. in Operations Research) Naval Postgraduate School, December 1999.<br>"December 1999". Thesis advisor(s): David H. Olwell. Includes bibliographical references (p. 79-80). Also available online.
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Pesch, Alexander Hans. "Damage Detection of Rotors Using Magnetic Force Actuator: Analysis and Experimental Verification." Cleveland, Ohio : Cleveland State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1229016747.
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Thesis (M.S.)--Cleveland State University, 2008.<br>Abstract. Title from PDF t.p. (viewed on Mar. 17, 2009). Includes bibliographical references (p. 75-81) and appendices. Available online via the OhioLINK ETD Center. Also available in print.
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Mas, Soler Josep. "Investigation on force detection methods for optical trapping and sensing inside living cells." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/400485.
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Optical Tweezers (OT) are a light-based non-invasive tool that has played an important role during the last decades in the field of biophotonics, together with the advances in optical microscopy techniques. Optical trapping and micromanipulation of microscopic objects is nowadays possible with tightly focused laser beams, with the capability of measuring forces acting on the trapped particle in the order of piconewtons. OT have found numerous applications in the field of biophysics, and more specifically in molecular motor studies. One of the open challenges in the field is measuring molecular motor forces in their natural (in vivo) environment: the interior of living cells. Due to the complex mechanical properties of the cell cytoplasm, standard trap force calibration methods do not apply in this environment.
In this thesis we investigate two recent optical force calibration methods: active-passive calibration in viscoelastic media, and direct force measurements via light momentum changes. The two methods are tested and cross-validated inside living cells, and an application involving intracellular molecular motor stall force measurements is demonstrated. The obtained results prove the possibility of measuring forces inside the cell cytoplasm with holographic tweezers, even with an object-independent trap force calibration when the conditions for the momentum-based technique are fulfilled.
We also present an algorithm for manipulating groups of optical traps with minimal computational cost, using random mask multiplexing combined with iterative computer-generated holograms for dynamic holographic optical tweezers.<br>Les pinces òptiques són una tècnica no invasiva, basada en llum, que ha tingut un paper important en les últimes dècades en el camp de la biofotònica, en combinació amb les noves tècniques de microscòpia. L’atrapament i manipulació d’objectes microscòpics per mitjans òptics és avui en dia una possibilitat real, que permet no només desplaçar objectes, sinó també mesurar les forces que actuen sobre aquests. És per això que les trampes òptiques han trobat nombroses aplicacions en el camp de la biofísica, i més concretament, en l’estudi de motors moleculars. Un dels reptes pendents en aquest sentit és la mesura de força de motors moleculars en el seu entorn natural: l’interior de cèl·lules vives. Degut a la complexitat mecànica del citoplasma, els mètodes estàndard de calibratge de pinces òptiques no són vàlids en aquest entorn.
En aquesta tesi s’investiguen dos mètodes recents de mesura de força que tenen el potencial de ser utilitzats a l’interior cel·lular: la calibració activa-passiva de pinces òptiques en medis viscoelàstics, i la mesura força directa a través de canvis en el moment del feix de llum. Es demostra que els dos mètodes, basats en principis teòrics totalment diferents, donen resultats compatibles dins de cèl·lules, validant així la possibilitat de mesurar forces pinces òptiques a l’interior cel·lular de forma fiable. La utilitat pràctica del mètode de força directa, la constant de calibració del qual és independent de l’objecte atrapat, es demostra amb una aplicació concreta: la mesura de força de motors moleculars involucrats en el transport de vesícules en cèl·lules animals.
També presentem un algoritme per a la manipulació dinàmica de grups de trampes òptiques utilitzant holografia digital, amb un cost computacional mínim. S’utilitza el multiplexat espacial de màscares aleatòries, partint d’hologrames pre-generats amb mètodes iteratius, per experiments de manipulació a temps real.
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Logeeshan, Velmanickam. "Implementation of Low Cost, High-Throughput and High Sensitive Biomarker Detection Technique in Serum/Plasma Samples by Integrating Dielectrophoresis and Fluorescence Based Platform." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/29893.
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Low-cost, highly-sensitivity, and minimally invasive tests for the detection and monitoring of life-threatening cancers can reduce the worldwide disease burden. The disease diagnosis community is constantly working to improve the detection capabilities of the deadly cancers (e.g.: pancreatic and lung) at their early stages. Still there were many cancers cannot be detected at their early stages due to lack of early diagnosis techniques. One of the reason being, many cancers that occur in the body release minute amounts of biomarker molecules during the initial stages (e.g.: DNA, RNA, miRNA and antigens) in the body fluids such as blood and serum. Since the traditional bio-sensing techniques have reached their maximum capacity in terms of critical performance parameters (sensitivity, detection time, reproducibility and limit of detection) there is an urgent need for innovative approaches that can fill this gap.
To address this unmet need, here we report on developing a novel bio-sensing technique for detecting and quantifying biomolecules from the patients? plasma/serum samples at point-of-care settings. Here we have investigated the novel interactions between biomolecules and externally applied fields to effectively manipulate and specifically concentrate them at a certain detection spots near electrodes on the detection device. Then the near-field interactions between the fluorophores and the free electrons on metal surfaces were successfully integrated with the externally applied low frequency (<10MHz) electric field, to achieve maximum florescence enhancement, that produces the detection limit of target-biomolecules in the rage of femto molars (fM). Moreover, the externally applied electric potential produces dielectrophoretic and thermophoretic force on the biomolecules, together with these forces we were able to separate the fluorophore-labelled rare target-biomolecules from the others in a sample.
The novel integrated technique is tested and proved to be superior to the current gold standards (qRT-PCR and ELISA) for target-biomolecules detection in critical performance parameters. Finally the technique was used to analyze healthy and pancreatic cancer patients? samples and further it has been proved that we can differentiate the healthy individuals and cancer patients. In addition, this technique is being applied to the other diseases such as obesity, opioid addiction and other types of cancers.
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Petet, Thomas J. Jr. "Characterization of Poly(dimethylsiloxane) Blends and Fabrication of Soft Micropillar Arrays for Force Detection." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4649.
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Diseases involving fibrosis cause tens of thousands of deaths per year in the US alone. These diseases are characterized by a large amount of extracellular matrix, causing stiff abnormal tissues that may not function correctly. To take steps towards curing these diseases, a fundamental understanding of how cells interact with their substrate and how mechanical forces alter signaling pathways is vital. Studying the mechanobiology of cells and the interaction between a cell and its extracellular matrix can help explain the mechanisms behind stem cell differentiation, cell migration, and metastasis. Due to the correlation between force, extracellular matrix assembly, and substrate stiffness, it is vital to make in vitro models that more accurately simulate biological stiffness as well as measure the amount of force and extracellular matrix assembly. To accomplish this, blends of two types of poly(dimethylsiloxane) (PDMS) were made and the material properties of these polymer blends were characterized. A field of 5µm or 7µm microscopic pillars (referred to as posts) with a diameter of 2.2µm were fabricated from these blends. Each combination of PDMS blend and post height were calibrated and the stiffness was recorded. Additionally, polymer attachment experiments were run to ensure cells survived and had a normal phenotype on the different blends of PDMS when compared to pure PDMS. Finally, cells were placed onto a field of posts and their forces were calculated using the new stiffness found for each blend of post. Varying the PDMS material stiffness using blends allow posts to be much more physiologically relevant and help to create more accurate in vitro models while still allowing easy and accurate force measurement. More biologically relevant in vitro models can help us acquire more accurate results when testing new drugs or examining new signaling pathways.
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Hida, H., M. Shikida, K. Fukuzawa, et al. "Development of Self-Vibration and -Detection AFM Probe by using Quartz Tuning Fork." IEEE, 2007. http://hdl.handle.net/2237/9564.
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Travaglini, Lorenzo. "In-situ detection of defect formation in organic flexible electronics by Kelvin Probe Force Microscopy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10380/.
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Organic semiconductor technology has attracted considerable research interest in view of its great promise for large area, lightweight, and flexible electronics applications. Owing to their advantages in processing and unique physical properties, organic semiconductors can bring exciting new opportunities for broad-impact applications requiring large area coverage, mechanical flexibility, low-temperature processing, and low cost. In order to achieve highly flexible device architecture it is crucial to understand on a microscopic scale how mechanical deformation affects the electrical performance of organic thin film devices. Towards this aim, I established in this thesis the experimental technique of Kelvin Probe Force Microscopy (KPFM) as a tool to investigate the morphology and the surface potential of organic semiconducting thin films under mechanical strain.
KPFM has been employed to investigate the strain response of two different Organic Thin Film Transistor with active layer made by 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-Pentacene), and Poly(3-hexylthiophene-2,5-diyl) (P3HT). The results show that this technique allows to investigate on a microscopic scale failure of flexible TFT with this kind of materials during bending. I find that the abrupt reduction of TIPS-pentacene device performance at critical bending radii is related to the formation of nano-cracks in the microcrystal morphology, easily identified due to the abrupt variation in surface potential caused by local increase in resistance. Numerical simulation of the bending mechanics of the transistor structure further identifies the mechanical strain exerted on the TIPS-pentacene micro-crystals as the fundamental origin of fracture.
Instead for P3HT based transistors no significant reduction in electrical performance is observed during bending. This finding is attributed to the amorphous nature of the polymer giving rise to an elastic response without the occurrence of crack formation.
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MacNeill, Olivia Lee. "Contribution of biomechanical measurements to detection of toxicity in vitro : an atomic force microscope study." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28414.
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The liver has a wide range of capabilities and is the key organ for drug metabolism, detoxification and elimination. Molecules are absorbed from the GI tract into the bloodstream and transported to the liver through the portal vein circulation system. Most of the metabolic functions within the liver are processed by hepatocytes. The project aim was to test two drugs (5-Fluorouracil (5-FU) and diclofenac) with different metabolic pathways, interpret their toxic effects in hepatocytes and relate these to mechanical and morphological alterations in the cells. The findings of this project thereby allow development of a cell mechanics model for toxicity profiling and drug efficacy at a subcellular level. Hepatocellular carcinoma (HCC) is the second most common cancer in the world and the most frequent type of liver cancer. Therefore, a great amount of effort has been aimed at the discovery of anticancer compounds to treat it. The majority of conventional chemotherapeutic drugs work on the principle of halting DNA synthesis, and 5-FU follows this principle. This drug is also commonly used for treatment for most gastrointestinal tract cancers. When 5-FU is administered, the toxic adverse effects need to be considered as there is a possibility of severe side effects. To characterise toxic changes in hepatocytes, an Atomic Force Microscope (AFM) was used, which can produce high-resolution images by probing the surface of the cell, to provide information on the cell’s mechanical properties (such as Young’s modulus). However, with the complexity of this technique it has proved to be challenging to measure relative Young’s modulus values that minimise artefacts which affected the image quality of the cells. Using 5-FU as a model drug, apoptosis was detected by relating surface morphology and mechanical measurements. The surface morphology of HepG2 cells was examined with AFM, and the images produced showed cells exhibiting networking lines of a fibrous nature on the cell surface and protrusions from the cell membrane after the application of 5-FU. This is thought to be related to apoptotic behaviour occurring within the cell but this is not conclusive and further investigations need to be conducted. Mitochondria are the main source of adenosine triphosphate (ATP), which is vital for energy, and therefore control all active processes within the cell. Mitochondrial injury often occurs due to drug toxicity, causing altered metabolic function within the cells. Diclofenac is a widely prescribed NSAID, which may cause serious hepatotoxicity, and is thought to be a mitochondrial toxicant. When altering the physiological conditions from glucose containing medium to galactose containing medium, it was shown that the growth and metabolic function of HepG2 cells decreased. Diclofenac caused a depletion of ATP within the cells. When imaging the cell with AFM, after treatment with diclofenac, there were alterations at surface of HepG2 cells. When the cantilever was separated from the cell surface, the retraction curves showed intermolecular interactions occurring, after treatment with diclofenac which were not observed if the cells were untreated. Microscopic evidence suggested apoptosis may have occurred and it is proposed that the changes in the cell surface reflect this. Liposomes consisting of lipid bilayers can encapsulate a wide range of drugs, and their behaviour can be controlled by modifying their surface properties. This research also studied the production of liposomes in order to understand their interaction with cells. Liposomal delivery systems are used to improve the bioavailability of drugs and can reduce toxic effects. The liposomes were shown to engage with the cell surface by use of AFM but did not influence the cells viability, suggesting that they had potential as a non-toxic delivery system. This thesis has produced initial data to suggest that changes in cell mechanical properties can be used to detect changes in cell behaviour, such as apoptosis, but the method is still fraught with complexity.
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White, Shane Paul White. "Study of Heavy Metal/Ferromagnetic Films Using Electrical Detection and Local Ferromagnetic Resonance Force Microscopy." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524172007784423.
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Mills, Clayton Harry. "Movement and Force Measurement Systems as a Foundation for Biomimetic Research on Insects." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/2895.
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During the undertaken research and development, two major systems were designed. These were; a prototype force sensor, and a movement measurement system. Both the developed systems were designed for the intended field of insect research, but were developed using very different underlying principles. The force measurement system uses the piezo-electric effect induced in piezo-electric bimorph elements to produce a measure of force exerted on the sensor. The movement measurement system on the other hand uses computer vision (CV) techniques to find and track the three dimensional (3D) position of markers on the insect, and thereby record the pose of the insect.
To further increase the usefulness of the two measurement systems, a prototype graphical user interface (GUI) was produced to encapsulate the functionality of the systems and provide an end user with a more complete and functional research tool. The GUI allows a user to easily define the parameters required for the CV operations and presents the results of these operations to the user in an easily understood visual format. The GUI is also intended to display force measurements in a graphical means to make them easily interpreted. The GUI has been named Weta Evaluation Tracking and Analysis (WETA).
Testing on the developed prototype force sensor shows that the piezo-electric bimorph elements provide an adequate measure of force exerted on them, when the voltage signal produced by an element is integrated. Furthermore, the testing showed that the developed force sensor layout produces an adequate measure of forces in the two horizontal linear degrees of freedom (DOF), but the prototype did not produce a good measure of forces
in the vertical linear DOF.
Development and testing of the movement measurement system showed that stereo vision techniques have the ability to produce accurate measurements of 3D position using two cameras. Although, when testing these techniques with one of the cameras replaced by a mirror, the system produced less than satisfactory results. Further testing on the feature detection and tracking portions of the movement system showed that even though these systems were implemented in a relatively simple way, they were still adequate in their associated operations. However, it was found that with some simple changes in colour spaces used during feature detection, the performance of the feature detection system in varying illumination was greatly improved. The tracking system on the other hand, operated adequately using just its associated basic principles.
During the development of both prototype measurement systems, a number of conclusions were formulated that indicated areas of future development. These areas include; advanced force sensor configurations, force sensor miniaturisation, design of a force plate, improvement of feature detection and tracking, and refining of the stereo vision equipment.
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Cundy, Michael E. "Detection and measurement of density fluctuations induced by a magnetohydrodynamic force in a supersonic boundary layer." Connect to this title online, 2005. http://hdl.handle.net/1811/273.
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Thesis (Honors)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains 29 p.; also includes graphics (some col.). This research has been supported by the AFOSR under grant F49620-02-1-0164, Phase II SBIR grant F33615-01-C-3112 of Air Vehicles Directorate of AFRL, and by the National Science Foundation (NSF) Division of Plasma Physics. Available online via Ohio State University's Knowledge Bank. Includes bibliographical references (p. 29). Available online via Ohio State University's Knowledge Bank.
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Papastathis, Ioannis. "Intention Detection and Arm Kinematic Control in Soft Robotic Medical Assistive Device." Thesis, KTH, Skolan för teknik och hälsa (STH), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173499.
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Aging in humans is often associated with reduced muscle strength and difficulty in elevating the arm and sustaining it at a certain position. The aim of this master thesis is to propose a number of technical solutions integrated into a complete electronic system which can be used to support the user's muscle capacity and partially resist gravitational load. An electronic system consisting of sensors, a control unit and an actuator has been developed. The system is able to detect the user's motion intention based on an angle detection algorithm and perform kinematic control over the user's arm by adjusting the level of support at different degrees of elevation. A force control algorithm has been developed for controlling the actuating mechanism, providing the user with a natural and intuitive support during arm elevation. The implemented system is a first step towards the development of a medical assistive device for the elderly or patients with reduced muscle strength allowing them to independently perform a number of personal activities of daily life where active participation of the upper limb is required.
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Loper, Thomas Cameron. "A candidate functional architecture design for the detection and monitoring process of a counterdrug joint task force." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA272515.
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Thesis (M.S. in Systems Technology) Naval Postgraduate School, June 1993.<br>Thesis advisor(s): Jones, Carl R. ; Sengupta, Kishore. "June 1993." Includes bibliographical references. Also available online.
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Ruane, William Terrence. "Controllable Spin Wave Generation with Spatially Dependent Magnetic Fields and Their Detection Using Ferromagnetic Resonance Force Microscopy." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524171463673634.
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Ospina, Triviño Andrés Felipe. "Intrinsic tactile sensing system for robotic dexterous manipulation." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066369/document.
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La détection tactile et la détection de glissement jouent un rôle important en permettant la manipulation robotique dextre des objets. Ainsi, le développement d'un système de capteur tactile entièrement intégré à haute résolution présente un intérêt certain. Ces travaux traitent de la conception et de la mise en place d'un système tactile intrinsèque basé sur un ensemble de capteurs MEMs de force à 3 axes et la détection du glissement avec ce système. Afin de créer un système tactile, les capteurs de force à 3 axes sont protégés par un revêtement, une étude sur le revêtement est réalisée. Deux systèmes intrinsèques différents basés sur un ensemble de capteurs de force à 3 axes sont développés, le premier est utilisé comme test de faisabilité de ce type de système. Le deuxième système intrinsèque est adapté à un doigt robotique à surface souple. Les systèmes proposés mesurent trois composants de force, le couple normal à la surface de contact et la position du centre de contact appliqué sur sa surface sensible. Les deux systèmes sont caractérisés et testés. La détection du glissement avec un système tactile intrinsèque est testée également. La détection du glissement est faite par l'application de la théorie de la surface limite et du modèle de contact viscoélastique<br>Tactile sensing and slip detection plays an important role in enabling robotic dexterous object manipulation. Thus developing a high-resolution fully integrated tactile sensor system is of great interest. This work deals the design and implementation of an intrinsic tactile sensing system based on a set of 3-axis force MEMs sensors and the detection of slippage with such system. In order to create a tactile system the 3-axis force sensors are protected by a coating, a study about the coating is made. Two different intrinsic systems based on an array of 3-axis force sensors are developed, the first one is used a feasibility test of this kind of system. The second intrinsic system is adapted to a robotic finger with soft surface. The proposed systems measures three-force components, the normal torque to the contact surface, and the position of the contact centroid applied to its sensitive surface. Both systems are characterized and tested. The detection of slippage with an intrinsic tactile system is tested. The application of the limit surface theory and the viscoelastic model of contact make the detection of slippage
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Cardellino, Jeremy D. "Dynamics of Paramagnetic Spins: A Study of Spin Defects using Magnetic Resonance Force Microscopy." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448982765.
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Zytnicki, Daniel. "La sensibilite dynamique des organes tendineux de golgi et son role dans la detection des variations de la force contractile." Paris 6, 1989. http://www.theses.fr/1989PA066534.
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Les organes tendineux de golgi, mecanorecepteurs de la proprioception musculaire des mammiferes, sont specifiquement sensibles a la contraction et non pas a l'etirement du muscle. Chaque organe tendineux est active par la contraction d'un petit groupe d'unites motrices dites en serie. Le but des experiences rapportees dans ce travail, realisees dans les muscles peroniers de chats anesthesies au nembutal, etait d'examiner comment les organes tendineux signalent les contractions non-fusionnees de leurs unites motrices en-serie. Au cours de cette etude, nous avons mis en evidence une propriete fonctionnelle importante, jusque-la meconnue, des organes tendineux: leur grande sensibilite aux composantes dynamiques des contractions, qui les rend beaucoup plus sensibles aux variations de la force contractile qu'a son niveau moyen. Cette sensibilite dynamique se manifeste aussi bien lorsque la force contractile se developpe en condition isometrique, que pendant un raccourcissement du muscle; elle persiste lorsque plusieurs unites motrices sont stimulees ensemble. La decharge d'un organe tendineux signale bien les variations de la force contractile, si petites soient-elles, mais ne contient pas d'information concernant leur amplitude ou le niveau global de la force. Dans son ensemble, la population des organes tendineux d'un muscle se comporte comme un capteur privilegiant les parametres dynamiques de la force. Lorsque plusieurs unites motrices sont stimulees simultanement, le message de variation de force est toujours present dans l'ensemble des decharges des organes tendineux, mais la sommation des effets produits par chaque unite motrice n'est pas lineaire. Les influx afferents des organes tendineux informant donc de facon privilegiee le systeme nerveux central des fluctuations rapides de la force musculaire, ce qui suggere qu'il s'agit la d'informations significatives pour l'exercice du controle moteur
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Fernandez, Rodriguez Rodolfo. "Confined Mesoscopic Fluid-like Films Analyzed with Frequency Modulation and Acoustic Detection." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2047.
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Complete understanding of the physics underlying the changes in viscoelasticity, relaxation time, and phase transitions that mesoscopic fluid-like systems undergo at solid-liquid interfaces or under confinement remains one of the major challenges in condensed matter physics. Moreover, studies of confined mesoscopic fluid films are relevant to technological areas like adhesion, wetting processes and nanotribology.
This thesis addresses the interaction between two sliding solids interfaces separated by a nanometer sized gap, with emphasis on the role of the mesoscopic fluid film trapped between them. For this purpose we integrated two acoustic techniques, recently introduced by our group, into a sub-nanometer precision and thermal drift corrected scanning probe microscope (SPM): the shear-force/acoustic near-field Microscope (SANM) and the whispering gallery acoustic sensing (WGAS). The SANM monitors the sound waves originating in the probe-layer interaction while the motion of the probe is monitored by the WGAS. Additionally, we decouple the interaction forces by using frequency modulation and measure the local tunneling current to help establish the location of the substrate. Our results show a strong correlation between the elastic component of the probe's interaction and the SANM amplitude, as well as between the phase lag response of the fluid relative to the probe's excitation (represented by the SANM phase) and the onset of the probe-sample contact region. Frequency modulation SANM-WGAS brings a new acoustic sensing mechanism to the challenging characterization of fluid-like physical systems at the nanometer scale.
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Clark, Matthew Taylor. "The driven and stochastic dynamics of micro and nanoscale cantilevers in viscous fluid and near a solid boundary." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29411.
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Micro and nanoscale systems are rapidly evolving to improve the resolution of experimental measurements. Experiments involving such small scale devices are difficult and expensive, and the available analytical theory to describe their dynamics is idealized. The dynamics of microscopic cantilevers in fluid are complicated and include significant contributions from many sources in an actual experiment. Some examples are: complex cantilever geometries, near-wall effects, thermal and external actuation techniques, and a variety of measurement techniques. Numerical simulations are a powerful approach to describe the dynamics of micro and nanoscale systems for the precise conditions of experiment. This thesis provides a numerical approach capable of addressing these inherent challenges and quantifies the dynamics of microscopic cantilevers in fluid for experimentally relevant conditions.
A thermodynamic approach based upon the fluctuation-dissipation theorem allows for the calculation of stochastic dynamics from deterministic dynamics. Using numerical simulations, the thermal motion can be described for the precise conditions of experiment. It is found that the measured dynamics of cantilevers differs depending on the quantity being measured. In particular, the dynamics of displacement and angle of the cantilever tip distribute energy differently to the higher flexural modes. The externally driven dynamics of microscale cantilevers in fluid are also considered. The driven dynamics are calculated using numerical simulations of the cantilever response to a force impulse. It is found that the driven dynamics depend upon the type of actuation in addition to the quantity measured. A comparison of the driven dynamics to the corresponding stochastic dynamics yields insight into the nature of the Brownian force acting on the cantilever.
Another experimentally relevant condition is the use of cantilevers with V-shaped planforms in fluid. The resulting flow field is three-dimensional and complex in contrast to what is found for a long and slender rectangular cantilever. Despite the flow complexity, the stochastic and driven dynamics of the fundamental mode can be predicted using a two-dimensional model with an appropriately chosen length scale. An experimentally motivated magnetomotive actuation technique is investigated. Results show that this approach generates power spectra nearly equivalent to the noise spectra. Furthermore, the case of a V-shaped cantilever in fluid and oscillating in proximity of a solid boundary is investigated. In the presence of a solid surface the fluid damping and added mass of fluid on the cantilever are larger than for a cantilever far from boundaries. This results in a lower frequency and quality factor for the fundamental resonance. This can impede experimental efforts because broad peaks lack distinct features that can be used to identify experimental signals.
An option to overcome the large viscous damping is to take advantage of higher modes of cantilever oscillation. The higher frequency oscillations of the higher modes generate a smaller viscous boundary layer and have a reduced added mass. As a result, the quality factor increases with increasing mode number. The frequency dependence of the fluid dynamics around a fluctuating microscale cantilever is also studied. The mass of fluid entrained by the cantilever and the viscous damping quantify the interaction of a cantilever with the surrounding fluid and are computed. Analytical expressions for these parameters are derived for moderate mode number. The techniques and findings of this thesis have broad applicability to a wide range of micro and nanotechnologies that rely upon understanding the dynamics of small scale structures in fluid.<br>Ph. D.
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Fong, Kin Chung. "High Sensitivity Electron Spin Resonance by Magnetic Resonance Force Microscopy at Low Temperature." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228338129.
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Piazzon, Nelly. "Characterization and detection of traces of energetic materials by Nanocalorimetry." Phd thesis, Université de Haute Alsace - Mulhouse, 2010. http://tel.archives-ouvertes.fr/tel-00702242.
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Calorimetry is one of the main techniques of thermal analysis. Most of physical or chemical modifications of material are associated with thermal effects whereby heat is absorbed (i.e., melting) or released (i.e., thermal decomposition). Typically, calorimetric experiments are performed with Differential Scanning Calorimetry (DSC), which measures the heat flux absorbed or released by the sample following the same temperature program as a reference material. In these experiments, measurements are typically carried out on a few milligrams of sample. However, for many applications one has to handle nanograms or even picograms of sample. One of such applications is relevant to studies of materials which can release a significant amount of energy during their decomposition (energetic materials). Calorimetry able to handle nanograms of sample could find potential applications in the field of explosives detection. Nanocalorimetry allows to heat small amounts of sample (a few nanograms to a few hundred picograms) at extreme heating rates, i.e. up to one million °C/s. The temperature increase can initiate several phenomena in energetic materials, therefore the calorimetry could be an appropriate technique to characterize and to detect energetic materials. The energetic materials used in this study are nitrocellulose (NC), hexogen (RDX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-ltexaazaisowurtzitane (CL-20) and penthrite (PETN). The manuscript presents our results on the nanocalorimeter calibration, on the thermal behaviour of the explosives studied with nanocalorimetry and also includes an evaluation of nanocalorimetry as a tool for explosives detection.
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Yucel, Mustafa Can. "Structural Identification, Damage Detection By Non-destructive Tests And Determining Axial Loads In Cables." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611278/index.pdf.
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Damage and condition identi&<br>#64257<br>cation of existing structures using non-destructive tests is a
common challenge that has been worked on for a long time. In this study, two di&<br>#64256<br>erent methods were developed to &<br>#64257<br>nd existing force on cables as well as determine bending characteristics (EI coe&<br>#64259<br>cients) of beam like structures (such as bridges). Comparing forces in symmetrically placed cables or against values obtained from design drawings would indicate structural
imbalance as well as &<br>#64257<br>nding EI coe&<br>#64259<br>cients at a number of segments on a bridge girder might
indicate weak regions that might possibly have undergone structural damage, having weak
connections, lost composite action etc. With the help of the proposed algorithm, the sti&<br>#64256<br>ness
parameters of bridges can be assessed and the location of any damage that is in the magnitude
which can a&<br>#64256<br>ect displacement behavior of system can be located. The developed methods are
demonstrated using the values analytically obtained from the created models and the e&<br>#64256<br>ectiveness of the algorithm is criticized. Furthermore, several damage scenarios on a scaled lab beam was used to test the application using real experimental data<br>including tests on undamaged beam (for identi&<br>#64257<br>cation) and tests on the damaged beam. Additional experiments were
conducted on a cable stretched in the laboratory instrumented using a load cell to measure
instantaneous axial load on the cable and compare these values against the values obtained from the developed tension measurement device. The results are compared and conclusions
are derived.
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Silga, Matthias. "Elaboration de monocristaux de hgi::(2) alpha par la methode du flux force : application a la detection de rayonnements X gamma et alpha." Clermont-Ferrand 2, 1986. http://www.theses.fr/1986CLF21009.
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Elaboration de monocristaux hg1::(2)-alpha en vue de leur utilisation comme detecteurs de rayonnements. La purification du materiau de base, le controle du transport de matiere, le controle de la sursaturation a l'interieur des ampoules de croissance, la monogermination et l'etude de la morphologie du cristal sont traites en relation avec les proprietes de detection. Une approche theorique par simulation monte-carlo de la reponse d'un detecteur hgi::(2) a ete faite
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Aktasoglu, Seyfullah. "Damage Detection In Beam-like Structures Via Combined Genetic Algorithm And Non-linear Optimisation." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614115/index.pdf.
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In this study, a combined genetic algorithm and non-linear optimisation system is designed and used in the identification of structural damage of a cantilever isotropic beam regarding its location and severity. The vibration-based features, both natural frequencies (i.e. eigenvalues) and displacement mode shapes (i.e. eigenvectors) of the structure in the first two out of plane bending modes, are selected as damage features for various types of damage comprising saw-cut and impact. For this purpose, commercial finite element modelling (FEM) and analysis software Msc. Patran/Nastran®<br>is used to obtain the aforementioned features from intact and damaged structures. Various damage scenarios are obtained regarding saw-cut type damage which is modelled as change in the element thicknesses and impact type damage which is modelled as a reduction of the elastic modulus of the elements in the finite element models. These models are generated by using both 1-D bar elements and 2-D shell type elements in Msc. Patran®<br>and then normal mode analyses are performed in order to extract element stiffness and mass matrices by using Msc. Nastran®<br>. Sensitivity matrices are then created by changing the related properties (i.e. reduction in elastic modulus and thickness) of the individual elements via successive normal mode analyses. The obtained sensitivity matrices are used as coefficients of element stiffness and/or mass matrices to construct global stiffness and/or mass matrices respectively. Following this, the residual force vectors obtained for different damage scenarios are minimised via a combined genetic algorithm and non-linear optimisation system to identify damage location and severity. This minimisation procedure is performed in two steps. First, the algorithm tries to minimise residual force vector (RFV) by only changing element stiffness matrices by aiming to detect impact type damage, as elastic modulus change is directly related to stiffness matrix. Secondly, it performs a minimisation over RFV by changing both element stiffness and mass matrices which aims to detect saw-cut type damage where thickness change is a function of both stiffness and mass matrices. The prediction of the damage type is then made by comparing the objective function value of these two steps. The lowest value (i.e. the fittest) indicates the damage type. The results of the minimisation also provide value of intactness where one representing intact and any value lower than one representing damage severity. The element related to that particular intactness value indicates the location of the damage on the structure. In case of having intactness values which are lower than one in value at various locations shows the existence of multi damage cases and provides their corresponding severities. The performance of the proposed combined genetic algorithm and non-linear optimisation system is tested on various damage scenarios created at different locations with different severities for both single and multi damage cases. The results indicate that the method used in this study is an effective one in the determination of type, severity and location of the damage in beam-like structures.
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Karlas, Thomas, Arne Dietrich, Veronica Peter, et al. "Evaluation of transient elastography, acoustic radiation force impulse imaging (ARFI), and enhanced liver function (ELF) score for detection of fibrosis in morbidly obese patients." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189067.
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Background: Liver fibrosis induced by non-alcoholic fatty liver disease causes peri-interventional complications in morbidly obese patients. We determined the performance of transient elastography (TE), acoustic radiation force impulse (ARFI) imaging, and enhanced liver fibrosis (ELF) score for fibrosis detection in bariatric patients.
Patients and Methods: 41 patients (median BMI 47 kg/m2) underwent 14-day low-energy diets to improve conditions prior to bariatric surgery (day 0). TE (M and XL probe), ARFI, and ELF score were performed
on days -15 and -1 and compared with intraoperative liver biopsies (NAS staging).
Results: Valid TE and ARFI results at day -15 and -1 were obtained in 49%/88%and 51%/90%of cases, respectively. High skin-to-liver-capsule distances correlated with invalid TE measurements. Fibrosis of liver biopsies was staged as F1 and F3 in n = 40 and n = 1 individuals.
However, variations (median/range at d-15/-1) of TE (4.6/2.6–75 and 6.7/2.9–21.3 kPa) and ARFI (2.1/0.7–3.7 and 2.0/0.7–3.8 m/s) were high and associated with overestimation of fibrosis. The ELF score correctly classified 87.5%of patients.
Conclusion: In bariatric patients, performance of TE and ARFI was poor and did not improve after weight loss. The ELF score correctly classified the majority of cases and should be further evaluated.
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Bodensiek, Kai [Verfasser], Iwan [Akademischer Betreuer] Schaap, and Andreas [Akademischer Betreuer] Janshoff. "Combining force and fluorescence microscopy for the manipulation and detection of single cells, viruses, and proteins / Kai Bodensiek. Gutachter: Iwan Schaap ; Andreas Janshoff. Betreuer: Iwan Schaap." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1059570084/34.
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Viljoen, Suretha. "Analysis of crosstalk signals in a cylindrical layered volume conductor influence of the anatomy, detection system and physical properties of the tissues /." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-08082005-113739.
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Scozzaro, Nicolas Joseph. "Ultrasensitive Measurements of Magnetism in Carbon-based Materials." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu148059474280115.
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Ibrahim, Amal. "Caractérisation de petits ions, de (bio)macromolécules et de nanoparticules par les méthodes électrophorétiques : charge effective et dépendance de la mobilité électrophorétique en force ionique." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20062/document.
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L'objectif principal de cette thèse a été d'étudier et de développer les méthodes électrophorétiques pour la détermination de la charge effective de petits ions, de (bio)macromolécules et de nanoparticules. En effet, la charge effective est un paramètre physico-chimique qui contrôle les interactions électrostatiques et qui permet d'accéder aux taux de condensation des contre-ions dans le cas de polyélectrolytes. Dans une première partie, différents modèles sur la mobilité électrophorétique (Nernst-Einstein, O'Brien-White-Ohshima, Yoon-Kim) ont été comparés pour la détermination de la charge effective à partir des valeurs expérimentales de mobilité électrophorétique et de rayon hydrodynamique. Trois autres méthodes expérimentales basées sur la sensibilité de détection UV en mode indirect, sur la sensibilité de détection en conductimétrie et sur la longueur des zones isotachophorétiques ont été étudiées. Ces méthodes ont été appliquées en particulier à la détermination de la charge effective de dendrimères greffés de la lysine et de polymères utilisés en délivrance de principe actif.Une étude du comportement électrophorétique en fonction de la force ionique nous a mené à proposer une représentation graphique, appelée « slope-plot », permettant de distinguer les solutés en fonction de leur nature (petits ions, polyélectrolytes, nanoparticules). Cette représentation peut s'avérer très utile pour l'optimisation des séparations en électrophorèse capillaire en fonction de la force ionique<br>The main objective of this thesis was to study and develop electrophoretic methods for effective charge determination of small ions, (bio)macromolecules and nanoparticles. Effective charge is a physical parameter that controls the electrostatic interactions and allows for the determination of condensed counter-ion fraction in the case of polyelectrolytes. In a first part, different models of electrophoretic mobility (Nernst-Einstein, O'Brien-White-Ohshima, Yoon-Kim) have been compared for effective charge determination from experimental values of electrophoretic mobility and hydrodynamic radius. Three other experimental methods based on the sensitivity of UV detection in indirect mode and in conductivity detection, or on the length of the isotachophoretic zones, were studied. These methods were applied to effective charge determination of dendrigraft poly-L-lysines and on drug delivery polymeric systems. A study of the ionic strength dependence of the electrophoretic mobility leads us to propose a graphical representation, called the slope-plot, allowing for the distinction between solutes according to their nature (small ions, polyelectrolytes, nanopaticles). The slop-plot can also be used for the optimization of electrophoretic separations according to the ionic strength
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Ngwanya, Olwethu. "Molecularly imprinted polymers for detection of volatile organics associated with fuel combustion." University of the Western Cape, 2018. http://hdl.handle.net/11394/6363.
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Magister Scientiae - MSc (Chemistry)<br>Pollutants such as polycyclic aromatic hydrocarbons (PAHs) are known for their toxic effects
which may lead to the cause of degenerative diseases in both humans and animals. PAHs are
widespread in the environment, and may be found in water, food, automotive industry and
petrochemical industries to name but a few sources. Literature reports have highlighted industrial
workplace exposure to PAHs as a leading cause for development of cancer in workers.
Particularly, workers in the petrochemical industry are adversely affected and the incidence of
skin and lung cancer in this population group is high.
The United States of America in its guidelines developed by environmental protection agency
(EPA) has identified 18 PAHs as priority pollutants. Among these are anthracene,
benzo[a]pyrene and pyrene which have been selected as the focal point of this study due to their
significance in the petrochemical industry.
Due to the carcinogenic and mutagenic properties reported in literature for certain PAHs, there
have been monitoring procedures taken in most countries around the world. The commonly used
analytical methods for the detection of PAHs from industrial samples are high performance
liquid chromatography (HPLC) coupled to fluorescence detection, membrane filtration,
ozonation and reverse osmosis. Analysis of PAHs from the petrochemical industry is typically
performed by HPLC method as well as sono-degredation in the presence of oxygen and
hydrogen peroxide.
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Aykan, Murat. "Identification Of Localized Nonlinearity For Dynamic Analysis Of Structures." Phd thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615596/index.pdf.
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Most engineering structures include nonlinearity to some degree. Depending on the dynamic conditions and level of external forcing, sometimes a linear structure assumption may be justified. However, design requirements of sophisticated structures such as satellites, stabilized weapon systems and radars may require nonlinear behavior to be considered for better performance. Therefore, it is very important to successfully detect, localize and parametrically identify nonlinearity in such cases. In engineering applications, the location of nonlinearity and its type may not be always known in advance. Furthermore, as the structure will be excited from only a few coordinates, the frequency response function matrices will not be complete. In order to parametrically identify more than one type of nonlinearity which may co-exist at the same location with the above mentioned limitations, a method is proposed where restoring force surface plots are used which are evaluated by describing function inversion. Then, by reformulating this method, a second method is proposed which can directly evaluate the total describing function of more than one type of nonlinearity which may co-exist at the same location without using any linear frequency response function matrix. It is also aimed in this study to use the nonlinearity localization formulations for damage localization purposes. The validation of the methods developed in this study is demonstrated with case studies based on simulated experiments, as well as real experiments with nonlinear structures and it is concluded that the methods are very promising to be used in engineering structures.
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Idrisoglu, Alper. "Wireless Sensor System for Monitoring Sportsmen Exposed to Hazardous Concussions." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18477.
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Sport-related Traumatic Brain injuries (TBI) are a major problem in ice hockey. Reports show that it occurs 160 concussion per 1000 hours of play time and 4.6% of head injuries leads to a concussion in Sweden. A system that can monitor the players in real time and indicate an impact can contribute to better understanding the biomechanical etiology of a concussion. Purpose of this project is to test the ability of a wireless sensor network for monitoring the g-Forces that affect the head of the ice hockey players in real-time. We build a wireless sensor network system called g-Force Monitoring System (GFMS) by implementing a Web Socket connection between the sensor nodes and the server. The sensor measures and transmits the data over the Web Socket protocol to the server and the server registers and allows monitoring of the g-Force values in real-time. We achieved a 6 ms sampling rate by using the g-Force Monitoring System. The system was able to operate during one hour play time without any significant problem. The stored data shows that the GFMS has an ability to indicate impact and its duration over a predefined threshold. The user of the system can monitor the g-Force data in real time or can do analyzes on stored values. The GFMS can deliver valuable indications. If the system can come to existence and be implemented into the ice hockey helmets, by letting medical experts to look at and analyze the g-Force data, it can decrease the diagnosis and recovery time of a concussion. It can help to make the Ice hockey arena to a safer place without having to change the rhythm of the game.
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Accadia, Timothée. "Vérification de la reconstruction du signal d'onde gravitationnelle de Virgo à l'aide d'un dispositif d'étalonnage utilisant la pression de radiation laser." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY060/document.
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Les ondes gravitationnelles sont des solutions aux équations gourvenant la dynamique de la gravitation prédite en 1918 à partir de la théorie de la Relativité Générale d'Einstein. Elles représentent la propagation d'une oscillation de l'espace-temps induisant d'infimes variations de distance sur leur passage entre des masses libres. Depuis deux décennies, un réseau d'interféromètres de Michelson kilométriques a été développé et mis en opération à travers le monde afin de prouver l'existence des ondes gravitationnelles en détectant leur passage sur Terre. Leur signature est recherchée dans un canal de détection étalonné, obtenu à partir des mesures fournies par le détecteur et reconstruisant le signal absolu d'une onde gravitationnelle le traversant. La vérification de la procédure est nécessaire pour déceler d'éventuelles erreurs systématiques d'étalonnage biaisant l'exploitation du canal par les analyses des données. Depuis plusieurs années, une nouvelle technique d'étalonnage est développée à cette fin dans les différents interféromètres du réseau et repose sur la pression de radiation d'un laser modulé en puissance afin d'induire un déplacement étalonné de l'un de ses miroirs. Le dispositif, appelé étalonneur laser, permet de reproduire le passage d'une onde gravitationnelle connue et d'en vérifier la reconstruction dans le canal de détection. Le travail de cette thèse a concerné la mise en \oe uvre de cette technique pour l'interféromètre franco-italien Virgo afin de vérifier la reconstruction de son signal d'onde gravitationnelle. Le principe de fonctionnement de l'étalonneur laser installé sur le site est d'abord détaillé et son étalonnage est ensuite décrit avec les campagnes de mesures réalisées. Enfin, les vérifications faites durant les deux périodes de prises de données de Virgo qui se sont déroulées entre 2010 et 2011 seront présentées. Les résultats ont permis de valider la reconstruction du signal d'onde gravitationnelle de Virgo et ses incertitudes confirmant leur impact négligeable sur l'analyse des données<br>Gravitational waves are solutions to equations governing the dynamics of gravitation predicted from Einstein's theory of General Relativity in 1918. Gravitational waves describe ripples of space-time producing weak variations of distance between free masses along their propagation. Over the past two decades, an international array of ground-based, kilometer-scale Michelson interferometers has been developed to detect gravitational waves going through Earth and is now in operation. The gravitational wave signature is sought in a calibrated stream obtained from detector output measurements and giving the absolute signal of a gravitational waves going through it. A check of the procedure is required to avoid potential systematic calibration errors leading to an incorrect data stream and bias in its use by data analysis. Since severals years, a new calibration technique is developed for that purpose for each network's interferometer and uses the radiation pressure of a power-modulated laser to induce calibrated displacements of their mirrors. The associated setup, called Photon Calibrator, allows to mimic a gravitational waves passing the detector in order to verify its reconstruction in the detection channel. The scope of this thesis is the implementation of this technique for the French-Italian interferometer Virgo to check its gravitational wave signal reconstruction procedure. The operating principle of the setup installed is first described and its calibration is then detailed with measurement campaigns performed. Finally verifications performed for the two Virgo Science runs performed between 2010 and 2011 are presented. The conclusion of this study allowed to the validate the Virgo gravitational wave signal reconstruction with its uncertainties and has confirmed their negligeable impact on data analysis
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Deichmöller, Jacqueline [Verfasser], Martina [Gutachter] Havenith, and Christian [Gutachter] Herrmann. "Micro-spectroscopy : magnetic resonance force microscopy based approach for the detection of light excitable triplet electron spins and vibrational spectroscopy in medical plasma science / Jacqueline Deichmöller ; Gutachter: Martina Havenith, Christian Herrmann ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2021. http://d-nb.info/1230631437/34.
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Coutee, Adam S. "Virtual Assembly and Disassembly Analysis: An Exploration into Virtual Object Interactions and Haptic Feedback." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05272004-174324/unrestricted/coutee%5adam%5s%5200407%5phd.pdf.
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Thesis (Ph. D.)--School of Mechanical Engineering, Georgia Institute of Technology, 2005. Directed by Bert Bras.<br>Bras, Bert, Committee Chair ; Baker, Nelson, Committee Member ; Griffin, Paul, Committee Member ; Paredis, Chris, Committee Member ; Rosen, David, Committee Member. Vita. Includes bibliographical references.
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Draper, Stephen R. ""EOD, Up!" how explosive ordnance disposal forces can best support special operations forces." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FDraper.pdf.
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Williams, Shara Carol. "Patterning nanocrystals using DNA." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/825530-PLgXcs/native/.
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Thesis (Ph.D.); Submitted to the University of California at Berkeley, Berkeley, CA (US); 1 Sep 2003.<br>Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--55024" Williams, Shara Carol. National Institutes of Health (US) 09/01/2003. Report is also available in paper and microfiche from NTIS.
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Bueno, Carolina de Castro. "Desenvolvimento de um nanobiossensor para o monitoramento da qualidade ambiental no setor agrícola." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/1172.
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Previous issue date: 2013-02-26<br>Financiadora de Estudos e Projetos<br>The elaboration of highly-sensitive and selective functional nanobiosensors has significant applications for purposes of resilience and conservation of natural resources, to contribute on projects aimed to pointing out degraded and contaminated areas (soil and water), as well as being a quality indicator. In the present work, a nanobiosensor has been developed based on the biomimicry of the action mechanism of the herbicides in plants coupled with the Atomic Force Microscopy (AFM) tools. To sense the herbicide molecule at very low concentrations, the technique of the sensor construction was based on chemical functionalization of the surfaces of the AFM probes and substrate in order to prioritize covalent bonds and to improve the molecules flexibility, as well as to achieve reproducibility and accurate results. The architecture and molecular design of the nanobiosensor were based on the molecular spatial arrangement, binding efficiency and localization, host-guest specificity, and its binding energies which were analyzed by Molecular Docking and Molecular Dynamics Simulation. The results were based on the adhesion force (carried out by force curves data) between the AFM probe functionalized with ACCase enzyme and the substrate functionalized with herbicides. The results indicate that the specific target molecule of agrochemical was efficient, when compared with others nonspecific agrochemicals. The difference between the values of specific recognition (diclofop) and nonspecific (imazaquin, metsulfuron and glyphosate) is, on average, 90%. This evidence validates the selectivity and specificity of the nanobiosensor. This work presents the first evidence of nanolevel detection of diclofop by AFM probes sensors.<br>A elaboração de nanobiossensores altamente sensíveis e com seletividade funcional tem aplicações importantes para fins de resiliência e conservação dos recursos naturais que podem contribuir em projetos que visam a apontar áreas degradadas e contaminadas (solo e água), além de ser um indicador de qualidade. No presente trabalho, um nanobiossensor foi desenvolvido com base na biomimética do mecanismo de ação dos herbicidas nas plantas, juntamente com as ferramentas de Microscopia de Força Atômica (AFM). Para detectar a molécula do herbicida diclofop, a técnica da construção do biossensor se baseou na funcionalização química das superfícies de cantilevers de AFM e do substrato, onde a molécula alvo foi fixada. Através da funcionalização química dos cantilevers e substratos priorizam-se as ligações químicas, aumentando a especificidade do nanossensor. O design e arquitetura molecular do nanobiossensor foram baseados no arranjo molecular espacial, na eficiência e localização da ligação, na especificidade de interações enzima-substrato e suas energias de ligação, as quais foram analisadas por Docking Molecular e Dinâmica Molecular. Os resultados foram baseados na força de adesão (obtidos através de curvas de força) entre a ponta do AFM funcionalizada com a molécula sensora (enzima ACCase) e do substrato funcionalizado com herbicidas. Os resultados indicam que a molécula alvo do agroquímico que inibiu especificamente essa enzima foi eficiente, quando comparado com outros herbicidas não inibidores. A diferença entre os valores de reconhecimento específico (diclofop) e não específico (imazaquin, metsulfuron e glifosato) foi, em média, 90%. Esta evidência comprova a seletividade e especificidade do nanobiossensor. Este trabalho apresenta a primeira evidência da detecção ao nível molecular do diclofop por sensores de ponta de AFM.