1,819 research outputs found

    Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

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    Abstract Background The safety controls in Resonance Magnetic Imaging (MRI) diagnostic site are numerous and complex. Some of these are contained in international directives and regularly conducted by medical physics expert after acceptance tests, consisting of a series of checks, measurements, evaluations called quality controls (QCs) and made to guarantee the image quality of the equipment. In this context, ensuring that the coils are in proper operating conditions is important to prevent and reduce errors in use and to preserve patient safety. Results A study by thermography was conducted to evaluate temperature changes of MRI coils during Quality Control (QC), in order to prevent any problems for the patient due to Radio Frequency waves. This experiment involves use of a thermal camera to detect temperature variations during MRI scans using head and body coils of two different tomography 1.5 T and 3.0 T static magnetic field. Thermal camera was positioned inside the MRI room to acquire images every 15 s for all the scansions duration. The observations have shown a temperature increase only for body coil of 1.5 MRI tomography, whereas no significative temperature variation has occurred for the other coils under observation. This temperature increase was later related to a fault of such coil. Conclusions The authors believe this simple method useful as first approach, during routinely QCs, to verify coils functioning and so to avoid patient hazards and are preparing a methodological study about functioning of the coils with respect to their temperature variation

    Rare earth based nanostructured materials: Synthesis, functionalization, properties and bioimaging and biosensing applications

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    Rare earth based nanostructures constitute a type of functional materials widely used and studied in the recent literature. The purpose of this review is to provide a general and comprehensive overview of the current state of the art, with special focus on the commonly employed synthesis methods and functionalization strategies of rare earth based nanoparticles and on their different bioimaging and biosensing applications. The luminescent (including downconversion, upconversion and permanent luminescence) and magnetic properties of rare earth based nanoparticles, as well as their ability to absorb X-rays, will also be explained and connected with their luminescent, magnetic resonance and X-ray computed tomography bioimaging applications, respectively. This review is not only restricted to nanoparticles, and recent advances reported for in other nanostructures containing rare earths, such as metal organic frameworks and lanthanide complexes conjugated with biological structures, will also be commented on.European Union 267226Ministerio de Economía y Competitividad MAT2014-54852-

    Biomedical applications of aerospace-generated technology Quarterly report, 1 Sep. - 30 Nov. 1968

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    Biomedical applications of aerospace generated technolog

    Developing novel fluorescent probe for peroxynitrite: implication for understanding the roles of peroxynitrite and drug discovery in cerebral ischemia reperfusion injury

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    Session 7 - Oral PresentationsSTUDY GOAL: Peroxynitrite (ONOO‐) is a cytotoxic factor. As its short lifetime, ONOO‐ is hard to be detected in biological systems. This study aims to develop novel probe for detecting ONOO‐ and understand the roles of ONOO‐ in ischemic brains and drug discovery ABSTRACT: MitoPN‐1 was found to be a ONOO‐ specific probe with no toxicity. With MitoPN‐1, we studied the roles of ONOO‐ in hypoxic neuronal cells in vitro and MCAO …postprin

    Design and Analysis of Cloaked Fluorophores for Rapid Detection and Visualization of Cancer Cells Containing NAD(P)H:Quinone Oxidoreductase-1

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    The development of fluorogenic substrates for real-time tumor cell detection has led to a vastly expanding field for personal oncology. Fluorophores have been studied as appendages to larger scaffolds leading to accumulation of these dyes in tumor cells or their surrounding environment, taking advantage of tumor anatomy. A new class of fluorophores has been developed in which the dye is an active participant in the mechanism of cancer cell detection. These dyes have been conjugated such that their fluorescence has been eliminated or altered and will undergo a change to reveal their fluorescent signal upon activation by a mechanism that is unique to tumor cells. The research presented in this dissertation encompasses the design, synthesis, properties, and utilization of latent fluorophores that are specifically activated by an enzyme that is highly upregulated in tumor cells, NAD(P)H:quinone oxidoreductase-1 (NQO1). These dyes utilize the 2-electron reduction of quinones to hydroquinones, which NQO1 specifically catalyzes. A dye’s fluorescence can be quenched by conjugating a quinone directly to the fluorophore, only to have its signal uncloaked after activation by NQO1. The objectives in this research will be achieved by: (1) the characterization of properties (stability in biological environments, quantum yields) of the quinone, dyes, and their conjugated counterparts; (2) determination of kinetic parameters (Michaelis constant (Km), theoretical maximum velocity (Vmax), catalytic constant (kcat), enzyme efficiency (kcat/Km) of the substrates towards NQO1 and the way solvent affects such parameters during assay conditions; and (3) utilization of a latent fluorophore for in vivo NQO1 analysis (widefield imaging, confocal single-/two-photon microscopy, flow cytometry) and determining the fate of the released fluorophore. Integration of these studies led to the development of two different latent fluorophores that are readily activated by NQO1. Of these two fluorogenic cancer sensors, one was found to possess a highly novel quenching mechanism between the quinone and the dye

    PHARMACEUTICAL AND BIOPHARMACEUTICAL ASPECTS OF QUANTUM DOTS-AN OVERVIEW

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    In the twenty-first century, nanotechnology has become cutting-edge technology. It is interdisciplinary and multidisciplinary, covering numerous fields such as medicine, engineering, biology, physics, material sciences, and chemistry. The present work aims to cover the optical properties, method of preparations, surface modifications, bio-conjugation, characterization, stability, and cytotoxicity of quantum dots (QDs). Articles were reviewed in English literature reporting the pharmaceutical and bio-pharmaceutical aspects of QDs which were indexed in Scopus, web of science, google scholar and PubMed without applying the year of publication criterion. One significant value of utilizing nanotechnology is that one can alter and control the properties in a genuinely unsurprising way to address explicit applications' issues. In science and biomedicine, the usage of functional nanomaterials has been broadly investigated and has become one of the quick-moving and stimulating research directions. Different types of nanomaterial (silicon nanowires, QDs, carbon nanotubes, nanoparticles of gold/silver) were extensively utilized for biological purposes. Nanomedicine shows numerous advantages in the natural characteristics of targeted drug delivery and therapeutics. For instance, protection of drugs against degradation, improvement in the drug's stability, prolonged circulation time, deceased side effects, and enhanced distribution in tissues. The present review article deals with the quantum dots, their optical properties, method of preparations, surface modifications, bio-conjugation, characterization, stability, and cytotoxicity of quantum dots. The review also discusses various biomedical applications of QDs. The QDs-based bio-nanotechnology will always be in the growing list of unique applications, with progress being made in specialized nanoparticle development, the detection of elegant conjugation methods, and the discovery of new targeting ligands

    Biointegrated and wirelessly powered implantable brain devices: a review

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    Implantable neural interfacing devices have added significantly to neural engineering by introducing the low-frequency oscillations of small populations of neurons known as local field potential as well as high-frequency action potentials of individual neurons. Regardless of the astounding progression as of late, conventional neural modulating system is still incapable to achieve the desired chronic in vivo implantation. The real constraint emerges from mechanical and physical diffierences between implants and brain tissue that initiates an inflammatory reaction and glial scar formation that reduces the recording and stimulation quality. Furthermore, traditional strategies consisting of rigid and tethered neural devices cause substantial tissue damage and impede the natural behaviour of an animal, thus hindering chronic in vivo measurements. Therefore, enabling fully implantable neural devices, requires biocompatibility, wireless power/data capability, biointegration using thin and flexible electronics, and chronic recording properties. This paper reviews biocompatibility and design approaches for developing biointegrated and wirelessly powered implantable neural devices in animals aimed at long-term neural interfacing and outlines current challenges toward developing the next generation of implantable neural devices

    Review of photoacoustic imaging plus X

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    Photoacoustic imaging (PAI) is a novel modality in biomedical imaging technology that combines the rich optical contrast with the deep penetration of ultrasound. To date, PAI technology has found applications in various biomedical fields. In this review, we present an overview of the emerging research frontiers on PAI plus other advanced technologies, named as PAI plus X, which includes but not limited to PAI plus treatment, PAI plus new circuits design, PAI plus accurate positioning system, PAI plus fast scanning systems, PAI plus novel ultrasound sensors, PAI plus advanced laser sources, PAI plus deep learning, and PAI plus other imaging modalities. We will discuss each technology's current state, technical advantages, and prospects for application, reported mostly in recent three years. Lastly, we discuss and summarize the challenges and potential future work in PAI plus X area

    Functional nanoparticles for magnetic resonance C-Surgery tools

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    Ο κεντρικός σκοπός αυτής της εργασίας είναι να παρέχει μια γενική επισκόπηση όσων αφορά την χρήση και εφαρμογή των λειτουργικών νανοσωματιδίων στην μαγνητική τομογραφία και της εικονικά καθοδηγούμενης χειρουργικής στον τομέα της ιατρικής. Τα νανοσωματιδιακά σκιαγραφικά μέσα προσφέρουν την δυνατότητα άριστης ανάλυσης και υψηλής ευαισθησίας μαγνητικής τομογραφίας μέσα από την ικανότητα τους να συσσωρεύονται στα παθολογικά σημεία καθώς και την ιδιότητα περεταίρω επεξεργασίας τους μέσω διαφόρων τεχνικών. Τα διάφορα είδη σκιαγραφικών ουσιών αναλύονται εκτενέστερα καθώς και οι πρόσφατες εξελίξεις στον συγκεκριμένο τομέα. Αυτή η διπλωματική αναλύει το συνεχώς αυξανόμενο ενδιαφέρον ως προς τα νανοσωματιδιακά ενεργοποιούμενα σκιαγραφικά μέσα τα οποία ενεργοποιούνται έπειτα από συγκεκριμένα ερεθίσματα και προσφέρουν υψηλή ευαισθησία και εξειδίκευση . Οι αρχές της συσσώρευσης των νανοϋλικών στα χειρουργικά σημεία αναλύονται και αποτελούν προοίμιο για τα οφέλη της νανοϊατρικής στην εικονικά καθοδηγούμενη χειρουργική . Ένας ρεαλιστικός τρόπος για να παρέχουμε άρτια διεγχειρητική εικόνα και ικανοποιητική διείσδυση ιστών είναι η πολυτροπική απεικόνιση βασισμένη σε μοριακές απεικονιστικές τεχνολογίες. Επιπροσθέτως τα λειτουργικά νανοσωματιδιακά μπορούν να χρησιμοποιηθούν σε διαφόρου είδους χειρουργικές επεμβάσεις με στόχο την ολοκληρωτική εξαίρεση των παθολογικών εξεργασιών. Επιπλέον, ο σύγχρονος συνδυασμός της διάγνωσης και θεραπείας ταυτόχρονα και σε πρώτο χρόνο μέσω της χρήσης νανοσωματιδίων στον τομέα της χειρουργικής αναλύεται στα πλαίσια αυτής της διπλωματικής. Τελειώνοντας, αυτή η διπλωματική αναφέρει τις δυσκολίες και τις μελλοντικές προοπτικές όσον αφορά την ανάπτυξη , εξέλιξη και κλινική εφαρμογή των λειτουργικών νανοσωματιδίων στην μαγνητική τομογραφία και στην εικονικά καθοδηγούμενη χειρουργική .The central purpose of this thesis is to provide a general overview of functional nanoparticles for MRI and image-guided surgery and their applications in the medical field. Nanoparticle-based contrast agents offer promising new platforms to increase the resolution and sensitivity of MRI by their enhanced accumulation at disease sites and their large surface area for additional modification with targeting ligands etc. The different types of contrast agents were discussed concurrently with any recent developments. This thesis reviews the ever-evolving interest in nanoparticle-based activatable MRI contrast agents responsive to various stimuli which enhances specificity and sensitivity. The principles of nanomaterials to surgical targets are reviewed, unlocking the advantages of nano-technology in image-guided surgery and multimodal image-guided surgery and assisted synergistic therapy. A pragmatic method to achieve intraoperative visualization with deep tissue penetration and high resolution is multimodal-imaging based on molecular imaging technologies. Furthermore, functional nanomaterials synergize different surgical procedures to eliminate residual lesions. Additionally, theragnostic nanomaterials with surgical applications were discussed. Finally, this thesis mentions the challenges and future perspectives to develop and translate functional nanoparticles for MRI and nanomaterials for image-guided surgery into clinical practice

    Emerging technologies for the non-invasive characterization of physical-mechanical properties of tablets

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    The density, porosity, breaking force, viscoelastic properties, and the presence or absence of any structural defects or irregularities are important physical-mechanical quality attributes of popular solid dosage forms like tablets. The irregularities associated with these attributes may influence the drug product functionality. Thus, an accurate and efficient characterization of these properties is critical for successful development and manufacturing of a robust tablets. These properties are mainly analyzed and monitored with traditional pharmacopeial and non-pharmacopeial methods. Such methods are associated with several challenges such as lack of spatial resolution, efficiency, or sample-sparing attributes. Recent advances in technology, design, instrumentation, and software have led to the emergence of newer techniques for non-invasive characterization of physical-mechanical properties of tablets. These techniques include near infrared spectroscopy, Raman spectroscopy, X-ray microtomography, nuclear magnetic resonance (NMR) imaging, terahertz pulsed imaging, laser-induced breakdown spectroscopy, and various acoustic- and thermal-based techniques. Such state-of-the-art techniques are currently applied at various stages of development and manufacturing of tablets at industrial scale. Each technique has specific advantages or challenges with respect to operational efficiency and cost, compared to traditional analytical methods. Currently, most of these techniques are used as secondary analytical tools to support the traditional methods in characterizing or monitoring tablet quality attributes. Therefore, further development in the instrumentation and software, and studies on the applications are necessary for their adoption in routine analysis and monitoring of tablet physical-mechanical properties
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