Dissertations / Theses on the topic 'Gamma bond'
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Kojukhov, Artyom. "Assessment of disulfide bond formation during co-translational folding of synonymous codon variants of recombinant gamma-B crystallin." Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu152571031230488.
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McLeod, Jane. "Analysis of Gamma-Secretase and Amyloid Precursor Protein in Bone." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485129.
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y-secretase IS an intramembrane protease responsible for the cleavage of numerous molecules which regulate osteoblast activity, such as Notch and EphrinB2. Cleavage of its substrates results in release of a fragment into the extracellular space, and a Cterminal peptide into the cytoplasm. Amyloid precursor protein (APP) is also processed by y-secretase, though its role in bone is unknown. Amyloia-p (AP) peptides are secreted into the extracellular space as a result ofy-secretase activity on APP, and in the brain can aggregate to form the plaques characteristic of -Alzheimer's disease (AD). The amyloid intracellular domain (AICD) binds to the nuclear adaptor protein Fe65 in the , . cytoplasm, and translocates to the nucleus to form a transcriptionally active AFT complex with Tip60. In this study the expression, cleavage and potential function of APP were investigated during osteogenesis. Expression of all y-secretase subunits (pS 1, PS2, APH-la, APH-1P, Net, PEN-2) was confirmed throughout osteogenesis and a significant increase in enzyme activity was observed during osteogenic differentiation by use of a specific fluorimetric assay. Characterisation ofAPP in osteoblasts identified expression and processing of a longer isoform of APP in osteoblasts compared to neuronal APP, which contained an additional Kunitz protease inhibitory domain. Application of y-secretase inhibitors confirmed that this enzyme specifically cleaves APP within differentiating mesenchymal stem cells (MSCs). A specific chemiluminescent immunoassay demonstrated secretion of Ap by osteoblasts. MSCs showed a significant increase in adhesion to extracellular matrices containing aged Ap plaques compared to non-aged Ap peptide controls and Ap plaques were localized to the endosteal and periosteal surfaces in sections of adult rat ulna. Expression of the AFT complex components, Fe65 and Tip60, was confirmed throughout in vitro osteogenesis and over-expression of both AICD and Fe65 in C3HlOT~ stromal cells resulted in colocalisation within discrete domains of the nucleus. JlCT analysis (15Jlm resolution) of vertebrae from a 12 month old AD mouse model, Tg2576, which over-expresses a mutant APP resulting in increased y-secretase cleavage, showed' a decrease in bone volume, surface area and thickness compared to wild type controls. These findings indicate that APP may function as a novel regulator of osteoblastic activity, with functions ranging from adhesion to regulation of gene transcription.
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Mossop, J. R. "Coherent gamma-ray scattering and transmission measurements in bone densitometry." Thesis, University of Surrey, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383627.
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Ramsey, Daniel S. "Effects of Gamma Irradiation on the Damage Processes in Human Trabecular Bone." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1279224864.
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Baker, Amelia Rachel Haas. "Environmental PPAR-gamma agonists accelerate aging of bone and impair lymphopoiesis." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12274.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.A growing number of environmental contaminants, including phthalates and organotins, are being recognized for their ability to activate peroxisome proliferator-activated receptor γ (PPARγ) and promote adipogenesis, and have been termed environmental obesogens. Organotins have been pollutants of concern in the marine environment due to use as antifoulants; however, organotin use in wood preservatives, plastics manufacturing, and agricultural pesticides has caused widespread environmental contamination. Tributyltin (TBT) is a highly potent activator of PPARγ, as well as its dimerization partner RXR. Bone marrow (BM) is a multifunctional organ which supports bone homeostasis, lymphopoiesis and whole body energy homeostasis. BM multipotent mesenchymal stromal cells (BM-MSCs) differentiate into adipocytes and osteoblasts, the balance of which constitutes the BM microenvironment. PPARγ sits at the crossroad, promoting adipogenesis and suppressing osteogenesis. Osteoblasts are necessary for optimal lymphopoiesis and adipocytes negatively regulate lymphopoiesis. With age, increased marrow adiposity is associated with concomitant loss of osteoblasts, and reduced cellular and humoral immunity. We tested the hypothesis that TBT skews the BM microenvironment, increasing marrow adiposity and suppressing osteoblast differentiation, ultimately impacting both bone quality and lymphopoiesis, a process resembling premature bone aging. TBT induced adipogenesis in a BM-MSC cell line in a PPARγ-dependent manner and also activated liver X receptor (LXR)-dependent gene transcription. TBT concomitantly induced adipogenesis and suppressed osteogenesis in an ex vivo BM-MSC model and increased marrow adipogenesis and reduced cortical bone in vivo. These changes in differentiation were accompanied by PPARγ upregulation and Runx2 downregulation. Surprisingly, shRNA-mediated knockdown of PPARγ revealed its potential role in early osteogenesis. Experiments in ex vivo cultures also revealed that TBT modifies BM-MSC differentiation distinctly from either a PPARγ or an RXR agonist; a likely mechanism, activation of LXR also was evident in vivo. At environmentally relevant concentrations, TBT directly induced apoptosis in developing B cells in vitro and suppressed developing and peripheral B cells in vivo, likely in part by altering the microenvironment in which they mature. Collectively, these studies contribute to the understanding of how environmental contaminants alter the adipocyte-osteoblast balance, contributing new mechanism-based information on how exogenous exposures affect the interrelationship between lymphopoiesis and the BM microenvironment.
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Morgan, Helen M. "A gamma-ray backscattering technique for in vivo body composition studies." Thesis, University of Bath, 2001. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340992.
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Jawa, Zabah Muhammad. "Optimal utilization of gamma camera time in Tc-99m MDP bone scintigraphy." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1824.
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Thesis (MScMedSc (Medical Imaging and Clinical Oncology. Nuclear Medicine))--University of Stellenbosch, 2007.Introduction: Whole body bone scintigraphy with Tc-99m MDP is able to provide a survey of the entire skeleton. The question arises if it is mandatory to perform a whole body bone scan in all patients, irrespective of the clinical indication. The aim of this study is to determine the implications of performing limited imaging in patients who had whole body bone scan for various clinical patholgy with Tc-99m MDP, in order to determine if limited imaging would be acceptable in selected pathologies. This may enable gamma camera time to be optimally utilized in units with limited facilities. Materials and Methods: Reports of 3015 patients with various clinical pathologies who had whole body bone scans with Tc-99m MDP in our department from January 2002 to December 2004 were retrospectively reviewed. The presence of pathologic radiotracer uptake was analyzed in order to establish the pattern of distribution. Clinically significant skeletal lesions were classified according to the anatomical regions where they were located viz; skull (including the neck), axial skeleton (including the pelvis and shoulders) and limbs. Results: Our results showed that in patients with lung cancer, soft tissue sarcoma, and myeloma, there was an error in more than 25% of patients when limited imaging was performed. In patients with cancer of the breast, prostate, kidney, gastrointestinal system, and reproductive system and lymphoma there is an error in less than 5% of patients when limited imaging is employed. For iv patients with more localized musculoskeletal disorders such as suspected stress fractures, complicated joint prosthesis and avascular necrosis of the femur head, regional imaging of the area of pathology showed a percentage error of less than 6%.
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Ndayizeye, Fernand, and Maxamed Abdiraxman. "Renhetens inverkan på vidhäftningen mellan gammal betong och pågjutning." Thesis, KTH, Byggteknik och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102111.
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Detta examensarbete har genomförts på uppdrag av CBI Betonginstitutet. Handledare till examensarbetet har varit professor Johan Silfwerbrand från CBI och examinator Per Roald från Kungliga Tekniska Högskolan i Haninge. Idag är betong ett byggmaterial som används i stor omfattning tack vare sin beständighet, miljövänlighet och lönsamhet. Betong hittar man i både gamla och nyproducerade konstruktioner. Även med bra egenskaper kan betong vara ofullkomlig när den prepareras på fel sätt. För att underlätta gjutning och arbetbarhet av betong användes förut i många fall mycket vatten och detta resulterade i att beständigheten på betong försämrades. De flesta gamla betongkonstruktionerna är nu i stort behov av renovering. Det synliga beviset kan vara spricknärvaro på ytan och detta kan ha följd att vatten tränger in och orsakar bland annat frost- och saltangrepp samt korrosion i armering. Betong som är skadad eller sliten kan behöva renoveras genom att avverkas delvis eller helt. För att hitta en lämplig avverkningsmetod och reparationsmaterial behöver man först ta reda på skadorna, ställa krav på lagningen, tänka på hur lagningen kommer att utföras och hur upprepningen av skadan ska förebyggas. För att reparera den skadade betongen, avverkas den först och sedan gjuts pågjutningar på den friska och kvarstående delen. Pågjutningar används även i flerskiktsgolv t ex gjuts pågjutningar på prefabricerade bjälklag i olika köpcentrum. Det finns flera typer av bilningsmetoder och de påverkar den kvarstående betongen på olika sätt. De mest använda metoder är vattenbilning och hydraulisk bilning. Vattenbilning är den mest använda inom anläggningssektorn och den effektivaste och lönsammaste metoden. Betongen bilas bort med högtrycksvatten och lämnar en grov och skonsam yta på den friska betongen. Hydraulisk bilning är den äldsta, billigaste och enklaste metoden men nackdelen är att den orsakar mikrosprickor i den friska betongen. Efter betongbilningen måste man se till att man har förutsättningar för en god vidhäftning mellan gammal och pågjuten betong. Vidhäftning är beroende av ett antal faktorer och de fem viktigaste av dem är renhet, mikrosprickfrihet, frånvaro av cementhud, god kompaktering och god härdning. I första delen av examensarbetet testas en provningsmetod som mäter hur ren en motgjutningsyta är. I detta fall används en vit mikrofiberduk som krontrollmätare på renhet. Olika varianter av smuts applicerades på ytan av en betongplatta för att testa mikrofiberdukens uppsugningsförmåga. Mikrofiberduken S-sveptes över den smutsiga betong ytan och redan där sågs det tydligt hur bra mikrofiberduken är på att absorbera smuts. På samma sätt utfördes det på en ren yta och den använda duken förblev vit vilket är ett tydligt bevis på att ytan på betongplatta är helt ren och redo för pågjutning. Examensarbetets andra del tar upp en jämförelse mellan vidhäftningen på en ren pågjuten motgjutningsyta och en oren motgjutningsyta. Vi studerade renhetens inverkan på vidhäftningen mellan gammal och pågjuten betong och som avverkningsmetod användes vattenbilning. För att utföra det, har två betongplattor gjutits och sedan vattenbilats. Den bilade ytan på både plattorna delades i olika delar, där olika varianter av smuts applicerades på halva betongplattan och andra halvan var den rena referensen. Efter detta göts ny, pågjuten betong på båda betongplattorna. Fyra veckor senare togs dragtester för att se om draghållfasthet försämras i över-, underbetong eller i fogen på grund av orenhet jämfört med referensen. Renhet har en stor påverkan på vidhäftningen mellan gammal och ny, pågjuten betong. Draghållfastheten försämras om motgjutningsytan inte är helt ren. Beviset är ett brott i fogen mellan betongskikten, med en väldig liten dragkraft och det syns tydligt att smuts som olja eller träflis precis i fogen när borrcylinder dras ut. För att lösa problemet rekommenderas att använda en vit mirakel duk för att vara säker att motgjutningsytan är helt ren innan pågjutningar gjuts på och detta bevisas med en oförändrad vit färg på duken.This Bachelor’s thesis project has been commissioned by Swedish Cement and Concrete Research Institute. Our supervisor for this thesis project has been Prof. Johan Silfwerbrand and examiner Per Roald from The Royal Institute of Technology in Stockholm. Nowadays, concrete is a building material that is widely used because of its durability, environmental friendliness and profitability. Concrete can be found in both old and new designs produced. Even with good performance concrete can be imperfect when it is prepared incorrectly. To facilitate the handling of concrete plenty of water was often used before and this resulted in concrete deterioration. Many old concrete structures are now in great need of renovation. The visible proof can be the presence of micro cracking on the surface and this may be due to the ingress of water in the concrete and causes including freezing and salt attack and corrosion of the reinforcement. Concrete that is damaged or worn may need to be removed partly or completely. Appropriate removal methods and repair materials are needed, the causes of damage has to be determined, establishing of requirements for repair of concrete, the process of repairing has to be settled and the prevention of the repetition of the damage has to be determined. The damaged concrete has to be removed and be replaced by new overlay concrete. The overlay concrete is used as well in multi-layer floor, for example in various shopping centers overlay concrete is placed on precast slabs. There are several methods of concrete removal and they have different impact on the surface of the remaining concrete. The most widely used methods are the water jet and the hydraulic jetting. Water jet or hydro demolition is the most widely used in civil engineering sector and an efficient and profitable method. The concrete is removed by high pressure water that leaves a rough and gentle surface of the remaining concrete. Hydraulic jetting is the oldest, most common method and easiest concrete removal method. The negative impact of this method is that it causes micro cracks on the remaining concrete. After the concrete has been removed there is a need to ensure that the conditions of getting a good bond between the old concrete and the overlay concrete are there. A good bond is dependent on a number of factors, and five of them are most important: micro cracks absence, the absence of laitance layer, cleanliness, high compaction and good curing. In the first part of the thesis it is tested a test method that measures how clean the surface, there the overlay concrete will be placed, is. In this case, a white microfiber cloth is used as the crown control measure of cleanliness. Different types of dust and contaminations are applied to the surface of a concrete slab to test the cloth’s capacity to absorb the contaminations. The microfiber cloth is swept with S-pattern onto the contaminated concrete surface and already there it was obvious how good microfiber cloth is at absorbing dirt. In the same way this process was performed on a clean surface and the cloth remained white which is a clear proof that the surface of the concrete slab is perfectly clean and ready for casting. The second part of this thesis deals with a comparison between the adhesion to a clean surface and unclean one. We study the effect of cleanliness on the bond between old concrete and a new-cast concrete overlay with water jet as a removal of the old concrete. To perform it, two concrete slabs were cast and then water jetted. The jetted surfaces of both slabs were divided into different zones, in which different varieties of contaminations were applied to half of the concrete slab and the other half remained clean as a reference zone. After this step the overlay concrete was cast on the surface of both concrete slabs. Four weeks later the test of the tensile bond strength was performed to observe where the strength has been poor and where the fracture of the concrete slabs has been, in other words if the fracture will be whether in the new-cast overlay concrete, in the bond zone or in the substrate concrete. Cleanliness has a profound influence on the bond between old and new cast concrete. The tensile strength is poor on the concrete where the surface wasn’t clean enough. The proof is a fracture on the bond between the concrete layers, with less tension force and it is clearly visible dirt such as oil or chips just on the interface when the drilling cylinder is pulled out. To solve this problem it is advised to use a white miracle cloth to be sure that the surface is completely clean before placement of the new-cast concrete.
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Gosset, Laura. "Etude et optimisation des performances de l'instrument MXT, télescope X à micro-canaux, embarqué à bord de la mission spatiale d'astronomie SVOM." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS002/document.
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SVOM est une mission spatiale franco-chinoise qui sera lancée à la fin de l’année 2021. Son objectif est d’étudier les sursauts gamma et autres sources transitoires du ciel X et gamma. Les sursauts gamma sont des explosions cosmiques brèves et très énergétiques permettant leurs détections à des distances extrêmes. Ils apparaissent de manière aléatoire sur tout le ciel et émettent de la radiation dans une large gamme de longueurs d’ondes, allant de l’émission en infrarouge jusqu’aux rayons gamma. SVOM, qui évoluera en orbite basse autour de la Terre, sera composé de quatre instruments, sensibles du domaine visible aux rayons gamma, et sera couplé à des télescopes situés sur Terre qui effectueront des observations complémentaires dans les longueurs d’ondes allant du visible à de l’infrarouge. Le travail que je présente dans cette thèse est basé sur l’étude des performances du télescope MXT, dont l’optique est inspirée du principe de fonctionnement des “yeux des langoustes”. Elle sera mise en place pour la première fois dans le cadre de télescopes X, nécessitant donc de comprendre la réponse de cette optique. MXT est chargé d’observer, la contrepartie qui suit les sursauts gamma, dite émission rémanente, dans la gamme des rayons X entre 0,2 et 10 keV. Il joue un rôle clé dans la localisation précise de ces sources astrophysiques afin de transmettre, en temps réel, leurs positions aux télescopes situés au sol, qui observeront à leur tour, rapidement et précisément, le phénomène. Au cours de mon travail de thèse, j’ai mis en place un simulateur d’observation de MXT qui m’a permis d’estimer et d’étudier les performances attendues de l’instrument au cours de la mission. J’ai également développé des algorithmes de localisation qui seront implémentés à bord du satellite. Ceux-ci m’ont ensuite permis de tester les capacités de localisation de MXT à partir d’une base de données des rémanences de sursauts gamma et de montrer que 50% de ces rémanences seront localisées plus précisément que la minute d’arc. J’ai enfin appliqué une partie de mes modélisations numériques dans le cas de sources d’ondes gravitationnelles afin d’évaluer la détection des contreparties X d’étoiles à neutrons binairesSVOM is a Sino-French space mission to be launched at the end of 2021. Its objective is the study of gamma-ray bursts (GRBs) and other transient high energy sources. These GRBs are very powerful cosmic explosions that can be detected at extreme distances. They appear randomly on all the sky and emit radiation in a wide wavelength range, from the infrared emission to gamma rays. SVOM space mission will shed new light on the physical phenomena associated to GRBs by detecting and observing them in real time over a wide energy range. The satellite, which will be injected on a low Earth orbit, will carry four instruments sensitive from the visible to the gamma-ray domain. Ground based telescopes will complement the space borne ones and will allow for follow-up observations from the visible to the infrared band. The MXT instrument, whose optics are based on the “lobster eyes” principle, will observe GRBs soft X-rays counterparts (afterglows) between 0.2 and 10 keV. This optics will be used for the first time for an X-ray telescope which means to characterize this optics. MXT will play a key role in the localization of these astrophysical sources that will be transmitted, in real time, to ground based instruments allowing for fast and precise observations. During my thesis, I developed an MXT observation simulator in order to predict the performances of the instrument during the mission. I also developed localization algorithms to be implemented on board the SVOM satellite and made use of the state of the art knowledge about X-ray afterglows in order to predict the localization capabilities of MXT. I demonstrated thaht 50% of these afterglows will be localized with a better precision than the arc-minute. I finally applied my simulation tools in the case of gravitational wave sources and, in particular, to assess the capabilities of MXT to observe bright X-ray counterparts of binary neutron star mergers
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Shuster, Mark D. "Physical and Chemical Modifications of Free Radical Scavengers to Reduce their Radioprotective Potentials for Bacterial Agents." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1134418758.
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Dux, Stephanie J. "The Effect of Gamma Radiation Sterilization on Yield Properties and Microscopic Tissue Damage in Dense Cancellous Bone." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1254317910.
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Johnson, Kenneth. "The Role of Gilt in the Cross Presentation of the Melanoma Antigen gp100." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/623465.
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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.In this study we examine the utility of using CD8+ T cell hybridomas to measure the ability of bone marrow dendritic cells (BMDCs) to internalize cancer proteins and display them to cytotoxic T cells, a process termed cross‐presentation. We test the ability of a newly generated T cell hybridoma called BUSA14 to detect cross‐presentation of the melanoma antigen gp100. BUSA14 produces a dose‐dependent response to human and mouse gp100 peptides. However, cross‐presentation of gp100 by BMDCs using SK‐MEL‐28 human melanoma cell lysates or direct MHC class I‐restricted presentation by B16 murine melanoma cells was not detected. Both SKMEL‐28 and B16 cells express gp100 protein by immunoblot, and gp100 as a membrane bound protein may be concentrated by cell fractionation techniques. We validated our crosspresentation assay with another T cell hybridoma B3Z to detect cross‐presentation of the model antigen ovalbumin. Lastly, we determined that although BUSA14 expresses the coreceptor CD8, BUSA14 lacks CD3 expression, which likely impairs the ability of this hybridoma to respond to engagement of the T cell receptor and contributes to the inability to detect presentation of native gp100 protein. To resolve these issues, we plan to use primary gp100‐specific T cells from pmel mice expressing the same T cell receptor as the BUSA14 hybridoma to detect presentation of gp100 protein. Ultimately, we plan to evaluate the requirements for cross‐presentation of gp100, including a role for gamma‐interferon‐inducible lysosomal thiol reductase (GILT), a disulfide bond reducing enzyme.
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Hérodin, Francis. "Contribution a l'etude des effets d'une reaction inflammatoire et d'une irradiation gamma ou neutron-gamma globale chez la souris." Paris 6, 1988. http://www.theses.fr/1988PA066295.
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Un modele de granulome inflammatoire induit chez la souris par injection souscutanee de microbilles de polyacrylamide est utilise pour etudier la physiopathologie de souris soumises, avant ou apres l'induction du processus inflammatoire local, a une exposition globale a des radiations ionisantes. L'effet suppresseur des radiations ionisantes. Une reaction inflammatoire locale induite depuis 24 h s'accompagne d'un effet radioprotecteur important, qui pourrait etre partiellement explique par une stimulation notable de la myelopoiese
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Falletti, Lola. "Étude de la région de la source non-identifiée HESS J1745-303 avec l'instrument LAT à bord du satellite Fermi." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2013. http://tel.archives-ouvertes.fr/tel-00917396.
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Le LAT est l'instrument principal du satellite Fermi et permet d'étudier le ciel en rayons gamma de 20 MeV à plus de 300 GeV. Sa sensibilité accrue a permis l'augmentation du nombre de sources détectées dans le domaine des hautes énergies. Une partie importante de celles-ci n'a pas de contrepartie connue et une étude multi-longueur d'onde est nécessaire afin de comprendre l'origine du signal observé. Dans un premier temps, cette thèse présente l'étude morphologique et spectrale détaillée de la source non-identifiée HESS J1745--303, qui a été découverte dans le domaine gamma par l'expérience H.E.S.S. en 2006 puis analysée spécifiquement dans un article de 2008, à l'aide des données du LAT. Deux sources ponctuelles situées à une localisation proche de HESS J1745--303 sont présentes dans le catalogue à deux ans de données de Fermi (2FGL) mais une analyse dédiée de cette région est néanmoins nécessaire vu sa complexité. Elle est en effet localisée à ~1° du Centre Galactique et à moins de 0.5° du pulsar de la Souris, les deux sources les plus brillantes en gamma dans cette région. Les différents processus d'émission de photons sont présentés dans un second temps. Leurs simulations permettent d'effectuer une étude approfondie de l'origine de l'émission détectée aux hautes et très hautes énergies par le LAT et par H.E.S.S. L'émission de cette source reste en effet encore énigmatique de nos jours et une étude multi-longueur d'onde est effectuée afin de contraindre les modèles d'émission.
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McGurk, Ross James. "Variation of image counts with patient anatomy and development of a Monte Carlo simulation system for whole-body bone scans." Thesis, University of Canterbury. Physics and Astronomy, 2007. http://hdl.handle.net/10092/1586.
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The optimisation of image quality in medical imaging techniques is a significant factor in favourable patient prognoses. The number of counts in a nuclear medicine image is one factor in determining the diagnostic value of the image. The current study aims to determine the variation in counts in whole-body bone scan images with patient height and weight. Three separate studies were undertaken as part of the investigation. First, 65 whole-body bone scans were analysed together with patient height, weight, age and sex. Weight was found to the most important anatomy influence on image counts. However, significant influences from patient sex and age meant that a useful relationship between image counts and patient anatomy based solely on height and weight could not be determined. For the second study, a model of General Electric Millennium MG gamma camera was created and validated within the SIMIND Monte Carlo software. The results indicate that the model is an accurate representation of the gamma camera. Third, the 4D NCAT whole-body patient phantom was modified to represent the average male and female clinical study participants. The phantoms were used in conjunction with the gamma camera model to simulate the whole-body bone scan procedure. The counts in the simulated images were consistent with the average measured counts of the clinical study indicating that it is feasible to use the NCAT phantom for nuclear medicine bone imaging. However, the phantom’s method of activity distribution should be refined to allow a more realistic distribution of activity throughout the skeleton.
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KOSMISKAS, LUIS O. C. "Análise mecânica de réguas ósseas esterilizadas por radiação gama para uso em bancos de tecidos." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11502.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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PAREDES, WILBER E. B. "Avaliação in vitro da composição e microdureza dos tecidos duros da cavidade bucal submetidos à irradiação gama." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27978.
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A radioterapia clínica é de fundamental importância para o tratamento de lesões malignas localizadas na região de cabeça e pescoço, contudo, a exposição à irradiação ionizante, pode levar a complicações sistêmicas ou locais durante e após o tratamento radioterápico. Dentre estas complicações locais imediatas, destaca-se na cavidade oral a xerostomia e a consequente mucosite oral. A respeito das complicações tardias produzidas pela radioterapia, salientam-se a cárie de radiação e a osteorradionecrose, lesões dose dependentes, com alto nível de incidência nas últimas décadas e de difícil manejo, embora estas se apresentem após o término do tratamento e sob influência de fatores locais. A metodologia proposta no presente estudo visa analisar o efeito que exerce a radiação gama após a aplicação da radioterapia, utilizando-se a dose empregada em pacientes acometidos com câncer de cabeça e pescoço. As amostras foram obtidas a partir de esmalte dentário e dentina radicular humanos e osso mandibular suíno, as quais foram previamente polidas, e em seguida analisadas quanto à microdureza de superfície inicial de todos os grupos. Posteriormente, as amostras foram irradiadas sob uma taxa de dose de 4 Gy por dia, completando uma dose total de 72 Gy. Finalmente, as amostras foram submetidas a análise da microdureza de superfície após irradiação, a qual apresentou resultados estatisticamente significantes a partir dos testes de t de student, ANOVA e Tukey com respeito à diferença da média dos valores iniciais e finais de cada grupo de estudo com um valor de p = 0,00 (<0.05). Quanto à análise morfológica na microscopia eletrônica de varredura (MEV), o efeito deletério da irradiação gama manifestou-se na forma de trincas, quebras e fraturas superficiais dos tecidos analisados e à análise bioquímica pela técnica de reflexão total atenuada por meio da espectroscopia no infravermelho por transformada de Fourier (ATR - FTIR), a degradação dos componentes inorgânicos e a desnaturação dos compostos orgânicos foi evidente, pelo qual determinou-se o efeito deletério da irradiação gama sobre os tecidos duros da cavidade bucal com respeito às propriedades mecânicas, composicionais e morfológicas, e da ação contribuinte desta independente dos fatores locais e sistêmicos no paciente irradiado.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Santin, Stéfany Plumeri. "Avaliação morfológica e biomecânica dos efeitos da radiação gama em osso humano liofilizado ou congelado." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-04022014-153012/.
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Diversos pacientes são beneficiados com ossos armazenados em Bancos de Tecidos e utilizados em cirurgias reconstrutivas ortopédicas e em implantodologia como aloenxertos. No entanto, há uma intensa preocupação em garantir segurança na esterilidade do aloenxerto para proporcionar eficácia no transplante. Para minimizar possíveis contaminações utiliza-se a radiação ionizante como forma de esterilização final, desde que esta seja feita de maneira controlada, evitando possíveis modificações na matriz óssea. No presente trabalho, utilizamos as técnicas de colorimetria para avaliar modificações estéticas, Tomografia por Coerência Óptica, Tomografia por Coerência Óptica sensível à polarização, espectroscopia Raman e ensaios mecânicos de compressão para identificar as possíveis alterações na matriz óssea, ocasionadas pela forma de preservação, assim como, pelas diferentes doses de irradiação. Foram obtidas 8 amostras de fíbulas de 4 doadores, fracionadas de maneira a obter 48 amostras liofilizadas e 48 amostras congeladas. As amostras foram irradiadas com as doses de 15, 25 e 50 kGy comparando os resultados com o controle não irradiado. Observamos uma diminuição na intensidade das cores iniciais, mais relacionada com o processamento e preservação das amostras, e para as amostras irradiadas somente foi observado um aumento da coloração amarelada na dose de 50 kGy. A forma de preservação por liofilização ocasionou maiores modificações na estrutura terciária do colágeno dos ossos irradiados nas diferentes doses, principalmente nas doses acima de 25 kGy, porém estas modificações não foram suficientes para alterar a organização das fibras de colágeno. Quanto à resistência mecânica, verificou-se que as amostras liofilizadas foram menos resistentes que as congeladas e nas doses de 15 kGy e 25 kGy em ambas as formas de preservação ocorreu uma tendência a diminuir a resistência mecânica em relação ao controle.Several patients are benefited with bones stored in Tissue Banks and used in orthopedic reconstructive surgery and implantodology as allografts. However, there is a strong concern to ensure safety in sterile allograft transplantation in order to provide efficacy. To minimize a probable contamination, ionizing radiation is used as a form of final sterilization, since the procedure is done in a controlled manner, avoiding possible changes in the bone matrix. In this dissertation, the techniques of colorimetry were used to evaluate aesthetic modifications; Optical Coherence Tomography, Optical Coherence Tomography sensitive to polarization, Raman spectroscopy and mechanical compression was carried out to identify possible changes in the bone matrix, caused by the preservation method, as well as the different irradiation doses. Eight fibulae from four donors were fractionated and from that forty-eight lyophilized samples and forty-eight frozen samples were obtained. The samples were irradiated with doses of 15, 25 and 50 kGy and the results were compared with the non-irradiated control. A decrease in the intensity of the initial colors was noticed and it was more related to the processing and preservation of the samples; for the irradiated samples, only an increase in the yellowness was observed, in the 50 kGy doses. The lyophilization preservation method caused major changes in the tertiary structure of the bone collagen irradiated at different doses, particularly at doses above 25 kGy, but these changes were not enough to change the organization of collagen fibers. Regarding the mechanical strength, were detected that lyophilized samples were less resistant than those which were frozen. With doses of 25 kGy and 15 kGy, in both forms of preservation, the mechanical strength tended to decrease, compared to the control. Therefore, it was observed that the aesthetic and structural changes caused by the different irradiation doses depend on the processing used in the Tissue Banks, besides the preservation method selected.
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VIEIRA, DANIEL P. "Avaliação dos efeitos da inibição de cadeias imflamatórias e da suplementação exógena de CXCL 12 na hematopoiese de modelos experimentais expostos a doses letais ou subletais de radiação gama." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11618.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Kosmiskas, Luis Otavio Carvalho. "Análise mecânica de réguas ósseas esterilizadas por radiação gama para uso em bancos de tecidos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-30032012-111103/.
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Ao se trabalhar com materiais para a área de saúde, uma das principais considerações é evitar possíveis contaminações, dada a natureza da sua aplicação. Dentre os métodos desenvolvidos para esterilização, a radiação ionizante tem sido amplamente empregada por inúmeros setores da área de saúde pela sua eficácia em eliminar contaminantes biológicos de diversas origens. A problemática da utilização da radiação ionizante em materiais de origem humana, contudo, vai além da questão de sua eficácia como esterilizante, incluindo as possíveis alterações na estrutura do material de escolha. Desta forma, no presente trabalho, buscou-se avaliar qual a extensão das alterações biomecânicas causadas pela radiação em tecidos ósseos. Mais especificamente avaliamos as alterações no módulo de elasticidade, tensão de ruptura e porcentagem de deformação que decorrem do processo de irradiação. Como modelo de eleição foram escolhidas réguas ósseas retiradas da diáfase de fêmures bovinos, simulando as condições de ossos humanos armazenados em Bancos de Tecidos Biológicos. Estas foram congeladas a -70ºC e expostas a doses crescentes de radiação gama (0, 12.5, 25 e 50 kGy). Durante o trabalho foi desenvolvido um sistema de cortes para obtenção de amostras precisas e homogêneas. Os resultados demonstram que há uma diferença significativa entre as características observadas com o aumento da dose de radiação.In the production process of health care products, contamination must be considered as one of the principal hazards to be avoided. Among the developed methods for sterilization, ionizing radiation has largely been used by many sectors in health care area as it is efficient in eliminating biological contaminants of several origins. The difficulty of deploying ionizing radiation in materials of human origin, though, includes which possible alterations it might cause in human tissue. In the present work, the extension of the biomechanical alteration generated by radiation in bone tissue was evaluated by biomechanical methods. More specifically, we evaluated alterations to the elastic modulus, rupture tension and percentage of deformation that are thought to be a consequence of the sterilization process. As a research model, bovine femur struts obtained from the diaphysis were used. The struts were frozen in a temperature of -70 ºC and irradiated with crescent doses of gamma radiation (0, 12.5, 25 e 50 kGy). During this work, a cutting system to obtain precision samples to use in such essays was developed. As results show that there is a significant different between the analyzed characteristics in the different doses of radiation.
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Sherman, Shermel B. "Tibia Morphology & Bone Marrow Adipose Tissue Phenotype is Controlled by Sex Steroids in C57BL/6 Mice." University of Toledo Health Science Campus / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=mco1461972446.
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Veloso, Marcelo Noronha. "Avaliação in vitro dos efeitos da radiação ionizante em tecido ósseo bovino por espectroscopia ATR-FTIR e análise dinâmico-mecânica." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-10012014-111938/.
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A radiação ionizante de fontes de radiação gama ou geradores de raios-x é frequentemente utilizada na ciência médica, como em exames de radiodiagnóstico, radioterapia e esterilização de aloenxertos. A radiação ionizante é capaz de quebrar cadeias polipeptidicas e provocar a libertação de radicais livres, pela radiólise de moléculas de água. A radiação ionizante interage também com o material orgânico a nível molecular, podendo alterar as suas propriedades mecânicas. No caso específico do tecido ósseo, estudos reportam que a radiação ionizante induz alterações nas moléculas de colágeno e reduzem a densidade de ligações cruzadas intermoleculares. O objetivo deste estudo foi verificar as alterações promovidas por diferentes doses de radiação ionizante no tecido ósseo utilizando a técnica de Espectroscopia Transformada de Fourier com Reflexão Total Atenuada (ATR-FTIR), e também a análise dinâmico-mecânica. Amostras de osso bovino foram irradiadas usando irradiador de Cobalto-60, com cinco doses diferentes: 0,01 kGy, 0,1 kGy, 1 kGy, 15 kGy e 75 kGy. Para estudar os efeitos da radiação ionizante sobre a estrutura química do osso foram avaliadas a relação material orgânico por material inorgânico, a relação de sub-bandas de amida I e o índice de cristalinidade. As alterações mecânicas foram determinadas por meio do módulo de elasticidade e do valor do amortecimento. Para verificar se as mudanças químicas e as características mecânicas de osso possuem alguma relação, realizou-se um estudo sobre a correlação entre as análises feitas com os dados espectroscópicos e as análises mecânicas. Foi possível avaliar os efeitos de diferentes doses de radiação ionizante no tecido ósseo. Com a análise por espectroscopia ATR-FTIR, foi possível observar as modificações dos componentes orgânicos e na organização cristais de hidroxiapatita. Também foram observadas alterações no módulo elástico e na tangente de delta (dissipação de energia mecânica). Foram encontradas altas correlações com significância estatística entre a relação das bandas (amida III + colágeno)/v1,v3, PO43- com a tangente de delta, e entre a relação 1/FHMW e o módulo elástico.Ionizing radiation from gamma radiation sources or X-ray generators is frequently used in Medical Science, such as radiodiagnostic exams, radiotherapy, and sterilization of haloenxerts. Ionizing radiation is capable of breaking polypeptidic chains and causing the release of free radicals by radiolisys.of water. It interacts also with organic material at the molecular level, and it may change its mechanical properties. In the specific case of bone tissue, studies report that ionizing radiation induces changes in collagen molecules and reduces the density of intermolecular crosslinks. The aim of this study was to verify the changes promoted by different doses of ionizing radiation in bone tissue using Fourier Transform Infrared Spectroscopy (FTIR) and dynamic mechanical analysis (DMA). Samples of bovine bone were irradiated using Cobalt-60 with five different doses: 0.01 kGy, 0.1 kGy, 1 kGy, 15 kGy and 75 kGy. To study the effects of ionizing irradiation on the chemical structure of the bone, the sub-bands of amide I, the crystallinity index and relation of organic and inorganic materials, were studied. The mechanical changes were evaluated using the elastic modulus and the damping value. To verify whether the chemical changes and the mechanical characteristics of the bone were correlated, the relation between the analysis made with spectroscopic data and the mechanical analysis data was studied. It was possible to evaluate the effects of different doses of ionizing radiation in bone tissue. With ATR-FTIR spectroscopy, it was possible to observe changes in the organic components and in the hidroxyapatite crystals organization. Changes were also observed in the elastic modulus and in the damping value. High correlation with statistical significance was observed among (amide III + collagen)/v1,v3, PO43- and the delta tangent, and among 1/FHWM and the elastic modulus.
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Gutierrez, Sébastien. "Mesures par spectrométrie gamma de l'abondance des radioéléments naturels et artificiels en surface et dans les sols par moyens mobiles (détecteurs au germanium embarqués à bord d'un hélicoptère ou d'un véhicule)." Paris 11, 2002. http://www.theses.fr/2002PA112097.
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Jusqu'au début des années 1980, la spectrométrie gamma aéroportée a été avant tout utilisée pour des applications géophysiques et ne concernait que la mesure des concentrations dans les sols des trois radionucléides naturels (40K, 238U et 232Th). Durant les quinze dernières années, un grand nombre de dispositifs de mesures a été développé, la plupart après l'accident de Tchernobyl, pour intervenir en cas d'incidents nucléaires ou de surveillance de l'environnement. Dans le cadre de l'amélioration des performances des moyens de mesure radiologique mobiles Hélinuc et Autonuc, le laboratoire MSA (Mesures Sol et Aéroportées) s'est doté d'un dispositif de mesure gamma constitué d'une diode Germanium Haute Pureté (Ge) durcie aux vibrations caractéristiques d'un hélicoptère ainsi que d'un spectromètre numérique (DSPec, Ortec) en complément des détecteurs d'iodure de sodium (NaI) utilisés de façon courante. Bien que la sensibilité du détecteur semi-conducteur Germanium soit 30 fois plus faible que celle des détecteurs NaI, sa résolution en énergie 20 fois meilleure permet une identification plus sûre des radionucléides à partir de spectres complexes. Cette thèse a consisté à concevoir un dispositif expérimental, à l'intégrer au dispositif nominal de mesure mobile, ainsi qu'à développer des logiciels adaptés à l'acquisition et au traitement de données. L'ensemble de ce travail a abouti à un dispositif expérimental et à des méthodologies de traitement validées. Enfin, une réflexion a été menée sur la stratégie d'utilisation des détecteurs Ge en fonction de l'environnement radiologique. A la suite de ces travaux, la possibilité de combiner à l'avenir plusieurs détecteurs Ge, soit conjointement, soit en remplacement des détecteurs NaI est envisagéeUntil the beginning of the 1980's, airborne gamma-ray spectrometry was used above all for geophysical applications and only concerned the measurement of ground concentrations of the three natural radionuclides (40K, 238U, and 232Th). Over the last fifteen years, many measuring systems have been developed for use in the event of a nuclear accident or for environmental monitoring. As part of its programme to improve the performance of its mobile radiological measurement resources, (Hélinuc and Autonuc), the MSA laboratory (Mesures Sol et Aéroportées) has acquired a germanium gamma-ray measurement system, consisting of a High Purity germanium diode of 70% efficiency (ORTEC, Ref. GMX-70- 230-P. S. ), specially designed for airborne use from a helicopter and a digital spectrometer (Numerical Analyser DSPec, ORTEC). Although the sensitivity of the germanium semi-conductor detector is 30 times lower than that of the sodium iodide (NaI) detectors frequently used in airborne spectrometer, its energy resolution is 20 times better, giving more accurate identification of radionuclides, especially when complex spectra are involved. This thesis bas consisted in the conception of an experimental device, in its integration to the nominal mobile measurement device, and in the development of adapted acquisition and treatment software. This work bas came to lead to a validated device and treatment methodologies. Finally, a reflection bas been led on the Ge detectors strategy of use in a accordance with the radiological environment. The possibility to combine several Ge detectors in future, either conjointly or in place of NaI detectors is envisaged with reference to this work
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Aronsson, Henrik. "Local Delivery of Bisphosphonates from FibMat Matrix." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11053.
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Improving the functionality and reducing revision rates are important driving forces in the development of orthopaedic implants. FibMat is a fibrinogen based matrix developed towards commercialisation by the company Optovent AB. This matrix can be coated on implants and act as a local drug delivery system for bisphosphonates (BPs). BPs are drugs inhibiting bone resorption, and applied with FibMat to improve stability of implants in bone, e.g. when fixing bone fractures. In this thesis, FibMat loaded with BP (FibMat/BP) was coated on stainless-steel screws and titanium screws in order to investigate some technology properties relevant to its clinical applicability. Bone-mimicking materials were used to study scrape-off effect upon insertion. The coagulation properties of fibrinogen as well as the structural properties of BPs were studied after exposure to gamma radiation.
The screws were coated with FibMat and BP (alendronate and 14C-alendronate) using standard coupling techniques. The total amount and distribution of BP after insertion was measured by liquid scintillation and autoradiography. Coagulation assays were performed in order to determine the coagulation properties of fibrinogen, exposed to doses up to 35 kGy, mixed with thrombin. The structural properties of four different BPs (alendronate, pamidronate, zoledronate and ibandronate), exposed to doses up to 35 kGy were analysed by transmission infrared spectroscopy.
The results show that FibMat/BP coating on porous stainless-steel screws is virtually unaffected by insertion into bone materials. The anodised, planar titanium screws are more affected by the insertion process, but an even BP distribution in the cancellous material is indicated. The coagulation assays show that gamma-irradiated fibrinogen has a slower coagulation process compared to non-irradiated fibrinogen and form interrupted network unable to clot. The chemical structures of the BPs seem unaffected by exposure to gamma irradiation. In conclusion, the FibMat/BP is a promising technology for local distribution of BP in conjunction with bone implants.
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COSTA, ZELIA M. da. "Desenvolvimento de um sistema dosimetrico para situacoes de emergencia envolvendo pessoas do publico em geral." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11136.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Vieira, Daniel Perez. "Avaliação dos efeitos da inibição de cadeias inflamatórias e da suplementação exógena de CXCL12 na hematopoiese de modelos experimentais expostos a doses letais ou subletais de radiação gama." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-30032012-095720/.
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O presente estudo teve como objetivo avaliar o efeito da inibição das cadeias inflamatórias reguladas pela ação do interferon-gama (IFN-γ) e da enzima óxido nítrico sintase indutível (iNOS) no dano radioinduzido após exposição a dose letal (8 Gy) ou moderada a severa (4 Gy) nos tecidos hematopoiéticos (baço e medula) de modelos experimentais irradiados nestas doses. Grupos de camundongos isogênicos C57Bl/6j foram expostos à radiação correspondente a 4 ou 8 Gy em exposições de corpo inteiro em fonte panorâmica de 60Co. Da mesma forma, foram irradiados camundongos cuja expressão de IFN-γ ou iNOS é ausente ou indetectável. Outros grupos receberam via oral por toda a duração do experimento um inibidor atividade de iNOS, aminoguanidina, ou via intraperitoneal uma quimiocina primordial promotora da hematopoiese, CXCL12, até o quarto dia após a exposição. Outra divisão experimental recebeu os dois agentes concomitantemente. Os animais foram sacrificados nos dias 2º, 4º e 8º após a irradiação, e fragmentos dos baços e fêmures foram preservados para histologia. Os esplenócitos e células não aderentes da medula óssea femoral foram removidos e divididos, fornecendo alíquotas para posterior RT-PCR e suspensões celulares apropriadas para ensaios de citometria de fluxo específicos para a detecção da freqüência de populações CD34+. Nestes mesmos dias de experimento, alíquotas de sangue caudal foram coletadas para contagem de hemácias e plaquetas periféricas. Os resultados mostraram que a ausência da produção de interferon-gama no local irradiado aumenta a sobrevivência e a quantidade de células progenitoras hematopoiéticas e que a ausência de iNOS ou seu bloqueio funcional diminuem a extensão do dano radioinduzido nos tecidos hematopoiéticos. Além disso, foi possível observar que a suplementação com CXCL12 sintética aumenta a freqüência do fenótipo CD34+ P.chave: radiação ionizante; medula óssea; óxido nítrico; aminoguanidina nos baços dos modelos testados, e que seu efeito parece antagonizar com a inibição da produção de NO pela aminoguanidina.This study aimed to evaluate the effect of inhibition of the inflammatory chains governed by the action of interferon-gamma (IFN-γ) and the enzyme inducible nitric oxide synthase (iNOS) in damage after radiation exposure to lethal dose (8 Gy) or moderate /severe dose (4 Gy) in hematopoietic tissues (spleen and bone marrow) of experimental models irradiated at these doses. Groups of isogenic C57Bl/6j mice were exposed to radiation (4 or 8 Gy) in whole-body exposures in a 60Co panoramic source. Similarly, were irradiated mice whose iNOS or IFN-γ expression was absent or undetectable. Other groups received orally in all days of experiments an inhibitor of iNOS activity, aminoguanidine, or CXCL12, a primordial chemokine known as an hematopoeisis promoter intraperitonially by days 0 to 4th after radiation events Another groups received the two agents concomitantly. The animals were sacrificed on days 2nd, 4th and 8th after irradiation, and fragments of the spleens and femurs were preserved for histology. Splenocytes and non-adherent cells from femoral bone marrow were removed and divided, providing aliquots for subsequent RT-PCR and cell suspensions suitable for flow cytometry experiments specific to the detection of the frequency of CD34+ cell populations. In same days of experiment, tail blood samples were collected for counting of peripheral red blood cells and platelets. The results showed that the absence of the production of interferon-gamma at the irradiated sites increases the survival and the amount of hematopoietic progenitor cells and that the absence of iNOS or its functional blockade reduces the extent of radioinduced damage in tested hematopoietic tissues. Furthermore, it was possible to observe that supplementing with synthetic CXCL12 increases the frequency of CD34+ Keywords: ionizing radiation, bone marrow, nitric oxide, aminoguanidine phenotype in the spleens of tested models, and that its effect seems to antagonize the inhibition of the production of NO by aminoguanidine.
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de, Groot Jens Christian [Verfasser], and Dirk W. [Akademischer Betreuer] Heinz. "Structural Basis for Complex Formation between Human IRSp53 and the Translocated Intimin Receptor Tir of Enterohaemorrhagic E. coli & Structural Characterisation of Amorfrutins Bound to PPAR gamma / Jens Christian de Groot ; Betreuer: Dirk W. Heinz." Braunschweig : Technische Universität Braunschweig, 2012. http://d-nb.info/1175824364/34.
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Oshima, Toshiyuki [Verfasser], and Rainer [Akademischer Betreuer] Schmelzeisen. "Effect of gamma-aminobutyric acid lactam (GBP-L) in combination with mesenchymal stem cells (MSCs) and bovine bone mineral (BBM)on bone formation and osseointegration of dental Implants in maxillary sinus augmentation = Der Einfluß von Gabapentin-Laktam in Kombination mit mesenchymalen Stammzellen und bovinem Knochenersatzmaterial auf die Knocheneubildung und Osseointegration von Zahnimplantaten bei Sinusbodenaugmentation." Freiburg : Universität, 2013. http://d-nb.info/1123477906/34.
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Souza, Marina de Oliveira e. "Comparação entre a prova tuberculínica e a detecção dos níveis de interferon-gama no diagnóstico da tuberculose latente em receptores de transplante de células-tronco hematopoiéticas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/99/99131/tde-09112017-152205/.
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O principal fator de risco para tuberculose (TB) em receptores de transplante de células-tronco hematopoiéticas (TCTH) é viver em regiões de alta endemicidade da doença, uma vez que a imunossupressão favorece a reativação da tuberculose latente (TBL). O diagnóstico da TBL pela prova tuberculínica (PT) tem limitações nos imunocomprometidos e testes de detecção de interferon gama podem ser vantajosos. Os objetivos do presente estudo foram comparar a PT com o QuantiFERON® TB-Gold In-Tube (QFT-GIT) no diagnóstico da TBL e determinar a incidência de TB em duas coortes de pacientes submetidos ao TCTH. Duas coortes foram analisadas prospectivamente. Coorte1: receptores de TCTH incluídos desde o período pré-transplante. Coorte 2: receptores de TCTH com doença do enxerto contra o hospedeiro (DECH) crônica em atividade. A PT e o QFT-GIT foram realizados imediatamente após a inclusão em ambas as coortes. Pacientes na coorte 1 com diagnóstico de TBL receberam profilaxia com isoniazida (INH) por nove meses. Na coorte 2, os pacientes foram acompanhados clinicamente, sem receber profilaxia. TB ativa foi investigada prospectivamente de acordo com definição de caso e por coletas periódicas de escarro. Entre os candidatos ao TCTH, a prevalência de TBL detectada pela PT foi de 4,7% e de 7,1% pelo QFT-GIT. Entre os receptores com DECH crônica a prevalência de TBL detectada pela PT foi de 5,3% e de 12,5% pelo QFT-GIT. A comparação entre as técnicas revelou boa concordância (kappa=0.60). Não houve casos de TB na coorte 1. A incidência cumulativa de TB na coorte 2 foi de 3%. Em comparação com alguns estudos, nossos resultados apresentaram menor prevalência de TB, com menos resultados indeterminados pelo QFT-GIT e melhor concordância entre ambos os testes. É provável que a introdução de profilaxia com INH seja benéfica também para os pacientes com DECH crônica.The main risk factor for tuberculosis (TB) in hematopoietic stem cell transplant recipients (HSCT) is to live in regions of high endemicity of the disease, since immunosuppression favors the reactivation of latent tuberculosis infection (LTBI). The diagnosis of LTBI by the tuberculin test (TT) has limitations in the immunocompromised hosts and the interferon gamma release assays (IGRAs) may be advantageous. The objectives of the present study were to compare the TT with QuantiFERON® TB-Gold In-Tube (QFT-GIT) in the diagnosis of LTBI and to determine the incidence of TB in two cohorts of patients undergoing HSCT. Two cohorts were analyzed prospectively. Cohort 1: HSCT recipients included since the pre-transplant period. Cohort 2: TCTH recipients with active chronic graft versus host disease (GVHD). TT and QFT-GIT were performed immediately after inclusion in both cohorts. Patients in cohort 1 with diagnosis of LTBI received prophylaxis with isoniazid (INH) for 9 months. In cohort 2, the patients were followed up clinically, without receiving prophylaxis. Active TB was investigated prospectively according to a case definition criteria and periodic sputum sampling. Among the HSCT candidates, the prevalence of LTBI detected by TT was 4.7% and 7.1% by QFT-GIT. Among the recipients with chronic GVHD, the prevalence of LTBI detected by TT was 5.3% and 12.5% by QFT-GIT. The comparison between the techniques showed good agreement (kappa = 0.60). There were no cases of TB in cohort 1. The cumulative incidence of TB in cohort 2 was 3%. Compared with some studies, our results showed a lower prevalence of LTBI, with less indeterminate results by QFT-GIT and better agreement between both tests. It is likely that prophylaxis with INH is also beneficial for patients with chronic GVHD.
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Faroni, Alessandro. "Expression of GABA receptors in stem cell derived Schwann cells and their role in the peripheral nervous system." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/expression-of-gaba-receptors-in-stem-cell-derived-schwann-cells-and-their-role-in-the-peripheral-nervous-system(5ca8d27c-cfdb-4db7-82fc-44575ca41539).html.
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Peripheral nerve injuries occur with high incidence and often result in profound and permanent impact on the life of patients and on healthcare expenditure. Schwann cells (SC) play a promoting role in peripheral nerve regeneration providing physical and neurotrophic support that aids axon re-growth. However, these beneficial properties are not exploitable in nerve tissue engineering due to the difficulties in SC harvesting and expansion in culture. Adult stem cells derived from bone marrow (BM-MSC) and from adipose tissue (ASC) can be differentiated in SC-like cells and be used as SC substitutes in bioengineered nerve conduits for the improvement of peripheral nerve regeneration. Pharmacological intervention approaches for the treatment of nerve injury are still not clinically available. Nevertheless, γ-Aminobutyric acid (GABA) receptors have been recently suggested as a putative target for such purpose. GABA is the main inhibitory neurotransmitter of the adult brain and interacts with two different receptor types. However, both GABA-A and GABA-B receptor types are functionally expressed also in SC, where they are involved in the regulation of SC physiology and in the development of the peripheral nervous system (PNS).The aim of this thesis was to characterise the GABAergic system of BM-MSC and ASC differentiated into a SC-like phenotype and to evaluate changes in the expression levels following differentiation. Moreover, the effect of specific GABA receptor ligands on cell proliferation and neurotrophic potential of differentiated stem cells were assessed. Using reverse transcriptase polymerase chain reaction, western blot analysis and immunohistochemistry we demonstrated that adult stem cells express several subunits of both GABA-A and GABA-B receptor systems such as GABA-B1a, GABA-B1b and GABA-B2, as well as GABA-A α2 and GABA-A β3. Expression levels and cellular localisation were comparable with adult and neonatal SC cultures used as positive controls, and protein expression levels for some of the subunits changed following glial differentiation. Interestingly, stimulation of GABA receptors with specific agonists influenced stem cell proliferation in two opposite ways. Baclofen, a GABA-B receptor agonist decreased proliferation of SC and differentiated ASC (dASC), but not of SC-like BM-MSC (dBM-MSC). By contrast, muscimol, a GABA-A receptor agonist, increased proliferation in SC and in both dASC and dBM-MSC. This suggests that GABAergic signalling could be a potential player in the mechanisms regulating stem cell differentiation and proliferation as reported in SC. Finally, baclofen treatments on SC and dASC modulated the expression levels and the release of the neurotrophins BDNF and NGF, which are key actors in the processes involved with peripheral nerve regeneration. Although further studies will be needed to clarify the role of GABA receptors in the PNS, the presence of functional GABA receptors on SC-like adult stem cells could represent an exploitable pharmacological target to modulate stem cell physiology and improve their neurotrophic potential for peripheral nerve regeneration.
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Pruß, Axel. "Chemische und physikalische Verfahren zur Inaktivierung von pathogenen Mikroorganismen in allogenen Knochentransplantaten." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2004. http://dx.doi.org/10.18452/13951.
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In allogeneic bone transplantation, the transmission of viral and non-viral infectious pathogens is the most severe undesirable concomitant phenomenon. The investigations published were examined regarding the inactivating capacity of inactivation procedures that are presently performed in bone banks (peracetic acid/ethanol, gamma irradiation, moist heat) against clinically relevant pathogens (aiming at a virus titer reduction of at least 4 log10 TCID50/ml or titer reduction of non-viral micro-organisms of at least 5 log10 cfu/ml). In the suspension experiments, treatment with peracetic acid/ethanol (peracetic acid 2%, ethanol 96%, aqua ad iniectabilia 2:1:1, 4 hours, 200 mbar, agitation) achieved a titer reduction of > 4 log10 already after 5 minutes for a number of viruses (PSR, PV, BVDV). HIV-2 was also inactivated within 5 minutes below the level of detection ( 4 log10 TCID50/ml was only reached after 4 hours. The results mentioned could be confirmed in the carrier test (contaminated spongiosa cuboids used as ‘worst case’ scenario). In the suspension experiment as well as in the carrier test, the HAV titer was reduced after 4 hours by only 3.7 log10 and 2.87 log10, respectively. The preceding step of defatting the spongiosa tissue by chloroform/ethanol was validated using cell-associated HAV and showed an HAV titer reduction of 7 log10. In the investigations regarding non-viral pathogens, all test organisms were completely inactivated by more than 5 log 10 steps (cfu/ml). Gamma irradiation was the second procedure examined. D10 values (irradiation dose required to reduce 90% of the pathogen titers by one log10 step) that were determined in inactivation kinetics experiments (irradiation conditions: –30°C, 60Co source) corresponded to data published so far. In order to provide for maximal safety, an irradiation dose of 34 kGy was recommended for allogeneic bone transplants using BPV and a diaphysis model from human femurs. The ‘Marburg bone bank system’ was the third procedure examined (thermal disinfection, guaranteed temperature of at least 82.5°C for a minimum of 15 min) using centrally contaminated human femoral heads. All viruses were completely inactivated and their titer reduced by more than 4 log10 steps. Vegetative bacteria and fungi were also completely inactivated (>= 6 log10 in the supernatant). As expected, spores and spore-forming pathogens were not sufficiently inactivated and not inactivated, respectively (titer reduction of less than 2 log10 cfu/ml). However, the latter group can be disregarded, since femoral heads are procured in the operation room under sterile conditions and the following production process rules out a secondary contamination with spores. It could be shown in the investigations presented that all three procedures examined guarantee an inactivation of the viruses investigated according to the recommendations by the senior federal authorities. The three treatment procedures offer additional biosafety by a comprehensive inactivation of non-viral pathogens.
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Bono, Jason S. "First Time Measurements of Polarization Observables for the Charged Cascade Hyperon in Photoproduction." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1520.
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The parity violating weak decay of hyperons offers a valuable means of measuring their polarization, providing insight into the production of strange quarks and the matter they compose. Jefferson Lab’s CLAS collaboration has utilized this property of hyperons, publishing the most precise polarization measurements for the Λ and Σ in both photoproduction and electroproduction to date. In contrast, cascades, which contain two strange quarks, can only be produced through indirect processes and as a result, exhibit low cross sections thus remaining experimentally elusive.
At present, there are two aspects in cascade physics where progress has been minimal: characterizing their production mechanism, which lacks theoretical and experimental developments, and observation of the numerous excited cascade resonances that are required to exist by flavor SU(3)F symmetry. However, CLAS data were collected in 2008 with a luminosity of 68 pb−1 using a circularly polarized photon beam with energies up to 5.45 GeV, incident on a liquid hydrogen target. This dataset is, at present, the world’s largest for meson photoproduction in its energy range and provides a unique opportunity to study cascade physics with polarization measurements.
The current analysis explores hyperon production through the γp → K+K+Ξ− reaction by providing the first ever determination of spin observables P, Cx and Cz for the cascade. Three of our primary goals are to test the only cascade photoproduction model in existence, examine the underlying processes that give rise to hyperon polarization, and to stimulate future theoretical developments while providing constraints for their parameters. Our research is part of a broader program to understand the production of strange quarks and hadrons with strangeness. The remainder of this document discusses the motivation behind such research, the method of data collection, details of their analysis, and the significance of our results.
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Heieh, Min-Hua, and 謝旻樺. "Pricing Mortality Bond with Transformed Gamma Distribution." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/56794866765864011977.
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碩士國立清華大學
計量財務金融學系
101
Due to the frequent catastrophes all over the world in recent years, it causes the extreme mortality rate and gives the insurance companies and reinsurance companies a pound. In order to transfer the mortality systematic risk to capital markets, the mortality-linked securities were issued. The issuance of Swiss Re mortality bond in the end of 2003 year is an example. In this paper, we assume the mortality rate has a transformed gamma distribution and the security is priced by an equilibrium method in the discrete time economy. Furthermore, the risk neutral valuation relationship (RNVR) is obtained. The price of any life-related security is the sum of expected payoff discounted by risk-free rate. Finally, under the restricted conditions of the investor’s preference, the distribution of the mortality and wealth, we can obtain the closed-form solution of the mortality-linked securities and we take the Swiss Re mortality bond as numerical example.
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Mnisi, Fikile Muriel. "Gamma-irradiation protection of collagenous biomaterial derived from human bone." Thesis, 2012. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000640.
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M. Tech. Biomedical Technology.Aims to determine whether pure type collagen biomaterial gels can be protected from scission damage by the addition of different fractions from ColBio, resulting in successful cross-linking by g-irradiation.
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"The Search of an ideal implant for peritrochanteric fractures: a comparative study of dynamic hip screw and gamma nail." Chinese University of Hong Kong, 1991. http://library.cuhk.edu.hk/record=b5886928.
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by Leung Kwok-sui.Thesis (M.D.)--Chinese University of Hong Kong, 1991.
Bibliography: leaves 112-121.
ACKNOWLEDGEMENTS --- p.iii
ABSTRACT --- p.v
LIST OF FIGURES --- p.xi
LIST OF TABLES --- p.xvii
CHAPTER
Chapter I --- Introduction --- p.1
Chapter II --- The Evolution of the Fixation Devices for Peritrochanteric Fractures --- p.13
Chapter II.1 --- Patho-anatomy and Biomechanics of Peritrochanteric Fractures --- p.14
Chapter II.2 --- A Review of the Implants Available for Peritrochanteric Fractures --- p.19
Chapter III --- Methodology --- p.39
Chapter III.1 --- Biomechanical Analysis of the Gamma Nail and the Dynamic Hip Screw --- p.40
Chapter III. 1.1 --- The Testing Machine and Equipments --- p.40
Chapter III. 1.2 --- The Design of the Testing Jig --- p.41
Chapter III. 1.3 --- The Test of the Sliding Characteristics of the Gamma Lag Screw --- p.43
Chapter III. 1.4 --- The Biomechanical Behaviour of Gamma Nail Fixation and the Dynamic Hip Screw Fixation in Cadaveric Femora --- p.47
Chapter III.2 --- Randomized Prospective Trial of Gamma Nail and Dynamic Hip Screw in the Treatment of Peritrochanteric Fractures Among Geriatric Patients --- p.51
Chapter III.3 --- Anthropometric Study of Chinese Femora with Respect to the Design of the Gamma Nail and the Application of the Anthropometric Data for the Modification of the Gamma Nail --- p.55
Chapter III.4 --- Method of Statistical Analysis --- p.61
Chapter IV --- Results --- p.62
Chapter IV. 1 --- The Biomechanical Analysis of the Gamma Nail and the Dynamic Hip Screws --- p.63
Chapter IV. 1.1 --- The Sliding Characteristics of Gamma Lag Screw --- p.63
Chapter IV. 1.2 --- The Biomechanical Behaviours of Gamma Nail and the Dynamic Hip Screw --- p.65
Chapter IV.2 --- Clinical Studies --- p.70
Chapter IV.2.1 --- Randomised Prospective Trial of Gamma Nail and Dynamic Hip Screw in the Treatment of Peritrochanteric Fractures --- p.70
Chapter IV.2.2 --- Comparisons between the Clinical Use of Standard and Modified Gamma Nails --- p.75
Chapter IV.3 --- The Anthropometric Study of the Proximal Chinese Femora and the Application of Anthropometric Data on the Modification of Gamma Nails --- p.78
Chapter V --- Discussion --- p.85
Chapter VI --- Conclusion --- p.109
REFERENCES --- p.112
APPENDICES --- p.122
Chapter Appendix 1 --- Data Record Sheet of Retrospective Analysis of Geriatric Fractures Treated in the Prince of Wales Hospital --- p.123
Chapter Appendix 2 --- Calibration Curve of the Linear Variable Differential Transformer (LVDT) --- p.125
Chapter Appendix 3 --- Data Record Sheets for the Randomized Prospective Trial of Gamma Nail and Dynamic Hip Screw --- p.126
Chapter Appendix 4 --- Operative Procedure of Dynamic Hip Screw and Gamma Nail - A Summary and Modifications --- p.132
Chapter Appendix 5 --- Methodology for the Measurement of the Sliding of the Lag Screw of Gamma Nail on Serial X-ray Films --- p.138
Chapter Appendix 6 --- Results of X-ray Measurement and Bone Densitometry Measurement of Cadaveric Femora --- p.142
Chapter Appendix 7 --- Extra Data from the Results of the Randomized Prospective Trial of Gamma Nail and Dynamic Hip Screw --- p.144
Chapter Appendix 8 --- Results of Anthropometric Study of 30 Chinese Femora --- p.145
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Yuen, Evelyn P. "Effects of High Dietary Iron and Gamma Radiation on Oxidative Stress and Bone." Thesis, 2013. http://hdl.handle.net/1969.1/149574.
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Astronauts in space flight missions are exposed to increased iron (Fe) stores and galactic cosmic radiation, both of which independently induce oxidative stress. Oxidative stress can result in protein, lipid, and DNA oxidation. Recent evidence has linked oxidative stress to bone loss with aging and estrogen deficiency. Whether the increased iron stores and radiation that astronauts face are exacerbating their extreme bone loss while in space is unclear. We hypothesized that elevated iron levels (induced by feeding a high iron diet) and gamma radiation exposure would independently increase markers of oxidative stress and markers of oxidative damage and result in loss of bone mass, with the combined treatment having additive or synergistic effects.
Male Sprague-Dawley rats (15-weeks old, n=32) were randomized to receive an adequate (45 mg Fe/kg diet) or high (650 mg Fe/kg diet) Fe diet for 4 weeks and either 3 Gy (8 fractions, 0.375 Gy each) of 137Cs radiation (γRAD) or sham exposure every other day over 16 days starting on day 14. Serum Fe and catalase and liver Fe and glutathione peroxidase (GPX) were assessed by standard techniques. Immunostaining for 8-hydroxy-2-deoxyguanosine (8-OHdG, marker of DNA adducts) quantified the number of cells with oxidative damage in cortical bone. Bone histomorphometry assessed bone cell activity and cancellous bone microarchitecture in the metaphyseal region. Ex vivo pQCT quantified volumetric bone mineral density (vBMD); bone mechanical strength was assessed by 3-pt bending at the midshaft tibia and compression of the femoral neck.
High Fe diet increased liver Fe and decreased volume per total volume (BV/TV). γRAD decreased osteoid surface per bone surface (OS/BS) and osteocyte density. The combined treatment increased serum catalase, liver GPX, and serum iron and decreased cancellous vBMD and trabecular number (Tb.N). High Fe diet and γRAD independently increased number of osteocytes stained positive for 8-OHdG, with the combined treatment exhibiting twice as many osteocytes positively stained compared to the control. Higher serum Fe levels were associated with higher oxidative damage (r =0.38) and lower proximal tibial cancellous vBMD (r =–0.38). Higher serum catalase levels were associated with higher oxidative damage (r =0.48), lower BV/TV (r =–0.40) and lower cancellous vBMD (r =–0.39).
High dietary iron and fractionated 137Cs γRAD leads to a moderate elevation in iron stores and results in oxidative damage in bone and are associated with decreased cancellous bone density. Moderate elevations in iron stores are not only found in astronauts, but also naturally occur in healthy human populations. This healthy population with elevated iron stores may also have increased levels of oxidative stress in the body. Elevated levels of oxidative stress not only increase one’s risk for accelerated bone loss, but also the risk of developing other chronic diseases such as insulin resistance, hypertension, dyslipidemia, and metabolic syndrome.
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Ding, Zih-An, and 丁子安. "The Effects of Gamma-ray Radiation Microbial Decontamination on the Properties of Calcium Sulfate Bone Cement." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/42480324974402824768.
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碩士龍華科技大學
化工與材料工程系碩士班
103
Calcium sulfate cement has been used in bone repaired for many years. The bone cement has good biocompatibility, and the pore size can promote vessels and new bone growth after crystallization. In the mixing process, slurry has good mobility when adding some water, and bone cement slurry can be injected into the irregular shape of the affected area, but it absorbs so rapid in human’s body that it must rely on other chemical compound to extend absorption time. This study investigated that whether calcium sulfate pass through γ-ray sterilization will affect its nature or not. We use non-sterilization powder as the control group, and also use different doses of radiation to sterilize. Then analyzing the powder properties and material properties. According to the result of the experiment, after calcium sulfate powder passed through γ-ray sterilization by FTIR, TGA, XRD and pH value, we can determine that the chemical nature had the little effect. But we could find the result in mechanical property, at 20kGy, it has the best compressive strength which can get up to 44.23Mpa, and at 40kGy, it also get up to 41.84Mpa. At 70kGy, it has a more average compressive and flexural strength, which can withstand higher stresses.
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Zysk, Aneta. "Adoptive transfer of ex vivo expanded gamma delta T cells targeting osteolytic cancer in the bone." Thesis, 2017. http://hdl.handle.net/2440/119272.
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Bone metastases occur in more than 75% of patients with advanced breast cancer. Cancer in bone is associated with bone destruction and is responsible for high levels of morbidity and mortality but is notoriously difficult to treat. Bone destruction is also the primary cause of morbidity in patients with primary bone cancer, such as osteosarcoma, with metastatic spread to the lungs correlating with poor survival. Therefore, clearly new therapies are desperately required to target cancers in the bone. This study explored the therapeutic potential of gamma delta (Vγ9Vδ2) T cell based adoptive transfer using animal models of osteolytic breast cancer and osteosarcoma. Cytotoxic Vγ9Vδ2 T cells were expanded ex vivo from peripheral blood using IL-2 and zoledronic acid (ZOL). In vitro, expanded Vγ9Vδ2 T cells were cytotoxic against a panel of breast cancer and osteosarcoma cell lines and pre-treatment with ZOL sensitised all cancer cells to rapid killing by Vγ9Vδ2 T cells. Adoptive transfer of fluorescently labelled ex vivo expanded Vγ9Vδ2 T cells into NOD/SCID mice localised to cancer lesions in bone. Multiple infusions of Vγ9Vδ2 T cells reduced breast cancer growth, but had no effect on osteosarcoma growth in the bone marrow. However, in both cases, ZOL pre-treatment potentiated the anti-cancer efficacy of Vγ9Vδ2 T cells in bone, protected the bone from cancer-induced osteolysis and decreased the incidence of pulmonary metastases. Collectively these studies suggest this treatment regimen to be an effective immunotherapeutic approach for the treatment of primary and metastatic bone cancers.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2017
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Davis, Tara Lynne. "Heterotrimeric G protein beta : gamma bound to a biologically active peptide : structural definition of a preferred protein interaction surface." 2004. http://edissertations.library.swmed.edu/pdf/DavisT050405/DavisTara.pdf.
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Figueiredo, Rosa Mafalda Amorim. "GABA levels relate to BOLD signal in Neurofibromatosis Type 1." Master's thesis, 2019. http://hdl.handle.net/10316/89654.
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Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de MedicinaA neurofibromatose Tipo 1 (NF1) é uma doença autossómica dominante na qual os níveis de ácido gama-aminobutírico (GABA) estão reduzidos em várias regiões cerebrais e cujas manifestações clínicas incluem alterações da motricidade. Este estudo investiga, pela primeira vez, a relação entre os níveis de GABA do córtex motor primário (M1) dominante e a atividade funcional de ambos os M1s e do cerebelo durante uma tarefa motora na NF1. Vinte e um participantes com NF1 e vinte controlos executaram movimentos síncronos e assíncronos com os dedos indicadores a ritmos crescentes (1 Hz, 3 Hz e 5 Hz). Os níveis de GABA foram medidos no M1 dominante por espetroscopia de ressonância magnética (MRS) e a atividade funcional de ambos os M1s e do cerebelo foi avaliada por ressonância magnética funcional (fMRI). Depois, investigámos a existência de uma correlação entre os níveis de GABA e a atividade fMRI em cada grupo. Este estudo mostrou que o sinal dependente do nível de oxigenação sanguínea (BOLD) é significativamente mais elevado no grupo NF1 do que no grupo controlo em ambos os M1s e no cerebelo. No movimento assíncrono, os níveis de GABA correlacionaram-se positivamente com a atividade fMRI em ambos os M1s dos doentes com NF1. Essa relação ocorreu sobretudo nos ritmos de tapping mais elevados e não foi observada no grupo controlo. Para além disso, os níveis BOLD do M1 não-dominante espelharam os do M1 dominante no grupo NF1. Em conclusão, alterações neuroquímicas e/ou funcionais no M1 e no cerebelo poderão ser a causa da diminuição das capacidades motoras observadas na NF1, devendo, por isso, ser objeto de estudos adicionais no futuro.
Neurofibromatosis Type 1 (NF1) is a common autosomal dominant disorder with reduced gamma-aminobutyric acid (GABA) levels in several brain regions and whose clinical manifestations include motor deficits. This study investigates for the first time the relation between GABA levels of the dominant primary motor cortex (M1) and the functional activity of both M1s and the cerebellum during a motor task in NF1. Twenty-one NF1 subjects and twenty controls executed a finger-tapping task with synchronous and asynchronous movements at increasing rhythms (1 Hz, 3 Hz, and 5 Hz). GABA levels were measured in the dominant M1 using magnetic resonance spectroscopy (MRS) and the functional activity of both M1s and cerebellum was evaluated using functional magnetic resonance imaging (fMRI). We then investigated the existence of a correlation between GABA levels and fMRI activity in each group. This study showed blood-oxygen-level-dependent (BOLD) signal to be significantly higher in the NF1 group compared to the control group in both M1s and the cerebellum. At asynchronous tapping, GABA levels of the dominant M1 positively correlated with the fMRI activity in both M1s of NF1 patients. That was mainly verified at the highest rhythms of tapping and it was not observed in the control group. In addition, the non-dominant M1 BOLD levels mirrored the dominant M1 in the NF1 group. In conclusion, neurochemical and activity changes in the M1 and the cerebellum may underlie the motor deficits observed in NF1 patients, which should be further addressed in future studies.
H2020
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Kuo, Feng-Ju, and 郭鳳如. "Biomechanical Investigations of Lag Screws Used in Gama Nails: Considering Lag Screw Breakage, Interface Pull-Out, and Bone Cut-Out." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/gxkz9q.
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碩士國立臺灣科技大學
機械工程系
99
Gamma nails have been used to treat proximal femoral fractures because of the advantages of immediate weight bearing capability, low blood loss, low infection risk, and shorter operating time. However, they still have the clinical complications such as screw breakage, screw cut-out, and screw loose. In order to reduce the failure rate, this research discussed the different designs of the gamma nail. There is no research to discuss the influence of the lag screw designs of gamma nails for the bending strength, the pull-out strength, and the cut-out strength. Thus, the purpose of this research was to find the optimal factors of gamma nails considered the bending strength, the pull-out strength, and the cut-out strength. Based on L25 orthogonal array, 3D models were created by using SolidWorks, then transformed into ANSYS Workbench to simulate the bending strength, the pull-out strength, and the cut-out strength. Analysis of the variance (ANOVA) was used to find the contribution of design factors, and the optimal combination of the lag screw was also obtained. Finally, the artificial neural network (ANN) models of the lag screws were developed to predict the von Mises stress, the reaction force, and the bone fracture separating degree. The optimal design of gamma nail would be obtained by using the genetic algorithm (GA). In the parametric analysis of this research, the thread length of the lag screw was the most important factor in the three types of the failure modes. The optimal design for the thread length of the lag screw in bending and cut-out strength was 10 mm, but in pull-out strength was 30 mm. We found that the optimal design using ANN and GA were 19.03 mm for thread length, 7.94 mm for outer diameter of upper lag screw, 8.06 mm for outer diameter of lower lag screw, 3.39 mm for pitch, 20 degree for proximal half angle, 0.1 mm for proximal root radius, 7 mm for distance of two lag screw. In addition, the optimal design was in the situation for Wc = 0, Wp = 0.5, Wb = 0.5. The findings of this research can help surgeons select suitable implant for their patients and assist engineers developing better implants.
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[Verfasser], Dinh Hoang Danh Khoa. "Proteomic analysis of the response of murine bone marrow derived macrophages to IFN-γ [IFN gamma] stimulation and infection with Staphylococcus aureus / vorgelegt von Dinh Hoang Dang Khoa." 2010. http://d-nb.info/1011700514/34.
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Štěpánová, Kateřina. "Vývoj B buněk u prasat a úloha gama delta T lymfocytů při imunizaci naivního imunitního systému." Doctoral thesis, 2013. http://www.nusl.cz/ntk/nusl-328683.
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Thesis summary The process of B cell lymphogenesis in swine remains uncertain. Some reports indicate that pigs belong to a group of animal that use ileal Peyers's patches (IPP) for the generation of B cells while others point to the possibility that the bone marrow is functional throughout life. The functional subpopulations of B cells in swine are also unknown. Together with other ruminants, and also birds, γδ T cells in swine may account for >70% of all T cells which is in apparent contrast with humans and mice. The purpose of this thesis was to address these discrepancies and unresolved issues. The results disprove the existing paradigm that the IPP is primary lymphoid tissue and that B cells develop in IPP in an antigen-independent manner. On the other hand, it shows that bone marrow is fully capable of B cell lymphogenesis and remains active at least for the same period of time as it had been speculated for the IPP. This thesis also identified functionally different subsets of porcine peripheral B cells, and shows that CD21 molecules can be expressed in differential forms. Finally, this thesis identifies two lineages of γδ T cells that differ in many functional and phenotype features. This finding may explain why γδ T cells constitute of minority of lymphocytes in circulation of humans and mice.
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Buchsteiner, Philipp. "Scanning Tunneling Spectroscopy of Rare Earth Hexaborides." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1533-A.
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Lahaie, Nicolas. "Mécanismes de régulation du trafic et de l’activité du récepteur GABAB." Thèse, 2014. http://hdl.handle.net/1866/10894.
Full textAbstract:
L’acide γ-aminobutyrique (GABA) est le principal neurotransmetteur inhibiteur du système nerveux central et est impliqué dans diverses pathologies incluant l’épilepsie, l’anxiété, la dépression et la dépendance aux drogues. Le GABA agit sur l’activité neuronale par l’activation de deux types de récepteurs; le canal chlorique pentamérique GABAA et l’hétérodimère obligatoire de récepteurs couplés aux protéines G (RCPG) GABAB. Chacun des récepteurs est responsable de phases distinctes de la réponse cellulaire au GABA. Lors d’une stimulation par le GABA, il est essentiel pour la cellule de pouvoir contrôler le niveau d’activité des récepteurs et au besoin, de limiter leur activation par des mécanismes de désensibilisation et de régulation négative. La désensibilisation nécessite le découplage du récepteur de ses effecteurs, ainsi que sa compartimentation hors de la membrane plasmique dans le but de diminuer la réponse cellulaire à l’agoniste. Les mécanismes de contrôle de l’activité de GABAB semblent anormaux pour un RCPG et sont encore mal moléculairement caractérisés. L’objet de cette thèse est d’étudier la régulation du récepteur GABAB et de sa signalisation par la caractérisation de nouvelles protéines d’interactions étant impliquées dans la désensibilisation, l’internalisation et la dégradation du récepteur.
Une première étude nous a permis d’identifier la protéine NSF (N-ethylmaleimide sensitive factor) comme interagissant avec le récepteur hétérodimérique. Nous avons caractérisé le site d’interaction au niveau du domaine coiled-coil de chacune des deux sous-unités de GABAB et constaté la dépendance de cette interaction au statut de l’activité ATPasique de NSF. Nous avons observé que cette interaction pouvait être dissociée par l’activation de GABAB, induisant la phosphorylation du récepteur par la protéine kinase C (PKC) parallèlement à la désensibilisation du récepteur. L’activation de PKC par le récepteur est dépendante de l’interaction NSF-GABAB, ce qui suggère une boucle de rétroaction entre NSF et PKC. Nous proposons donc un modèle où, à l’état basal, le récepteur interagit avec NSF, lui permettant d’activer PKC en réponse à la stimulation par un agoniste, et où cette activation permet à PKC de phosphoryler le récepteur, induisant sa dissociation de NSF et sa désensibilisation.
Nous avons par la suite étudié la dégradation et l’ubiquitination constitutive de GABAB et la régulation de celles-ci par PKC et l’enzyme de déubiquitination USP14 (ubiquitin-specific protease 14). Au niveau basal, le récepteur est ubiquitiné, et présente une internalisation et une dégradation rapide. L’activation de PKC augmente l’ubiquitination à la surface cellulaire et l’internalisation, et accélère la dégradation du récepteur. USP14 est en mesure de déubiquitiner le récepteur suite à l’internalisation, mais accélère aussi la dégradation par un mécanisme indépendant de son activité enzymatique. Nos résultats suggèrent un mécanisme où l’ubiquitination promeut l’internalisation et où USP14 cible le récepteur ubiquitiné vers un processus de dégradation lysosomale.
La troisième étude porte sur la régulation de la densité de récepteurs à la membrane plasmique par la protéine Grb2 (growth factor receptor-bound protein 2). Nous avons déterminé que Grb2 interagit avec GABAB1 au niveau de la séquence PEST (riche en proline, glutamate, sérine et thréonine) du domaine carboxyl-terminal, et que cette interaction module l’expression à la surface du récepteur hétérodimérique en diminuant l’internalisation constitutive par un mécanisme encore inconnu. Cette inhibition de l’internalisation pourrait provenir d’une compétition pour le site de liaison de Grb2 à GABAB1, ce site étant dans une région interagissant avec plusieurs protéines impliquées dans le trafic du récepteur, tels le complexe COPI et la sous-unité γ2S du récepteur GABAA (1, 2).
En proposant de nouveaux mécanismes moléculaires contrôlant l’activité et l’expression à la membrane du récepteur GABAB par les protéines NSF, PKC, USP14 et Grb2, les études présentées dans cette thèse permettent de mieux comprendre les processus d’internalisation et de dégradation, ainsi que du contrôle de l’activité de GABAB par la désensibilisation, ouvrant la porte à une meilleure compréhension de la signalisation GABAergique.γ-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter of the central nervous system and is involved in diverse pathologies such as epilepsy, anxiety, depression and drug addiction. GABAergic modulation of neuronal activity involves two different subsets of receptors: the GABAA receptor chlorine channel and the heterodimer of G protein coupled receptors (GPCR) GABAB. Each of these receptors is responsible for mediating distinct parts of the GABA-induced signaling. Upon stimulation, it is vital for the cell to control the signaling input and prevent overstimulation, using mechanisms such as functional desensitization and down-regulation to achieve this. The processes controlling GABAB receptor activity are atypical for a GPCR and have yet to be fully characterized. The aim of this thesis is to elucidate the mechanisms controlling GABAB activity by discovering novel proteins interactions mediating receptor desensitization, internalization and ubiquitination. In the first study, we identified the N-ethylmaleimide sensitive factor (NSF) as a GABAB interacting protein and characterized its interaction site as the coiled-coil structure on both GABAB sub-units. We also showed that this interaction is sensitive to the ATPase state of NSF and that agonist treatment of GABAB led to dissociation of NSF from the receptor in a protein kinase C (PKC) dependent manner. Interestingly, GABA-induced PKC activation was dependent on the NSF-GABAB interaction, suggesting a feedback mechanism for PKC. Both PKC and NSF were involved in mediating receptor desensitization, suggesting a novel role of NSF in receptor signaling regulation. In the proposed model, NSF interacts with GABAB at the basal state, and upon agonist stimulation, PKC is activated and can phosphorylate the receptor, promoting NSF dissociation and GABAB desensitization. We then studied constitutive GABAB ubiquitination and degradation and its regulation by PKC and the deubiquitinating enzyme USP14 (Ubiquitin-specific protease 14). GABAB shows a high constitutive ubiquitination and internalization level. Activation of PKC promotes both phenomena and accelerates the rate of lysosomal receptor degradation. In contrast, USP14 promotes post-endocytic deubiquitination of the receptor, but also accelerates receptor degradation in a catalytically-independent manner. Our results suggest a mechanism where PKC-induced cell surface ubiquitination promotes GABAB endocytosis and USP14 interaction promotes endosomal sorting toward lysosomal degradation. In the third study, we identified the growth factor receptor-bound protein 2 (Grb2) as a protein interacting with the PEST (proline, glutamate, serine, threonine rich) sequence of GABAB1 through a SH3-domain interaction and forming a ternary complex with the functional GABAB heterodimer. We showed that Grb2 can regulate cell surface density of GABAB by decreasing constitutive endocytosis, suggesting that this interaction can compete for binding of the PEST sequence with proteins such as the GABAA γ2S sub-unit or the COPI complex (1, 2), promoting higher cell surface stability. In proposing novel molecular mechanisms controlling GABAB signaling and cell surface expression through NSF, PKC, USP14 and Grb2, this thesis highlights the complex regulation of GABAB activity by its functional desensitization, ubiquitination, endocytosis and degradation.