5,672 research outputs found
Breast cancer: Monitoring response to neoadjuvant chemotherapy using Tc-99m sestamibi scintimammography
Get PDFBackground: Aim of the study was to assess the value of scintimammography using Tc-99m sestamibi in the evaluation of tumor response to neoadjuvant chemotherapy. Material and Methods: Results were calculated for 9 patients undergoing neoadjuvant chemotherapy. Scintimammography using 740 MBq Tc-99m sestamibi was performed before, during and after chemotherapy, and sestamibi uptake was scored visually and semiquantitatively to evaluate tumor response. Results: In the case of complete response (n = 3) sestamibi uptake decreased 8 days after beginning neoadjuvant chemotherapy and normalized in the following course. Focal uptake decreased more slowly in patients with partial response (n = 3), who showed clear, persisting tracer accumulation after therapy. The patients without response (n = 3) showed a persisting high tumor activity even after chemotherapy was completed. Conclusions: The preliminary data suggest that in contrast to other imaging modalities scintimammography appears to yield early information regarding tumor response to neoadjuvant chemotherapy
TC vs. Carson Newman College
No full textTC vs. Carson Newman Eagles. #14 is Steve King, class of 1978, and #52 is Shane Small
Assessment of myocardial perfusion with single photon emission tomography
No full textKing Khalid University Hospital, Nuclear Medicine Department #46In order to compare Tc-99m-Sestarnibi to TI-201 in the assessment of myocardial perfusion in the presence of coronary artery disease, 100 patients were studied with single photon emission computerized tomography (SPECT). Segmental analysis was carried out on 77 patients who underwent cardiac angiogram. The overall sensitivity and specificity rates in patients with myocardial infarction were respectively 92.5% and 98% for MIBI, 86.6% and 95% for TI; whereas in patients with chest pain, they were respectively 76.7% and 80% for MIBI, 69.8% and 70.5% for Tl. Tc-MIBI correctly detected II lesions that were normal on TI-201, whereas the latter detected one lesion that was missed by Tc-MIBI. Concluding, we have the impression that Tc-MIBI not only correlated well with TI-201 but also showed marginal superiority over TI-201. Thus, Tc-MIBI is a valid alternative to T1 whenever the latter is not available
Mechanisms for accumulation and migration of technetium-99 in saltmarsh sediments
No full textThis thesis describes the development of analytical methods for both the bulk determination of 99Tc, and determination of 99Tc in sequential extracts from sediments. These methods have been used to collect data, which, along with trace and major element data have been used to interpret the mechanisms for 99Tc input, migration and accumulation in saltmarshes. The inventory of 99Tc stored in the Thornflatt Saltmarsh, Esk Estuary has also been determined. The routine determination of 99Tc in bulk samples uses 99mTc as a yield monitor. Samples are ignited stepwise to 550°C and the 99Tc is extracted using 8M nitric acid. Many contaminants are precipitated with Fe(OH)3 and the Tc in the supernant is pre-concentrated and further purified using anion-exchange chromatography. Final separation of Tc from Ru is achieved by extraction of Tc into 5% TnOA in xylene from 2M sulphuric acid. The yield is determined by γ-spectrometric analysis of 99mTc. Determination of 99Tc is made by liquid scintillation counting. Typical recoveries are in the order of 70-95% and the method has a detection limit of 1.7 Bq/kg for a sample size of 10g. Determination of Tc in sequential extracts uses operationally defined procedures to extract: exchangeable Tc, reducible Tc and oxidisable Tc. An initial water wash is used to extract any occluded Tc and a final leach in 8 M nitric acid is used to dissolve any residual Tc. The isolation of 99Tc uses TEVA resin for Extracts 1-4 and the decontamination procedure developed for bulk analysis for Extract 5. 99mTc was used as a yield monitor, and determination of 99Tc is by liquid scintillation counting. Limits of detection were dependent on the amount of 99mTc tracer used but were found to be as low as 2.4 Bq/kg for a sample size of 2g. A study was made of the mechanisms responsible for the accumulation and migration of Tc in estuarine sediments using sediments collected from saltmarshes at Thornflatt, Carlaverock and the Ribble Estuary. 99Tc was present at determinable activities in all the sediment cores taken from these sites. Good correlations between Tc and CaO as well as CO3 concentrations and poor correlation between Tc and radionuclides adsorbed to inorganic detritus infer a direct input of 99Tc to marsh sediments. Determination of 99Tc in biota living on the marsh also showed that this was not a significant pathway for input of Tc to the sediments. Sequential extraction data imply sorption to an organic fraction of the sediment. Stable element and sequential extraction data indicates that Tc is readily oxidised and remobilised before reprecipitation where redox conditions are favourable. Data indicate a reduction potential between those of the MnIV to MnII reaction and the FeIII to FeII reaction is necessary for re-accumulation to occur, as suggested by published thermodynamic data. Data collected from reducing sediments imply that similar mechanisms are responsible for the accumulation of Mn (e.g. reduction by sulphate reducing bacteria) and the accumulation of Tc. The inventory of 99Tc held within the Thornflatt saltmarsh is proportionally less than that of 137Cs or 241Am when compared to discharges from Sellafield. However a higher proportion of 99Tc is transferred from Seliafield and incorporated into saltmarsh sediments than is suggested by previously published standard distribution coefficient data. Saltmarsh sediments are therefore a more important sink of 99Tc than extrapolations made from inventories of other radionuclides would suggest
Service-oriented models for audiovisual content storage
No full textWhat are the important topics to understand if involved with storage services to hold digital audiovisual content? This report takes a look at how content is created and moves into and out of storage; the storage service value networks and architectures found now and expected in the future; what sort of data transfer is expected to and from an audiovisual archive; what transfer protocols to use; and a summary of security and interface issues
T0-Berekening: Status Quo van UNIBEST-TC
No full textDit rapport gaat in op de ontwikkelingen bij het UNIBETS-TC model. Met dit model wordt het cross-shore en longshore sediment transport berekend. Om inzicht te krijgen in de verbeteringen in het model wordt er in dit rapport een T0-berekening (een berekening op tijdstip T=0) gemaakt. Dit maakt het mogelijk de ontwikkelingen te evalueren door het te vergelijken met een dergelijke exercitie op het moment T1. Met de berekening wordt er antwoord gegeven op de vragen of het UNIBEST-TC model één heel jaar de ontwikkeling van het kustprofiel kan doorrekenen en in hoeverre het model de werkelijkheid beschrijft. Geconcludeerd wordt dat het (nieuwe) UNIBEST-TC model het dwarstransport in de goede orde van grootte bepaald, maar dat het model geen rekening houdt met het ontstaan van banken. Verder onderzoek is nodig. Het model houdt verder goed rekening met de interactie tussen langs- en dwarstransport en biedt daarnaast een goede mogelijkheid om het lot van een zandsuppletie te bestuderen
Sensitivity of a distributed temperature-radiation index melt model based on AWS observations and surface energy balance fluxes, Hurd Peninsula glaciers, Livingston Island, Antarctica
Get PDFWe use an automatic weather station and surface mass balance dataset spanning four melt seasons collected on Hurd Peninsula Glaciers, South Shetland Islands, to investigate the point surface energy balance, to determine the absolute and relative contribution of the various energy fluxes acting on the glacier surface and to estimate the sensitivity of melt to ambient temperature changes. Long-wave incoming radiation is the main energy source for melt, while short-wave radiation is the most important flux controlling the variation of both seasonal and daily mean surface energy balance. Short-wave and long-wave radiation fluxes do, in general, balance each other, resulting in a high correspondence between daily mean net radiation flux and available melt energy flux. We calibrate a distributed melt model driven by air temperature and an expression for the incoming short-wave radiation. The model is calibrated with the data from one of the melt seasons and validated with the data of the three remaining seasons. The model results deviate at most 140 mm w.e. from the corresponding observations using the glaciological method. The model is very sensitive to changes in ambient temperature: a 0.5 ◦ C increase results in 56 % higher melt rates
TC Insight
No full textIn dit project is er een product geïmplementeerd voor Priva. Priva is een bedrijf dat gespecialiseerd is in klimaatbeheersing in de tuinbouw en kantoorgebouwen. Priva levert regeltechnische software en hardware waarop verschillende componenten zoals CV-ketels, radiatoren en klimaatplafonds kunnen worden aangesloten. De software van Priva regelt vervolgens dat de componenten in deze zogeheten klimaatbeheersingsinstallaties met elkaar kunnen samenwerken en een bepaald binnenklimaat bewerkstelligen. In grote klimaatbeheersingsinstallaties zijn veel componenten van elkaar afhankelijk. Als er in één component een storing optreedt, dan kan deze storing effect hebben op de werking van andere componenten. Deze componenten kunnen als gevolg daarvan weer afwijkend gedrag gaan vertonen. Een uitdaging die vaak voorkomt is dat er afwijkend gedrag wordt vastgesteld in een component, maar dat de daadwerkelijke oorzaak van een probleem in een ander deel van de installatie ligt. Als de afhankelijkheden tussen verschillende componenten inzichtelijk in kaart zouden kunnen worden gebracht, dan zou het makkelijker worden om te achterhalen waar precies de oorzaak ligt als er afwijkend gedrag wordt geconstateerd. Deze gedachte vormt het uitgangspunt voor onze opdracht. In ons uiteindelijke product is het mogelijk om van een klimaatbeheersingsinstallatie de afhankelijkheden tussen verschillende componenten weer te geven. Deze informatie is zowel in een voor computers makkelijk verwerkbaar formaat alsook visueel exporteerbaar. Omdat deze software meer inzicht geeft in de werking van klimaatbeheersingsinstallaties is deze gedoopt tot TC Insight. Er is in het ontwikkelproces gebruikt gemaakt van Test Driven Development, een methode die goede designkeuzes afdwingt en testbare code oplevert. Verder is de software iteratief ontwikkeld volgens de Scrum ontwikkelmethode. Deze methode gaf de opdrachtgever een goed beeld van de bezigheden van het ontwikkelteam en gaf de mogelijkheid om vroeg in het proces feedback te geven zodat deze snel verwerkt kon worden.Software TechnologyElectrical Engineering, Mathematics and Computer Scienc
Model TC-497 Overland Train MkII
No full textPhotograph of the Model TC-497 Overland Train Mkii, the largest and most powerful of all the "land trains" produced by LeTourneau. The TC-497 was built for the U.S. Army to transport cargo in the Arctic under a wide variety of road conditions, according to author Eric Orlemann. It contained nine cargo trailers, a control car and two trailing power units. The TC-497 weighed 135 tons. Its overall length was about 527 feet
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