• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 169
  • 59
  • 11
  • 9
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 477
  • 253
  • 211
  • 175
  • 68
  • 55
  • 52
  • 45
  • 43
  • 41
  • 31
  • 29
  • 25
  • 25
  • 24
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

99mTc-HYNIC-DAPI-DNA-Bindungsnachweis und Nachweis von DNA-Doppelstrangbrüchen durch 99mTc-HYNIC-DAPI mittels Agarose-Gelelektrophorese

Punzet, Robert 01 April 2014 (has links)
Hintergrund: Ein sehr häufig in der nuklearmedizinischen Diagnostik genutztes Radionuklid ist 99mTc. Es emittiert Gammastrahlung mit einer relativ niedrigen Energie (140 keV) und hat eine kurze Halbwertszeit von 6 h. Zusätzlich zur Gammastrahlung entstehen bei jedem Zerfall von 99mTc Auger-Elektronen. Diese niederenergetischen Elektronen, sehr kurzer Reichweite verfügen über einen hohen LET und erzeugen somit eine ausreichende Energiedeposition, um direkte DSB zu erzeugen. Bei Untersuchungen zu Chemotoxizität und Radiotoxizität mit Zellexperimenten gilt es eine Vielzahl an verschiedenen Schutzmechanismen, Reparaturmechanismen und Signalkaskaden in Zellen zu beachten, welche häufig noch nicht vollständig erforscht sind. Um das schädigende Potential von unterschiedlichen Substanzen und Strahlenqualitäten auf die DNA zu untersuchen, wurde ein zellfreies System gewählt. Ziel dieser Arbeit war es, neben den Strahlenqualitäten der Alpha-, Beta, Gamma- und Röntgenstrahlung die Auger-Elektronen des 99mTc auf ihr Potential zur Induktion von DNA-Strangbrüchen zu untersuchen. Hierfür stand die Substanz 99mTc-HYNIC-DAPI zur Verfügung, welche 99mTc an das Plasmid binden und somit in direkte DNA-Nähe bringen kann. Material und Methode: Alle Versuche wurden mit dem Plasmid pUC 19, einem künstlich hergestellten, bakteriellen Plasmid mit 2686 Basenpaaren, welches als nackte DNA ohne Proteine vorliegt, durchgeführt. Der Vergleich zwischen bestrahltem Plasmid in Ab- und Anwesenheit des Radikalfängers DMSO gibt Hinweise darauf, ob Strangbrüche direkt induziert oder nach Radikalbildung indirekt erzeugt werden. Bei radikalvermittelter Wirkung verhindert DMSO DNA-Strangbrüche und die ungeschädigte Supercoiled-Plasmid-Konformation bleibt erhalten. Nach Bestrahlung des Plasmids erfolgte der Nachweis von Strangbrüchen mittels Agarose-Gelelektrophorese. Bekommt ein Plasmid Einzel- oder Doppelstrangbrüche, so verändert sich seine Konformation zu einem ringförmigen/open circle (ESB) oder einem linearen Plasmid (DSB). Durch veränderte Laufeigenschaften im Agarosegel sind die verschiedenen Konformationen voneinander trennbar. Nach Anfärben der DNA mit dem Fluoreszenzfarbstoff Ethidiumbromid konnte das fluoreszierende Plasmid fotografiert und die Intensität der Konformationsbanden quantifiziert werden. Ergebnisse: Zuerst wurde die Reproduzierbarkeit der Methodik überprüft und festgestellt, dass eine Korrelation zwischen Plasmidmasse und Fluoreszenzintensität besteht. Anschließend wurde in Vorversuchen gezeigt, dass die Inkubationstemperaturen, pH-Werte und der Radikalfänger DMSO keinen Einfluss auf die Plasmidintegrität haben. Bei Bestrahlung mit Röntgenstrahlung, dem Beta-Strahler 188Re und dem nicht DNA-gebundenen Gamma-Strahler und Auger-Emitter 99mTc konnte mit steigender Dosis eine Zunahme an ESB festgestellt werden. Vergleichsproben mit DMSO zeigten keinen Anstieg von ESB, was auf eine radikalvermittelte 67 DNA-Schädigung mittels Reaktiver Sauerstoffspezies (ROS) hinweist. Ab einer Energiedosis von ca. 80 Gy konnten nach Bestrahlung mit 188Re und 99mTc zusätzlich zu den ESB auch DSB nachgewiesen werden. DMSO konnte in den Vergleichsproben sowohl die ESB als auch die DSB erfolgreich verhindern. Bei einer sehr hohen Dosis ≥ 600 Gy zeigte DMSO Kapazitätsgrenzen und es konnten nicht mehr alle Strangbrüche verhindert werden. Die Bestrahlung mit dem Alpha-Strahler (hoher LET) 223Ra fügte, im Vergleich zu Strahlung mit niedrigem LET, dem Plasmid überproportional viele DSB zu. Einige dieser DSB konnten nicht durch DMSO verhindert werden, was auf einen direkten DNA-Schaden bzw. eine zu hohe Radikaldichte hinweist. Ein noch stärkerer direkter Effekt konnte beobachtet werden, wenn 99mTc über die Substanz 99mTc-HYNIC-DAPI an DNA gebunden wurde. Dabei konnten schon ab einer Energiedosis von 4 Gy DSB erzeugt werden, welche trotz Radikalfänger nicht verhindert werden konnten. Schlussfolgerung: Dieser bei 99mTc-HYNIC-DAPI beobachtete Effekt wird den Auger-Elektronen zugeschrieben. Aufgrund ihrer kurzen Reichweite und ihres hohen LET sind sie in der Lage direkte DSB zu erzeugen, wenn sie DNA-gebunden sind oder sich in geringem Abstand zur DNA befinden. Die Ergebnisse der Experimente weisen auf ein therapeutisches Potential von 99mTc hin. Weitere Untersuchungen müssen zeigen, ob eine Adressierung von 99mTc an die DNA im Zellkern einer intakten Zelle zu verwirklichen ist und ob DNA-gebundenes 99mTc durch die Energie der Auger-Elektronen den Zelltod herbeiführen kann. Im nächsten Schritt sollte die Erforschung von Trägersubstanzen erfolgen, welche es ermöglichen Auger-Emitter spezifisch an die DNA von Tumorzellen zu koppeln. / Introduction and aim of the study: A radionuclide commonly used in diagnostic nuclear medicine is 99mTc. It emits gamma rays with a relatively low energy (140 keV) and has a short half-time (6h). In addition to gamma rays, 99mTc radiates so called Auger-electrons with low energy, low range and high linear energy transfer. Due to the high-LET Auger-electrons have a sufficient energy deposition to induce direct double-strand breaks to the DNA. In these experiments we used plasmid DNA to evaluate damage induced to biological systems by different chemotoxical substances and radionuclides as well as external radiation. By using plasmids instead of cell cultures we avoid lots of unexplored signal pathways in cells and it is possible to quantify chemotoxical and radiation damage to the DNA. Materials and methods: The double-stranded plasmid pUC 19 with 2686 bp is used in all experiments. It is a synthetically produced bacterial plasmid without any proteins. To distinguish between directly and indirectly (radical induced) induced damage we used the radical scavenger DMSO. Indirectly induced damage via reactive oxygen species (ROS) can be prevented by DMSO. The quantification of supercoiled forms, single strand breaks (SSB) and double strand breaks (DSB) was measured by the method of agarose gel electrophoresis. After the electrophoresis, agarose gels are dyed in ethidium bromide and imaged with a ccd-camera using ultraviolet transillumination. The bands of the different plasmid forms were quantified through the FIJI computer program. Results: First of all a correlation between plasmid mass and fluorescence intensity was shown. In a pretrial no damaging effect to the plasmid from incubation temperature, pH-value and radical scavenger DMSO appeared. Afterwards we examined chemotoxical SnCl2, external x-rays, the alpha emitter 223Ra, the beta emitter 188Re, gamma- and Auger-emitter 99mTc and the DNA-bound 99mTc-HYNIC-DAPI. The radical scavenger DMSO was used to differentiate between indirect (radical induced) and direct DNA-damage. All different radiation qualities showed an increasing DNA-damage with increasing energy dose. For the low-LET radiation qualities like chemotoxical SnCl2, external x-rays, the beta emitter 188Re and not DNA-bound 99mTc, DMSO showed the quality to prevent the damage. After the deposition of an energy dose ≥ 600 Gy DMSO showed a limitation in his scavenger capacity. During radiation with high-LET beams like 223Ra or DNA-bound 99mTc-HYNIC-DAPI DMSO showed less or nearly no ability to prevent DNA-damage. A 4 Gy dose of 99mTc-HYNIC-DAPI was able to induce DSB into the plasmid. These DSB could not be prevented by DMSO. The lower ESB:DSB ratio for high-LET beams also displays that direct damage is more likely to create DSB than indirect damage. Conclusion: In conclusion we can say that DNA-bound 99mTc-HYNIC-DAPI was most appropriate to induce DSB via a direct effect. It was impossible to prevent this damage due to adding the 69 radical scavenger DMSO. We attribute this to low range, low-LET Auger-electrons and suppose that it may be possible to use DNA-bound 99mTc for therapeutic purpose. Further research has to show if 99mTc can be targeted to the DNA of intact cells and if suitable tracers can be found to safely target and kill tumor cells.
332

Nachweis der adaptiven Antwort nach Bestrahlung von Schilddrüsenzellen mit offenen Radionukliden

Wendisch, Maria 18 November 2010 (has links)
Biologische Systeme sind in der Lage sich an eine Niedrig-Dosis-Bestrahlung anzupassen und eine geringere Sensitivität gegenüber einer nachfolgenden Hoch-Dosis-Bestrahlung zu entwickeln. Dieses Phänomen wird als adaptive Antwort bezeichnet und wurde nach der Bestrahlung mit externen Strahlungsquellen wiederholt in vivo und in vitro untersucht. Im Gegensatz dazu gibt es für die Bestrahlung mit offenen Radionukliden keine systematischen und vergleichenden Untersuchungen. Im Mittelpunkt dieser Arbeit standen der Nachweis sowie die Analyse der adaptiven Antwort an PC Cl3-Zellen nach Bestrahlung mit den offenen Radionukliden Re-188 und Tc-99m. Die Zellschädigung wurde mit dem alkalischen Komet-Assay, zur Bestimmung des initialen DNA-Schadens und dem Koloniebildungstest, zur Ermittlung des klonogenen Überlebens, untersucht. Zur Aufklärung von möglichen Regulationsmechanismen der adaptiven Antwort wurde die Induktion und Reparatur von DSB mit dem gamma-H2AX-Immunfluoreszenz-Assay und die intrazelluläre Radionuklidaufnahme betrachtet. In dieser Arbeit erfolgte erstmals eine systematische Untersuchung der adaptiven Antwort nach Bestrahlung mit offenen Radionukliden in vitro. Insgesamt zeigen diese Ergebnisse, dass nach Bestrahlung mit offenen Radionukliden eine adaptive Antwort ausgebildet wird. Diese ist von der Strahlenqualität während Vor- und Folgebestrahlung sowie der Art der DNA-Schädigung und den initiierten Reparaturprozessen abhängig. Weiter Einflussfaktoren sind die Erholungszeit, die Vorbestrahlung (Dosis, Strahlenqualität) und die Art des Schadensnachweises. Neben den bekannten Regulationsmechanismen wurde erstmals die Reduktion der intrazellulären Radionuklidaufnahme als weitere mögliche adaptive Antwort beschrieben.
333

Precipitation behavior of the super austenitic stainless steel SANICRO® 35 and the effect on impact toughness and pitting corrosion resistance

Li, Shunyi January 2022 (has links)
This research extended the knowledge of the solid phase transformation and the resulting influence on impact toughness and pitting corrosion resistance in super austenitic stainless steel (SASS) SANICRO® 35. A time-temperature-transformation diagram (TTT diagram) was assembled by performing isothermal heat treatments in the temperature range of 650-1050 °C for different periods of time, ranging from 5 min to 500 min. Microstructural analysis via LOM-DIC, SEM-EDS shows that the nose temperature of dominating σ phase is located in between 900-950 °C. Minor nitrides including π phase and Cr2N with the nose temperature of 900 °C and 850 °C, respectively, were detected after prolonged heat treatment times. Area fraction of precipitates was calculated by analyzing micrographic images in the software ImageJ. Charpy impact tests indicate that the impact toughness degrades with increasing area fraction of precipitates but at a higher rate at the early stage of precipitation. Despite a much-lessened area fraction, fine precipitates decorating the grain boundaries in a continuous pattern impose significant negative effect on impact toughness. Pitting corrosion resistance was indicated by critical pitting temperature (CPT) as per ASTM G150mod (3M MgCl2). Pitting corrosion resistance deteriorated with increasing amount of σ phase due to the Cr- and Mo-depleted surrounding area, but it is more dependent on the distribution pattern of precipitates, as well as the secondary phase type. The lowest CPTs were measured after heat treatment for 500 min at 800 °C and 850 °C where nitrides including Cr2N and π phase were formed and the small precipitates were distributed on grain boundaries continuously. Auxiliary simulation of TTT diagram via TC PRISMA shows drastic variation from experimental results in regard of time scale. The enhancement pre-factor for the interfacial mobility and interfacial energy can be modified to approach the experimental results. / Detta arbete utfördes för att undersöka fasomvandlingar och dess inflytande på slagsegheten och gropfrätningsmotståndet för det superaustenitiska rostfria stålet (SASS) SANICRO® 35. Ett tid-temperatur-transformationsdiagram (TTT-diagram) har tagits fram genom att utföra isotermiska värmebehandlingar mellan 650-1050 °C med olika hålltider från 5-500 minuter. Mikrostrukturanalys genom LOM-DIC, SEM-EDS undersökning visar att nosen för den dominerande σ-fasen ligger mellan 900-950 °C. Mindre nitrider, som π-fas och Cr2N, med nosarna vid 900 °C respektive 850 °C observerades vid längre hålltider. Areafraktionen av utskiljningar beräknades genom analys av mikrobilder med programmet ImageJ. Slagprovning visade att slagsegheten minskar med ökande fraktion utskiljningar men med en tydligare försämring i början av fastransformationen. Trots att de utgör en betydligt mindre areafraktion så kan mindre utskiljningar som följer korngränserna också påverka materialet signifikant negativt. Gropfrätningsmotståndet testades genom att mäta Critical Pitting Temperature (CPT) enligt ASTM G150mod (3M MgCl2). CPT minskade med ökande andel σ-fas p.g.a. den Cr- och Mo-utarmade zon som omger de utskilda partiklarna. Det finns även en stark koppling mellan lägre CPT och distributionen av utskiljningarna samt andra typer av faser. Lägst CPT uppmättes efter 500 minuter vid 800 °C och 850 °C då små nitrider inklusive Cr2N och π-fas bildats längs med stora delar av korngränserna. Simulering av TTT-diagram i TC PRISMA visade en drastisk skillnad i tiden till utskiljning/mängden utskiljningar jämfört med de experimentella resultaten. Diffusionförstärkningsfaktorn (eng. “mobility enhancement pre-factor”) och ytenergin kan minskas för att bättre överensstämma med de experimentella resultaten.
334

Microbial contamination in the surface water in the Ba Vi National Park, Ha Noi

Le, Nhu Da, Phung, Thi Xuan Binh, Le, Thi Phuong Quynh 07 February 2019 (has links)
Ba Vi National Park, one of 28 Vietnam National parks, is currently preserved and exploited for a variety of purposes, including the preservation of intact natural forest ecosystems and genetic resources of rare plants and animals. This paper presents the monitoring results of microbial contamination in surface water environment of the Ba Vi National Park (Ha Noi) in the period 2013-2014 and 2018. The results showed that total coliform (TC) density varied from 23 to 11,000 MPN/100ml in bimonthly observation in 2013-2014 which was lower than that one of sampling campaign in 2018, from 900 MPN/100ml to 8,100 MPN/ml. Fecal coliform (FC) densities vaired from 0 to 110 MPN/100ml in 2013 -2014 were lower than that in 2018, from 0 MPN/100ml to 600 MPN/100ml. At several observation time, both TC and FC were higher than the allowable values of the Vietnam national technical regulation QCVN 08-MT: 2015/BTNMT column A1 for surface water quality. The exceeded values of TC and FC than the allowable values and the increase trend from the 2013 to 2018 periods indicated the potential risks to the public health in this region when people use water for domestic and agricultural purposes. Our results provide dataset for environmental management in the Ba Vi National Park in order to protect the eco-environment in parallel with economical-social development. / Vườn Quốc gia Ba Vì, một trong 28 vườn quốc gia của Việt Nam hiện đang được bảo tồn và khai thác cho nhiều mục đích, trong đó có bảo tồn nguyên vẹn các hệ sinh thái rừng tự nhiên, các nguồn gen động, thực vật quý hiếm, các đặc sản rừng và các di tích lịch sử, cảnh quan tự nhiên trong vùng. Bài báo trình bày kết quả quan trắc, đánh giá mức độ ô nhiễm vi sinh vật trong môi trường nước mặt tại Vườn Quốc Gia Ba Vì, Hà Nội giai đoạn 2013-2014 và 2018. Kết quả cho thấy mật độ coliform tổng số (TC) biến đổi trong khoảng từ 23 – 11.000 MPN/100ml trong các đợt quan trắc định kỳ 2 tháng/lần trong hai năm 2013 - 2014 và trong khoảng từ 900 – 8.100 MPN/100ml trong một đợt quan trắc năm 2018. Mật độ fecal coliform (FC) biến đổi trong khoảng từ 0 - 110 MPN/100ml năm 2013 -2014 và từ 0 - 600 MPN/100ml vào năm 2018. Vào một số thời điểm quan trắc, mật độ FC và TC vượt giá trị cho phép của quy chuẩn kỹ thuật Quốc Gia QCVN 08-MT:2015/BTNMT cột A1 về chất lượng nước mặt. Các giá trị TC và FC vượt quá giá trị cho phép và xu hướng gia tăng TC và FC từ 2013 -2018 cho thấy nguy cơ tiềm tàng khi người dân sử dụng nguồn nước này cho các mục đích sinh hoạt và nông nghiệp. Như vậy, kết quả của nghiên cứu này nhấn mạnh nhu cầu giám sát thường xuyên chất lượng nước và cần thực hiện các giải pháp hiệu quả để xử lý và quản lý nguồn gây ô nhiễm trong khu vực nhằm bảo vệ môi trường sinh thái song song với phát triển kinh tế - xã hội của khu vực.
335

Strength in flexibility : research into innovative flexible bearing designs for wave convertor permanent magnet generators

Bedford, Adam January 2011 (has links)
Originally this research was to investigate the use of hydrostatic bearings in large linear machines, such as linear generators, and determine their viability in a power generation context. It quickly became clear that it was possible to make hydro-static bearings viable, however the methods employed to do so gave rise to new possibilities which altered the scope of the research. The overall aim of the research has become to look at flexible construction, using modular generation units, as a means of creating more reliable and cost effective generators. The methods employed to do this involved modularising the generator's structure. Each module then acts as a generator in its own right transferring its power to the parent machine. The potential for each module design was assessed based on its losses, due to the bearings, and its economic potential, such as how it impacted the operation and maintenance costs or transport costs and consideration of how each design affected the power density of the parent machine. The basic structural analysis showed that, of the arrangements tried, there was a distinct advantage to restricting the number of bearings because it reduces energy losses. This is particularly true of designs that take advantage of the MMA concepts. The magnitude of the forces within the generators, during operation, lead to the creation 2-stage bearing and MMA concepts. The key reasons for them being to reducing dynamic forces within the generator and increase tolerance to design flaws and damage. Reducing the dynamic forces reduces losses in all types of bearings improving overall efficiency. Not all the concepts present in this document show commercial promise, however from the basic principles used to understand their working, there are some whose potential is clear. In general the modules have reduced the weight necessary to operate a successful generator and reduced the bearing losses no matter the type of bearing being used. Predicted force reductions mean that less strength critical and more cost effective materials can be used in the machines construction. Given that the original scope of the research was to assess a single type of bearing it has come a long way to incorporate construction methods that will reduce operation and transport costs, as well as being more efficient on some of the construction materials. The final module designs show great promise to increase the power density of generators whilst making them easy to maintain. Although hydrostatic bearings provide excellent lubrication the basic analysis performed herein shows that their energy consumption exceeds the energy loss of normal roller bearings reducing overall generator efficiency. The modular constructions presented may not provide a great jump in efficiency over previous designs however they do show a way to simplify operation and maintenance costs improving overall commercial viability. All 3D/CAD models contained herein were created by the author for this work unless otherwise stated/referenced.
336

Spin injection into high temperature superconductor

Severac, Childerick Henri Louis January 2000 (has links)
No description available.
337

High temperature superconductors in electromagnetic applications

Richens, P. E. January 2000 (has links)
No description available.
338

Processing studies on Bi-2212 superconducting thick films

Balmer, B. R. January 2000 (has links)
No description available.
339

Avaliação volumétrica da fenda alveolar por meio de tomografia computadorizada por feixe cônico (TCFC) em pacientes com fissura labiopalatina / Volumetric assessement of the alveolar cleft using Cone Beam Computerized Tomography (CBCT) in patients with cleft lip and palate

Rocha, Marcos Antonio de Souza 16 May 2012 (has links)
A reabilitação dos pacientes com fissura de lábio e palato teve significativa evolução nas últimas décadas, sendo o desenvolvimento do enxerto ósseo alveolar muito importante para este avanço. É um procedimento que requer atenção rigorosa aos detalhes, por esta razão os exames de imagem são de grande auxílio. As Tomografias Computadorizadas enriqueceram os métodos de diagnóstico, despertando o interesse nos estudos desta modalidade de exame dentro da abordagem terapêutica da fissura labiopalatina. Este trabalho tem por objetivo desenvolver uma metodologia para avaliar o volume da fenda alvelar, por meio de Tomografia Computadorizada por Feixe Cônico. Utilizou-se o Software Open Source OsiriXTM DICOM Viewer Apple Inc, Versão 3.7.1 32 bits, um software de domínio público e que pode ser baixado gratuitamente na internet. Este software permite a visualização e manipulação de arquivos de tomografia computadorizada, desde de que os mesmos sejam salvos no formato DICOM, oferecendo possibilidade de mensuração tanto de medidas lineares, como de cálculo de área e de volume, sempre em proporções reais (1:1). A amostra foi constituída pelas imagens tomográficas de 30 pacientes, sendo 24 portadores de fissuras unilaterais e 6 de bilaterais, com idade média de 09 anos e 09 meses, sendo 19 do gênero masculino e 11 do feminino. Após a importação dos arquivos, foram utilizadas ferramentas do software OsiriXTM por 2 examinadores, em tempos distintos, para se proceder à mensuração do volume da fenda alveolar nos cortes axiais, a qual foi delimitada por meio da demarcação de pontos e limites pré-determinados. Foi realizada a análise pelo Teste da Estatística Alfa de Cronbach, que comprovou o elevado grau de reprodutibilidade e confiabilidade do método proposto (p<0,001). O volume médio encontrado foi de 0,92 ± 0,31 cm3, sendo que em relação aos tipos de fenda observou-se que as fissuras unilaterais apresentaram maior volume do que as bilaterais (p=0,019). Não houve diferenças quanto ao gênero, faixa etária e lado da fissura. Concluiu-se que o software OsiriXTM é eficiente em mensurar o volume da fenda alveolar; o método proposto pode ser reproduzido e o volume médio da fenda alveolar das fissuras unilaterais é maior que o das bilaterais. / Rehabilitation of patients with cleft lip and palate has evolved significantly in recent decades, due to development of the alveolar bone graft procedures. It is a procedure that requires strict attention to detail, and for this reason imaging exams are of great help. Computerized Tomography has enriched the diagnostic methods, arousing interest in studies of this method of examination in the therapeutic treatment of cleft lip and palate. This study aims to develop a methodology to assess the volume of the alveolar cleft, using Cone Beam Computerized Tomography. The 32-bit OsiriX® DICOM Viewer (Apple, Inc., version 3.7.1) open source softtware, a public domain program which can be downloaded for free from the Internet, was used. This software enables the visualization and manipulation of Computerized Tomography files as long as they are saved in the DICOM format, offering possibilities both for making linear measurements and also for calculating area and volume, always in real proportions (1:1). The sample was composed of tomographic images of 30 patients: 24 with unilateral and 6 with bilateral cleft , with average age of 9 years and 9 months, 19 male and 11 female. After importing the files, 2 examiners used tools from the OsiriXTM software, at different times, to measure the volume of the alveolar cleft lip and palate along the axial cuts, which was delimited using demarcation points and predetermined limits. Statistical analysis was performed using Cronbachs Alpha test, which demonstrated the high degree of reproducibility and reliability of the proposed method (p<0,001). The mean volume found was 0.92 ± 0.31 cm3 and, in relation to the type of cleft observed, the unilateral clefts presented larger volume than the bilaterals (p=0,019). There were no differences regarding gender, age range, and side of the cleft. It was concluded that the OsiriXTM software is efficient for measuring the volume of alveolar cleft; that the proposed method can be reproduced; and, that the mean volume of the alveolar unilateral cleft is greater than bilateral clefts.
340

Utilização de técnicas de análise de imagens para avaliação da morfologia interna de sementes de soja e milho / Use of image analysis techniques to evaluate the internal morphology of soybean and corn seeds

Capelaro, Lucas Sousa 30 January 2018 (has links)
Os testes utilizados rotineiramente na avaliação de danos mecânicos, danos causados por insetos e danos por deterioração de tecidos em sementes de soja e de milho são destrutivos, impossibilitando a associação dos resultados obtidos com os testes fisiológicos (germinação e vigor). Dessa forma, a avaliação da qualidade de sementes por meio de análise de imagens tem despertado interesse da pesquisa, devido ao fato de serem técnicas rápidas e não destrutivas, permitindo tal associação. Dentre as técnicas de análise de imagens existentes, as técnicas de microtomografia computadorizada de raios X (micro-TC) e imagem por ressonância magnética (IRM) tem se mostrado promissoras na pesquisa com sementes, por gerarem imagens tridimensionais, que permitem verificar, com precisão, a localização dos danos internos nas sementes. Assim, o objetivo deste trabalho foi utilizar as técnicas de micro-TC e IRM para avaliar danos internos em sementes de milho e de soja, verificar suas relações com a germinação e compará-las a técnica de raios X, que vem sendo utilizada na pesquisa com sementes. Para tanto foram selecionadas previamente, 32 sementes de soja e 30 sementes de milho, que foram submetidas aos testes de raios X, micro-TC e IRM, para obtenção das imagens e, posteriormente, ao teste de germinação, para associar os resultados obtidos com o desempenho das sementes. Pode-se concluir para as sementes de soja que as três técnicas se mostraram eficientes na detecção de danos nas sementes. Por outro lado, para as sementes de milho, pode-se haver necessidade de utilização das técnicas de micro-TC e IRM para avaliar, com maior precisão, a morfologia interna das sementes. / The current tests used in the evaluation of mechanical, insect, and tissue damage in soybean and corn seeds are destructive, making it impossible to associate those with the results obtained with physiological tests (germination and vigor).Therefore, evaluation of the seed quality by imaging analysis techniques aroused interest in seed research for being fast and non-destructive techniques, allowing association with physiological tests. X-ray computerized microtomography (micro-CT) and magnetic resonance imaging (MRI) seem promising techniques due to the fact they generate three-dimensional imagens allowing more accurately evaluation of the seed\'s internal morphology. The objective of this study was to use the micro-CT and MRI techniques to evaluate internal morphology of soybean and corn seeds, correlate their relationship with the physiological test (germination test) and to compare them with the X-ray technique, which has been used in seed research. For that 32 soybena seeds and 30 corn seeds were selected. Seeds were tested with X-ray, micro-CT, MRI, to obtain the images. Then germination test was conducted to associate the results obtained with the performance of the seeds. Overall, the three techniques were efficient in detecting damage in soybean seeds. On the other hand for corn, it may be necessary to use the micro-CT and MRI techniques to evaluate more accurately the internal morphology of the seeds.

Page generated in 0.025 seconds