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  • 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.
301

Envolvimento dos oncogenes BRAF, PIK3CA e AKT1 e do microRNA supressor de tumor let-7 na transformação maligna e progressão tumoral tiroidiana. / Involvement of BRAF, PIK3CA and AKT1 oncogenes and let-7 tumor supressor gene in malignant tranformation and progression oh thyroid cancer.

Júlio Cezar Marques Ricarte Filho 27 May 2009 (has links)
Neste estudo, geramos ensaios de espectrometria de massa para detecção de 111 mutações nos genes RET, BRAF, NRAS, HRAS, KRAS, PIK3CA e AKT1 e avaliamos inúmeras linhagens celulares e tumores tiroidianos. Mostramos que as mutações dos genes BRAF e RAS refletem prognósticos distintos e que as mutações BRAF são altamente prevalentes em câncer metastático. Mutações dos genes PIK3CA e AKT1, esta última sendo reportada pela primeira vez no câncer de tiróide, são relativamente frequentes neste câncer. Avaliamos ainda a função do microRNA let-7 neste câncer. Mostramos que a ativação do rearranjo RET/PTC3 em células de tiróide PCCl3 reduz a expressão de let-7. Além disso, a transfecção deste microRNA em células TPC-1, que apresentam o rearranjo RET/PTC1, inibe a fosforilação de ERK, o crescimento celular e modula a expressão de genes do ciclo celular e diferenciação. Estes dados contribuem na aplicação de terapias dirigidas a efetores das vias PI3K e MAPK no câncer de tiróide, além de salientar o envolvimento do miRNA let-7 como um gene supressor tumoral nesta doença. / In this study, we designed an assay panel for genotyping 111 mutations by mass spectrometry in RET, BRAF, NRAS, HRAS, KRAS, PIK3CA, AKT1 and other related genes in many thyroid cancer cell lines and tumors. We show that patients with BRAF and RAS mutations have distinct prognosis and that BRAF mutations are highly prevalent in metastatic thyroid cancers. Mutations of PIK3CA and AKT1, the latter not previously described in this disease, are comparatively frequent in thyroid cancers. In addition, we evaluated the role of let-7 microRNA in this cancer. We show that RET/PTC3 activation in PCCl3 thyroid cells reduces let-7 expression. Moreover, transfection of let-7 in TPC-1 cells, which harbor RET/PTC1 rearrangement, inhibits MAPK activation, reduces cell growth and modulates the expression of cell cycle and differentiation genes. These findings may contribute to the design of therapies directed at MAPK and PI3K effectors and to highlight the function of let-7 as tumor suppressor gene in thyroid cancer.
302

The effect of dimethyl sulfoxide on the induction of DNA strand breaks in plasmid DNA and colony formation of PC Cl3 mammalian cells by alpha-, beta-, and Auger electron emitters 223Ra, 188Re, and 99mTc

Runge, Roswitha, Oehme, Liane, Kotzerke, Jörg, Freudenberg, Robert 16 January 2017 (has links)
BACKGROUND: DNA damage occurs as a consequence of both direct and indirect effects of ionizing radiation. The severity of DNA damage depends on the physical characteristics of the radiation quality, e.g., the linear energy transfer (LET). There are still contrary findings regarding direct or indirect interactions of high-LET emitters with DNA. Our aim is to determine DNA damage and the effect on cellular survival induced by (223)Ra compared to (188)Re and (99m)Tc modulated by the radical scavenger dimethyl sulfoxide (DMSO). METHODS: Radioactive solutions of (223)Ra, (188)Re, or (99m)Tc were added to either plasmid DNA or to PC Cl3 cells in the absence or presence of DMSO. Following irradiation, single strand breaks (SSB) and double strand breaks (DSB) in plasmid DNA were analyzed by gel electrophoresis. To determine the radiosensitivity of the rat thyroid cell line (PC Cl3), survival curves were performed using the colony formation assay. RESULTS: Exposure to 120 Gy of (223)Ra, (188)Re, or (99m)Tc leads to maximal yields of SSB (80 %) in plasmid DNA. Irradiation with 540 Gy (223)Ra and 500 Gy (188)Re or (99m)Tc induced 40, 28, and 64 % linear plasmid conformations, respectively. DMSO prevented the SSB and DSB in a similar way for all radionuclides. However, with the α-emitter (223)Ra, a low level of DSB could not be prevented by DMSO. Irradiation of PC Cl3 cells with (223)Ra, (188)Re, and (99m)Tc pre-incubated with DMSO revealed enhanced survival fractions (SF) in comparison to treatment without DMSO. Protection factors (PF) were calculated using the fitted survival curves. These factors are 1.23 ± 0.04, 1.20 ± 0.19, and 1.34 ± 0.05 for (223)Ra, (188)Re, and (99m)Tc, respectively. CONCLUSIONS: For (223)Ra, as well as for (188)Re and (99m)Tc, dose-dependent radiation effects were found applicable for plasmid DNA and PC Cl3 cells. The radioprotection by DMSO was in the same range for high- and low-LET emitter. Overall, the results indicate the contribution of mainly indirect radiation effects for each of the radionuclides regarding DNA damage and cell survival. In summary, our findings may contribute to fundamental knowledge about the α-particle induced DNA damage.
303

Variable Relative Biological Effectiveness in Proton Treatment Planning

Hahn, Christian 17 August 2023 (has links)
Protonen töten Zellen wirksamer ab als Photonen. Die klinisch verwendete konstante relative biologische Wirksamkeit (RBW) für Protonen vernachlässigt jedoch erste klinische Evidenz einer RBW-Variabilität, die vom linearen Energietransfer (LET) abhängt. Diese Arbeit trägt dazu bei, die RBW-Variabilität in Protonen-Bestrahlungsplänen zu berücksichtigen, um potenzielle Nebenwirkungen zu vermindern. Zuerst wurde ein erhöhtes Risiko für RBW-induzierte Nebenwirkungen bei Hirntumorpatienten festgestellt. Dies konnte jedoch nicht systematisch durch klinische Planungsstrategien reduziert werden. Zweitens ergab eine multizentrische europäische Studie, dass die zentrums-spezifischen, nicht standardisierten LET-Berechnungen erheblich voneinander abweichen. Eine harmonisierte LET-Definition wurde vorgeschlagen und reduzierte die Variabilität zwischen den Zentren auf ein klinisch akzeptables Niveau, was künftig eine einheitliche Dokumentation des Therapieergebnisses ermöglicht. Abschließend wurden vier Strategien zur RBW-Reduktion in der Planoptimierung bei Hirntumorpatienten angewandt, die das Risiko für Nekrose und Erblindung erheblich reduzierten. LET-Optimierung in Hochdosisregionen erscheint besonders geeignet, um die Sicherheit der Patientenbehandlung künftig weiter zu verbessern.:List of Figures vii List of Tables viii List of Acronyms and Abbreviations ix 1 Introduction 1 2 Theoretical background 3 2.1 Proton interactions with matter 4 2.2 Biological effect of radiation 8 2.2.1 Linear-quadratic model 8 2.2.2 Relative biological effectiveness 9 2.3 Proton beam delivery and field formation 13 2.4 Treatment planning 14 2.4.1 Patient modelling and structure definition 15 2.4.2 Treatment plan optimisation 16 2.4.3 Treatment plan evaluation 19 2.5 Proton therapy uncertainties and mitigation strategies 22 2.5.1 Clinical mitigation strategies 23 2.5.2 Optimisation approaches beyond absorbed dose 26 3 Variable biological effectiveness in PBS treatment plans 29 3.1 LET and RBE recalculations of proton treatment plans with RayStation 30 3.1.1 Monte Carlo dose engine 30 3.1.2 Monte Carlo scoring extensions 32 3.1.3 Graphical user interface 33 3.2 LET assessment and the role of range uncertainties 36 3.2.1 Patient cohort and treatment plan creation 37 3.2.2 Simulation of range deviations 38 3.2.3 Treatment plan recalculation settings 39 3.2.4 Resulting impact of range deviations 40 3.3 Patient recalculations in case of side effects 46 3.3.1 Image registration and range prediction 48 3.3.2 Retrospective treatment plan assessment 49 3.4 Benefit of an additional treatment field 50 3.4.1 Patient and treatment plan information 50 3.4.2 Results of variable RBE recalculations 51 3.5 Discussion 51 3.6 Summary 59 4 Status of LET and RBE calculations in European proton therapy 61 4.1 Study design 62 4.1.1 Treatment planning information 64 4.1.2 Data processing and treatment plan evaluation 67 4.2 Treatment plan comparisons in the water phantom 68 4.2.1 Absorbed dose evaluation 69 4.2.2 Centre-specific LET calculations 69 4.2.3 Harmonised LET calculations 71 4.3 Treatment plan comparisons in patient cases 72 4.3.1 Dose-averaged linear energy transfer for protons 73 4.3.2 Centre-specific RBE models and parameters 76 4.4 Discussion 77 4.5 Summary 82 5 Biological treatment plan optimisation 83 5.1 Treatment plan design 84 5.1.1 Clinical goals 86 5.1.2 Novel treatment plan optimisation approaches 87 5.2 Treatment plan quality assessment with a constant RBE 90 5.3 Assessment of NTCP reductions with a variable RBE 90 5.4 Discussion 95 5.5 Conclusion 100 6 Summary 103 7 Zusammenfassung 107 Bibliography 111 Danksagung 137 / Protons are more effective in cell killing than photons. However, the clinically applied constant proton relative biological effectiveness (RBE) neglects emerging clinical evidence for RBE variability driven by the linear energy transfer (LET). This thesis aims to safely account for RBE variability in proton treatment plans to mitigate potential side effects. First, an elevated risk for RBE induced overdosage was found in brain tumour patients. However, this could not be mitigated systematically by clinical planning strategies. Second, a multicentric European study revealed that centre-specific non-standardised LET calculations differed substantially. A harmonised LET definition was proposed which reduced the inter-centre variability to a clinically acceptable level and allows for future consistent outcome reporting. Finally, four strategies to include RBE variability in treatment plan optimisation were applied to brain tumour patients, which considerably reduced the estimated risk for necrosis and blindness. Of these, LET optimisation in high dose regions may be suited for clinical practice to further enhance patient safety in view of a variable RBE.:List of Figures vii List of Tables viii List of Acronyms and Abbreviations ix 1 Introduction 1 2 Theoretical background 3 2.1 Proton interactions with matter 4 2.2 Biological effect of radiation 8 2.2.1 Linear-quadratic model 8 2.2.2 Relative biological effectiveness 9 2.3 Proton beam delivery and field formation 13 2.4 Treatment planning 14 2.4.1 Patient modelling and structure definition 15 2.4.2 Treatment plan optimisation 16 2.4.3 Treatment plan evaluation 19 2.5 Proton therapy uncertainties and mitigation strategies 22 2.5.1 Clinical mitigation strategies 23 2.5.2 Optimisation approaches beyond absorbed dose 26 3 Variable biological effectiveness in PBS treatment plans 29 3.1 LET and RBE recalculations of proton treatment plans with RayStation 30 3.1.1 Monte Carlo dose engine 30 3.1.2 Monte Carlo scoring extensions 32 3.1.3 Graphical user interface 33 3.2 LET assessment and the role of range uncertainties 36 3.2.1 Patient cohort and treatment plan creation 37 3.2.2 Simulation of range deviations 38 3.2.3 Treatment plan recalculation settings 39 3.2.4 Resulting impact of range deviations 40 3.3 Patient recalculations in case of side effects 46 3.3.1 Image registration and range prediction 48 3.3.2 Retrospective treatment plan assessment 49 3.4 Benefit of an additional treatment field 50 3.4.1 Patient and treatment plan information 50 3.4.2 Results of variable RBE recalculations 51 3.5 Discussion 51 3.6 Summary 59 4 Status of LET and RBE calculations in European proton therapy 61 4.1 Study design 62 4.1.1 Treatment planning information 64 4.1.2 Data processing and treatment plan evaluation 67 4.2 Treatment plan comparisons in the water phantom 68 4.2.1 Absorbed dose evaluation 69 4.2.2 Centre-specific LET calculations 69 4.2.3 Harmonised LET calculations 71 4.3 Treatment plan comparisons in patient cases 72 4.3.1 Dose-averaged linear energy transfer for protons 73 4.3.2 Centre-specific RBE models and parameters 76 4.4 Discussion 77 4.5 Summary 82 5 Biological treatment plan optimisation 83 5.1 Treatment plan design 84 5.1.1 Clinical goals 86 5.1.2 Novel treatment plan optimisation approaches 87 5.2 Treatment plan quality assessment with a constant RBE 90 5.3 Assessment of NTCP reductions with a variable RBE 90 5.4 Discussion 95 5.5 Conclusion 100 6 Summary 103 7 Zusammenfassung 107 Bibliography 111 Danksagung 137
304

«Sens e Razos d'una Escriptura»: edizione e studio della traduzione Occitana dell'Evangelium Nicodemi = «Sens e Razos d'una Escriptura»: édition et étude de la traduction Occitane de l'Evangelium Nicodemi

Collura, Alessio January 2014 (has links)
La tesi fornisce la prima edizione critica commentata del poema occitano 'Sens e razos d'una escriptura', il cosiddetto Vangelo occitano di Nicodemo. Si tratta di un testo in couplets d'octosyllabes, di origine linguadociana orientale e attribuibile, verosimilmente, agli anni '80/'90 del XIII secolo. Un'ampia introduzione di carattere storico-letterario, filologico e codicologico anticipa l'edizione stessa (corredata da traduzione in italiano) e fornisce un primo tentativo di contestualizzazione del testo.
305

Názory a postoje pohybově neúspěšných žáků mladšího školního věku k pohybovým aktivitám / Opinions and Attitudes of Unsuccessfully Moving Younger School Age Children toward Physical Activities

Vachová, Kateřina January 2011 (has links)
Diploma thesis title: Opinions and Attitudes of Unsuccessfully Moving Younger School Age Children toward Physical Activities Aims (goals): The main aim of the diploma thesis was to state opinions and attitudes of unsuccessfully moving younger-school-age children toward physical activities. Another aim was to create an overview of terms regarding the movement failure in the theoretical part. Further aim was to compare the opinions and attitudes of so defined children toward the physical activities to results of Kaplan (2001) and Holický (2011) and to monitor anthropometric characteristics of observed files. Methodology: The work was developed by using the method of Kaplan's research (2011). The research identified unsuccessfully moving children using a motoric testing. With this procedure the files for the subsequent determination of the characteristics of the unsuccessfully moving children were defined. Then, two types of questionnaires were used to research the opinions and attitude of the children toward the physical activities. Results: The results revealed the unsuccessfully moving children do a physical activity three times a week and occasionally. The pupils of the S2 file spend most of the time inactively, for instance by engaging themselves in computer activities or garden games. The group...
306

Problémy trestního soudnictví nad mládeží / The issues of juvenile criminal justice

Šípal, Jan January 2019 (has links)
1 The Issues of Juvenile Criminal Justice The Abstract This Master's degree thesis named "The Issues of Juvenile Criminal Justice" focuses on the issues of proceedings in the matters of children under the age of fifteen according to title third of the Act No. 218/2003 Coll. on the Responsibility of Juveniles for illegal Acts and on the Justice of Youth (hereinafter "ZSM"). These proceedings are unlike any other in that regard that although they are civil, they can't deny their penal aspect since they deal with the other offences, the acts which posses every element of a crime except for the fact that they were committed by someone not criminally liable. These proceedings are yet to be thoroughly examined by law literature or any other thesis and their statutory regulation itself is quite brief, that is despite the complexity of said issues. The first introductory chapter defines several basic concepts of these proceedings, such as "the child under the age of fifteen" or "other offence." Then, the ZSM is covered. This act is naturally crucial for the issue, though his relations to general civil and penal regulation must be explained. In the second chapter, called "Historical context," some key historical milestones are remembered, with the focus on Act No. 48/1931 Coll. on the Penal Justice System of the...
307

Exploring the Implementation of Cloud Security to Minimize Electronic Health Records Cyberattacks

Tyler, Lamonte Bryant 01 January 2018 (has links)
Health care leaders lack the strategies to implement cloud security for electronic medical records to prevent a breach of patient data. The purpose of this qualitative case study was to explore strategies senior information technology leaders in the healthcare industry use to implement cloud security to minimize electronic health record cyberattacks. The theory supporting this study was routine activities theory. Routine activities theory is a theory of criminal events that can be applied to technology. The study's population consisted of senior information technology leaders from a medical facility in a large northeastern city. Data collection included semistructured interviews, phone interviews, and analysis of organizational documents. The use of member checking and methodological triangulation increased the validity of this study's findings among all participants. There were 5 major themes that emerged from the study (a) requirement of coordination with the electronic health record vendor and the private cloud vendor, (b) protection of the organization, (c) requirements based on government and organizational regulations, (d) access management, (e) a focus on continuous improvement. The results of this study may create awareness of the necessity to secure electronic health records in the cloud to minimize cyberattacks. Cloud security is essential because of its social impact on the ability to protect confidential data and information. The results of this study will further serve as a foundation for positive social change by increasing awareness in support of the implementation of electronic health record cloud security.
308

Role of Non-Homologous End-Joining in Repair of Radiation-Induced DNA Double-Strand Breaks

Karlsson, Karin January 2006 (has links)
<p>Efficient and correct repair of DNA damage, especially DNA double-strand breaks (DSBs), is vital for the survival of individual cells and organisms. Defects in the DNA repair may lead to cell death or genomic instability and development of cancer. </p><p>The repair of DSBs in cell lines with different DSB rejoining capabilities was studied after exposure to ionising radiation. A new cell lysis protocol performed at 0ºC, which prevents the inclusion of non-true DSBs in the quantification of DSBs by pulsed-field gel electrophoresis (PFGE), was developed. Results showed that when the standard protocol at 50ºC was used, 30-40% of the initial yield of DSBs corresponds to artifactual DSBs. The lesions transformed to DSBs during incubation at 50ºC were repaired within 60-90 minutes <i>in vivo</i> and the repair was independent of DNA-PK, XRCC1 and PARP-1.</p><p>Non-homologous end-joining (NHEJ) is the major DSB repair pathway in mammalian cells. We show that DSBs are processed into long single-stranded DNA (ssDNA) ends after ≥1 h of repair in NHEJ deficient cells. The ssDNA was formed outside of the G<sub>1</sub> phase of the cell cycle and only in the absence of the NHEJ proteins DNA-PK and DNA Ligase IV/XRCC4. The generation of ssDNA had great influence on the quantification of DSBs by PFGE. The standard protocol caused hybridisation of the ssDNA ends, resulting in overestimation of the DSB repair capability in NHEJ deficient cells.</p><p>DSBs were also quantified by detection of phosphorylated H2AX (γ-H2AX) foci. A large number of γ-H2AX foci still remaining after 21 h of repair in an NHEJ deficient cell line confirmed the low repair capability determined by PFGE. Furthermore, in normal cells difficulty in repairing clustered breaks was observed as a large fraction of γ-H2AX foci remaining 24 h after irradiation with high-LET ions.</p>
309

Role of Non-Homologous End-Joining in Repair of Radiation-Induced DNA Double-Strand Breaks

Karlsson, Karin January 2006 (has links)
Efficient and correct repair of DNA damage, especially DNA double-strand breaks (DSBs), is vital for the survival of individual cells and organisms. Defects in the DNA repair may lead to cell death or genomic instability and development of cancer. The repair of DSBs in cell lines with different DSB rejoining capabilities was studied after exposure to ionising radiation. A new cell lysis protocol performed at 0ºC, which prevents the inclusion of non-true DSBs in the quantification of DSBs by pulsed-field gel electrophoresis (PFGE), was developed. Results showed that when the standard protocol at 50ºC was used, 30-40% of the initial yield of DSBs corresponds to artifactual DSBs. The lesions transformed to DSBs during incubation at 50ºC were repaired within 60-90 minutes in vivo and the repair was independent of DNA-PK, XRCC1 and PARP-1. Non-homologous end-joining (NHEJ) is the major DSB repair pathway in mammalian cells. We show that DSBs are processed into long single-stranded DNA (ssDNA) ends after ≥1 h of repair in NHEJ deficient cells. The ssDNA was formed outside of the G1 phase of the cell cycle and only in the absence of the NHEJ proteins DNA-PK and DNA Ligase IV/XRCC4. The generation of ssDNA had great influence on the quantification of DSBs by PFGE. The standard protocol caused hybridisation of the ssDNA ends, resulting in overestimation of the DSB repair capability in NHEJ deficient cells. DSBs were also quantified by detection of phosphorylated H2AX (γ-H2AX) foci. A large number of γ-H2AX foci still remaining after 21 h of repair in an NHEJ deficient cell line confirmed the low repair capability determined by PFGE. Furthermore, in normal cells difficulty in repairing clustered breaks was observed as a large fraction of γ-H2AX foci remaining 24 h after irradiation with high-LET ions.
310

L'influenza dell'estetica crociana nelle riviste di critica letteraria nei primi 50 anni del novecento / The Croce Aesthetics' Influence in Literary Critical Rewieves in the First 50 Years of 1900

VIGANO' , OMAR 23 February 2007 (has links)
Nel sistema di Croce l'Estetica costituisce il primario fondamento, e nella sua auroralità eccede per aver trovato immediata declinazione, e crescita nella critica letteraria, attraverso la redazione della rivista la critica; determinando la rapida e diffusa infiltrazione dei suoi principi nel terreno della cultura artistica nazionale. ma importare le conquiste filosofiche nella critica letteraria, vuol dire anche trasferirne le problematiche aperte. Serra, Cecchi, de Robertis e Boine sulla Voce avanzano l'esigenza di un superamento; Russo, Levi e Capasso sono esempi del difficile accordo o del contrasto di una critica storica e stilistica con l'estetica di Croce. Anche la critica musicale e figurativa provano uno sviluppo decisivo nella spinta dell'idealismo. l'influenza è circolare: i motivi generati dalle rassegne spingono croce a riformulare la propria estetica nella Poesia del 1936. / Estetica (Aesthetics) is the primary foundation of Croce's system, and in auroral (auroralita') character it excels for having discovered his immediate inflexion, confirmation and growth into the literary criticism through the redaction of the review La Critica; causing the quick and widespread diffusion of his principles into the national artistic culture. Importing philosophic pursuits in literary criticism means also transfer deep problems. Serra, Cecchi, De Robertis and Boine in the review Voce push for the downfall of Croce's thought; Russo, Levi and Capasso are examples of the opposition of a historicist and stylistic criticism with Croce's aesthetics. The music and art criticism demonstrate also a decisive development with an idealistic thrust. The influence is circular: the critiques coming from reviews urge Croce to re-formulate his own aesthetics that was in his 1936 work Poesia.

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