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Lung cancer is the leading cause of cancer deaths worldwide. A large part of this high mortality rate is due to the onset of metastatic disease prior to diagnosis. Advances in treatment for metastatic disease may be achieved by understanding more about the identity of metastatic tumor cells and the mechanisms those cells employ to spread throughout the body. This thesis examined the relationship between cells capable of tumor propagation upon serial transplantation (tumor-propagating cells, or TPCs) and those with metastatic potential.

This thesis describes experimental investigation of thermal and combustion phenomena as well as structure for self- propagating combustion synthesis of porous Ni - Ti intermetallic aimed for structural biomedical application. The control parameters for the porosity distribution have been investigated experimentally through varying the preheat temperature, initial porosity, initial elemental particle size, and applied pressure during the fabrication process. Ni and Ti elemental powders are mixed using a 1:1 ratio. The mixture is compressed using several different compression forces to produce cylindrical samples of 1.1 cm diameter and 2-3cm length, with initial porosity ranging from 30% to 40%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downwards. The combustion reaction is recorded with a motion camera. An infrared sensor is used to record the temperature profile during the combustion process. The samples are then cut using a diamond saw in both longitudinal and transverse directions. Image analysis software is then used to analyze the porosity distribution in each sample.

In the last decades, computational models have become useful tools for studying biological neural networks. These models are typically constrained by either behavioural data from neuropsychological studies or by biological data from neuroscience. One model of the latter kind is the Bayesian Confidence Propagating Neural Network (BCPNN) - an attractor network with a Bayesian learning rule which has been proposed as a model for various types of memory. In this thesis, I have further studied the potential of the BCPNN in short-term sequential memory. More specifically, I have investigated if the network can be used to qualitatively replicate behaviours of immediate verbal serial recall, and thereby offer insight into the network-level mechanisms which give rise to these behaviours. The simulations showed that the model was able to reproduce various benchmark effects such as the word length and irrelevant speech effects. It could also simulate the bow shaped positional accuracy curve as well as some backward recall if the to-be recalled sequence was short enough. Finally, the model showed some ability to handle sequences with repeated patterns. However, the current model architecture was not sufficient for simulating the effects of rhythm such as temporally grouping the inputs or stressing a specific element in the sequence. Overall, even though the model is not complete, it showed promising results as a tool for investigating biological memory and it could explain various benchmark behaviours in immediate serial recall through neuroscientifically inspired learning rules and architecture. / Under de senaste årtionden har datorsimulationer blivit ett allt mer populärt verktyg för att undersöka biologiska neurala nätverk. Dessa modeller är vanligtvis inspirerade av antingen beteendedata från neuropsykologiska studier eller av biologisk data från neurovetenskapen. En modell av den senare typen är ett Bayesian Confidence Propagating Neural Network (BCPNN) - ett autoassociativt nätverk med en Bayesiansk inlärningsregel, vilket tidigare har använts för att modellera flera typer av minne. I det här examensarbetet har jag vidare undersökt om nätverket kan användas som en modell för sekventiellt korttidsminne genom att undersöka dess förmåga att replikera beteenden inom verbalt sekventiellt korttidsminne. Experimenten visade att modellen kunde simulera ett flertal viktiga nyckeleffekter såsom the word length effect och the irrelevant speech effect. Däröver kunde modellen även simulera den bågformade kurvan som beskriver andelen lyckade repetitioner som en funktion av position, och den kunde dessutom repetera korta sekvenser baklänges. Modellen visade också på viss förmåga att hantera sekvenser där ett element återkom senare i sekvensen. Den nuvarande modellen var däremot inte tillräcklig för att simulera effekterna som tillkommer av rytm, såsom temporär gruppering eller en betoning på specifika element i sekvensen. I sin helhet ser modellen däremot lovande ut, även om den inte är fullständig i sin nuvarande form, då den kunde simulera ett flertal viktiga nyckeleffekter och förklara dessa med hjälp av neurovetenskapligt inspirerade inlärningsregler.

Approved for public release, distribution is unlimited / Vertically propagating waves (VPWs) generated by prominent mountain ridges are a severe hazard to military aircraft operations. Properly forecasting the initiation and duration of such a phenomenon is critical, yet quite often missed by turbulence forecasters. A primary reason for poor forecast skill is vague VPW forecasting guidelines at the Air Force operational centers, focusing a majority of attention on the less severe, more common trapped lee wave response. The United States Air Forces in Europe Operational Weather Squadron (USAFE OWS) has requested a tool to aid in improving forecast ability of VPW events. Satellite analysis from October 2003 through March 2004 indicated an occurrence of six major VPW events to the lee of the Alps. Actual verification of turbulence in each VPW was unavailable due to the minimal pilot report (PIREP) database kept for military flights over Europe, therefore, a subjective assessment of turbulent conditions was determined depending on the resulting cloud signature. Using NCEP GFS model analysis and upstream upper air soundings during these events, an average synoptic condition and critical weather parameters were created. These developed tools were then tested from October 2004 through March 2005 to prove their reliability. In a limited data set these tools identified all VPW events, with only a 25% false alarm rate. This is compared to a 6% forecast ability with 0% false alarm rate determined during the 2003-2004 winter season by USAFE OWS forecasters. These new rules should be valuable in that they will provide a much needed capability for synoptic scale turbulence forecasters to better determine hazardous aviation conditions associated with VPWs. / Captain, United States Air Force

Buckle arrestors are devices placed along an offshore pipeline for the purpose of arresting an incoming propagating buckle. Typically, buckle arrestors locally increase the pipe’s bending rigidity in the hoop direction. Spiral buckle arrestors are rods closely wound around the pipe for a number of turns and then welded at the ends to secure it in place. Spiral buckle arrestor have some key advantages to other designs in that they provide limited resistance to axial bending of the pipeline, and they can be wound on a continuous line away from free ends. This thesis uses a combination of experiments and modeling to study the effectiveness of spiral buckle arrestors. A series of experiments are conducted using 1.25-inch diameter SS-304 tubes with diameter-to-thickness ratios of 19 and 25. Stainless steel rods of four diameters are wound on tubes for a chosen number of turns and secured in place. A propagating buckle is subsequently initiated in the tube, engages the arrestor quasi-statically, is temporarily arrested, and eventually crosses the arrestor at a pressure defined as the crossover pressure. The crossover pressure was found to depend on the tube D/t and mechanical properties; and the rod diameter, number of turns, and mechanical properties. Finite element models are developed that enable the simulation of rod winding, buckle propagation, and buckle crossover. Local collapse is induced by external pressure and is propagated quasi-statically until it engages the arrestor. The pressure is increased until the buckle crosses the arrestor. The model is shown to reproduce the experimental observations and a large number of the measured crossover pressures with sufficient accuracy. Additional simulations were performed varying the rod diameter, numbers of turns, and tube D/t in order to enrich the database developed. This database was subsequently used to develop an empirical design formula for the arresting efficiency based on key nondimensional parameters of the problem. As was the case for the slip-on buckle arrestor, the arresting efficiency is bounded by the confined propagation pressure of the pipe. / text

Darbe atlikta realiame gyvenime pasireiškiančio agresyvaus elgesio ir televizijoje rodomo smurto santykio analizė. Iškeltos hipotezės: • Nepilnamečių žiūrimos laidos ir filmai per TV skatina agresyvų elgesį. • Linkę nusižengti elgesio normoms nepilnamečiai, skirtingai nuo besilaikančių nustatytų elgesio normų nepilnamečių, dažniau TV programoje renkasi laidas, kuriose yra smurto. Naudojant anketinės grupinės apklausos, stebėjimo, nestruktūrizuoto interviu metodus trimis etapais buvo atliktas tyrimas, kurio tikslas - ištirti televizijos laidų poveikį 11-14 metų paauglių agresyviam elgesiui. Atlikta statistinė (aprašomoji koreliacijos, vidurkių) ir kontent duomenų analizė. Tyrime dalyvavo 150 Šiaulių Aukštabalio vidurinės mokyklos bei 150 (Šiaulių ir Kelmės) moksleivi���, įtrauktų į policiją dominančių vaikų įskaitą dėl padarytos nusikalstamos veikos. Empirinėje dalyje nagrinėjami paauglių televizoriaus žiūrėjimo ir programų pasirinkimo motyvai, lyginama ar linkę nusižengti elgesio normoms nepilnamečiai ir besilaikantys elgesio normų nepilnamečiai renkasi tuos pačius filmus ir TV laidas, analizuojama kiek moksleivių pasirinktose laidose yra agresyvaus elgesio, aiškinamasi kokią prasmę vaikai suteikia smurto fenomenui televizijoje. Svarbiausios empirinio tyrimo išvados: 1. Atlikus tyrimą paaiškėjo, kad neigiamas smurto žiniasklaidoje poveikis nepilnamečiams neabejotinai egzistuoja, stebimi Banduros įvardinti elgesio modelių išmokimo bei įsiminimo procesai. Susilpnėjus... [toliau žr. visą tekstą] / The analysis of relationship between aggressive behaviour asserting in real life and violence shown on television is made in work. The following hypotheses were formed: • The broadcasts and films watched by juveniles on television stimulate aggressive behaviour. • Juveniles who are minded to breach of decency, differently than those keeping moral norms, more often choose broadcasts in television programmes, where violence is shown. Using the methods of group questionnaire survey, observation, non structural interview the research was performed in three stages. The aim of this research – to investigate the influence of television broadcasts on the aggressive behaviour of teenagers of 11 – 14 years. The statistical (descriptive correlation, averages) and content data analyses were performed. 150 pupils of Siauliai Aukstabalio secondary school and 150 pupils (from Siauliai and Kelme), who are listed in register of children about which police is concerned due to their accomplished delinquent activity, participated in the research. In empiric part the motives of juveniles’ watching of television and choosing programmes are examined, compared whether juveniles who are minded to breach of decency and those keeping moral norms choose the same films and television broadcasts, analyzed how many aggressive behaviour is shown in them, explained what meaning do the children give to the phenomenon of violence in television. The most important conclusions of the empiric research: 1. After... [to full text]

<p>During development, the precise regulation of the processes of proliferation, migration, and differentiation is required to establish proper organ structure and function and to prevent the deregulation that can lead to disease, such as cancer. Improved understanding of the signals that regulate these processes is therefore necessary to both gain insight into the mechanisms by which organ development proceeds and to identify strategies for treating the consequences of deregulation of these processes. In the cerebellum, some of the factors that regulate these processes have been identified but remain incompletely understood. Our studies have focused on the signals that regulate the migration of cerebellar granule neuron progenitors (GNPs) and the contribution of the SDF-1/CXCR4 signaling axis to postnatal cerebellar development. Using conditional knockout mice to delete CXCR4 specifically in GNPs, we show that loss of CXCR4 results in premature migration of a subset of GNPs throughout postnatal development that are capable of proliferation and survival outside of their normal mitogenic niche. Loss of CXCR4 also causes a reduction in the activity of the Sonic hedgehog (SHH) pathway (the primary mitogen for GNPs) but does not affect GNP proliferation, differentiation, or capacity for tumor formation. Our data suggest that while other factors likely contribute, SDF-1/CXCR4 signaling is necessary for proper migration of GNPs throughout cerebellar development. </p><p>In addition to understanding the signals that regulate normal development, the identification of vulnerabilities of established tumors is also necessary to improve cancer treatment. One strategy to improve treatment involves targeting the cells that are critical for maintaining tumor growth, known as tumor-propagating cells (TPCs). In the context of the cerebellar tumor medulloblastoma (MB), we have previously identified a population of TPCs in tumors from patched mutant mice that express the cell surface carbohydrate antigen CD15/SSEA-1. Here, we employed multiple approaches in an effort to target these cells, including a biochemical approach to identify molecules that carry the CD15 carbohydrate epitope as well as an immunotoxin approach to specifically target CD15-expressing cells. Unfortunately, these strategies were ultimately unsuccessful, but an alternative approach that recognized a vulnerability of CD15+ cells was identified. We show that CD15+ cells express elevated levels of genes associated with the G2/M phases of the cell cycle, progress more rapidly through the cell cycle than CD15- cells, and contain an increased proportion of cells in G2/M. Exposure of tumor cells to inhibitors of Aurora and Polo-like kinases, key regulators of G2/M, induces cell cycle arrest, apoptosis and enhanced sensitivity to conventional chemotherapy, and treatment of tumor-bearing mice with these agents significantly inhibits tumor progression. Importantly, cells from human patient-derived MB xenografts are also sensitive to Aurora and Polo-like kinase inhibitors. Our findings suggest that targeting G2/M regulators may represent a novel approach for the treatment of human MB.</p> / Dissertation

Thesis (Ph. D.)--University of Nevada, Reno, 2008. / "December 2008." Includes bibliographical references (leaves 161-173). Online version available on the World Wide Web.

With the increase in and more diverse applications of microwave radio communications, the probability of a signal propagating through a medium of vegetation is increased. As a direct result of this demand for microwave communication systems, knowledge is required of the effects of vegetation media on the propagating microwave signal. This enables radio system planners to predict the signal loss more accurately, necessitating a detailed study of the propagation effects of vegetation. A vegetation depth attenuation model has been developed based on the International Telecommunications Union-Radio Sector model and validated against measurements conducted at two microwave frequencies of 11.2 GHz and 20 GHz. The measurements were conducted on a number of sites of differing geometries at different times of the year to obtain the two extreme states of foliage, in- and out-of-leaf. The trees found at the sites were of a number of indigenous species. A variety of species and environments were employed for the outdoor measurements as it was felt that any variation in the signal, occurring as a direct result of the species, climate, environment etc., would be reduced. A further study has been conducted in an anechoic chamber, the purpose being to investigate the depolarising effect of vegetation, to characterise and to ascertain how and to what extent the polarisation of the incident signal is changed as it passes through the vegetation without the effects of climate, location and environment affecting the resultant signal. To enable larger quantities of data to be obtained, collated and subsequently analysed and also to remove any scope for error during the collection of results, two data acquisition programs were written for the two main environments in which the measurements were to be undertaken, that is to say, outdoor and indoor (anechoic chamber) environments. In seeking to provide a model for the prediction of attenuation a radio wave will suffer as it is propagated through a body of vegetation, several models have been examined in turn and their relative merits discussed together with their applicability to the study. After examining the possible models available, the thesis provides a model which enables the prediction of additional attenuation a radiowave signal will suffer as a function of path length (depth) of the vegetation medium and frequency. The model can be recommended for use in the 10-30 GHz band. The study on the depolarisation of signals by vegetation has shown that the components of a vegetation medium e.g. tree trunks, branches and leaves, can cause considerable changes in the polarisation of the incident signal as it propagates through a volume of vegetation. The work presented in this thesis contains new measured results of the polarisation state of the radio wave as it emerges from a vegetation specimen. These results obtained in an anechoic chamber under controlled conditions have demonstrated that additional effects, other than attenuation by absorption and scatter need to be considered in order to characterise and subsequently model the overall effect of vegetation in the radio path of propagating signals.