Development of a small animal conformal irradiator with dual energy x-ray computed tomography imaging for kilovoltage dosimetry

External beam radiotherapy has become technically sophisticated with image guided radiation therapy (IGRT) and intensity modulated radiation therapy (IMRT). These technologies allow for precise delivery of radiation to geometric targets in cancer patients. However, many questions remain on how to best define targets based on biological information, such as functional imaging, and how to combine radiation with other cancer therapies. To help answer these questions, small animal preclinical studies are needed to generate data to inform clinical trials. However, the precise radiation delivery capabilities of IGRT and IMRT have not been available in the preclinical labs. To enable translational experiments and to address the lack of preclinical radiotherapy technology, a commercial micro-CT was first developed into an image-guided conformal radiotherapy system in this thesis. Computerized asymmetric jaws were constructed, implemented and characterized for the system. A Monte Carlo dose calculation package was successfully configured for the system and verified with film measurements. Respiratory gated imaging and radiotherapy was demonstrated with a phantom and in animals. Secondly, accurate radiation dosimetry reduces uncertainties in preclinical experiments. To achieve accurate dose calculations in the kilovoltage x-ray range where photoelectric effects and Compton scattering dominate, knowledge of material composition and density is needed. Dual energy micro-CT was optimized (including choice of x-ray beam peak voltages, filtrations, and duration) and evaluated for the purpose of characterizing materials. Dual energy CT techniques developed for clinical scanners were adapted and examined for micro-CT. A set of micro-CT phantoms consisting of 11 plastic materials and solutions that spanned a relevant range of compositions was designed and constructed. Initial experiments found beam-hardening image artefacts limited accurate measurements. By switching to a more sensitive detector, x-ray spectra with additional beam filtration were possible and resulted in reduced beam-hardening effects. This improved dual energy micro-CT measurement accuracy of material composition and density. In conclusion, a small animal image-guided conformal radiotherapy system was developed and commissioned for preclinical studies. Dual energy micro-CT was demonstrated as a method to characterize materials to improve kilovoltage dose calculation. This integrated micro-CT based small animal image-guided radiation platform has enabled numerous pre-clinical studies

How Well Does "Core" CPI Capture Permanent Price Changes?

We decompose core CPI and the food and energy CPI measures into permanent and transitory components using a correlated unobserved components model, to examine the behavior of core CPI when subject to shocks and to examine the claim that core CPI captures the persistent part of headline CPI. We find that the permanent component of core CPI is more volatile than core CPI, or that the permanent and transitory components are highly correlated. We find that the excluded food and energy components have important permanent components, and that core CPI has an important transitory component. We examine impulse response functions and find that headline CPI inflation responds more sharply to shocks than core CPI inflation, and after the first year the impact of shocks on headline inflation is less than the impact on core inflation.unobserved components, CPI, price indices, inflation, core

Secretory phospholipase A2-IIA in Alzheimer's disease and inflammatory responses in astrocytes

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on March 25, 2010).Vita.Thesis advisor: Grace Y. Sun."December 2009"Ph. D. University of Missouri-Columbia 2009.Alzheimer's disease (AD) is a progressive, fatal neurodegenerative disease marked with dementia. Secretory phospholipase A2-IIA (sPLA2-IIA) is an inflammatory protein known to have a role in the pathogenesis of multiple inflammatory diseases and is implicated in several neurodegenerative diseases. In AD, astrocytes become reactive and have increased expression of inflammatory cytokines such as IL-1[beta] and TNF-[alpha], and undergo increased oxidative stress. In these studies, we show that sPLA2-IIA mRNA is up-regulated in AD brains (compared to non-demented elderly brains). To further elucidate involvement of oxidative pathways in induction of sPLA2-IIA mRNA and protein by pro-inflammatory cytokines, we performed in vitro studies with immortalized astrocytes (DITNC) and various inhibitors and antioxidants. The results of these studies suggest the involvement of oxidative pathways, possibly the NADPH oxidase pathway. These results, taken together, identify sPLA2-IIA as an inflammatory factor for Alzheimer's disease, and support the involvement of NADPH oxidase in the cytokine induction of sPLA2-IIA in astrocytes and the possibility of using botanical antioxidants to ameliorate the inflammatory response in these cells.Includes bibliographical references

On simulation of local fluxes in molecular junctions

We present a pedagogical review of current density simulation in molecular junction models indicating its advantages and deficiencies in analysis of local junction transport characteristics. In particular, we argue that current density is a universal tool which provides more information than traditionally simulated bond currents, especially when discussing inelastic processes. However, current density simulations are sensitive to choice of basis and electronic structure method. We note that discussing local current conservation in junctions one has to account for source term caused by open character of the system and intra-molecular interactions. Our considerations are illustrated with numerical simulations of a benzenedithiol molecular junction.Comment: 10 pages, 6 figure

Geographical Analysis of US Green Sector Industry Concentration

This paper analyzes the geographic distribution of “green energy” sector clustering in the lower 48 United States using recent developments in industry concentration analysis. Evidence suggests that the ten green energy subsectors and the aggregate of the firms comprising the green energy sector are regionally concentrated. Positive changes in industry concentration from 2002 to 2006 tended to be greatest in non-metropolitan counties, suggesting comparative advantage with respect to site location for the composite of firms making up these sectors.Agglomeration, Location Quotient, Renewable Energy, Community/Rural/Urban Development, Industrial Organization, Research and Development/Tech Change/Emerging Technologies,

CRISPR/Cas9 advances engineering of microbial cell factories

One of the key drivers for successful metabolic engineering in microbes is the efficacy by which genomes can be edited. As such there are many methods to choose from when aiming to modify genomes, especially those of model organisms like yeast and bacteria. In recent years, clustered regularly interspaced palindromic repeats (CRISPR) and its associated proteins (Cas) have become the method of choice for precision genome engineering in many organisms due to their orthogonality, versatility and efficacy. Here we review the strategies adopted for implementation of RNA-guided CRISPR/Cas9 genome editing with special emphasis on their application for metabolic engineering of yeast and bacteria. Also, examples of how nuclease-deficient Cas9 has been applied for RNA-guided transcriptional regulation of target genes will be reviewed, as well as tools available for computer-aided design of guide-RNAs will be highlighted. Finally, this review will provide a perspective on the immediate challenges and opportunities foreseen by the use of CRISPR/Cas9 genome engineering and regulation in the context of metabolic engineering

Similar Levels of X-linked and Autosomal Nucleotide Variation in African and non-African populations of Drosophila melanogaster

<p>Abstract</p> <p>Background</p> <p>Levels of molecular diversity in Drosophila have repeatedly been shown to be higher in ancestral, African populations than in derived, non-African populations. This pattern holds for both coding and noncoding regions for a variety of molecular markers including single nucleotide polymorphisms and microsatellites. Comparisons of X-linked and autosomal diversity have yielded results largely dependent on population of origin.</p> <p>Results</p> <p>In an attempt to further elucidate patterns of sequence diversity in <it>Drosophila melanogaster</it>, we studied nucleotide variation at putatively nonfunctional X-linked and autosomal loci in sub-Saharan African and North American strains of <it>D. melanogaster</it>. We combine our experimental results with data from previous studies of molecular polymorphism in this species. We confirm that levels of diversity are consistently higher in African versus North American strains. The relative reduction of diversity for X-linked and autosomal loci in the derived, North American strains depends heavily on the studied loci. While the compiled dataset, comprised primarily of regions within or in close proximity to genes, shows a much more severe reduction of diversity on the X chromosome compared to autosomes in derived strains, the dataset consisting of intergenic loci located far from genes shows very similar reductions of diversities for X-linked and autosomal loci in derived strains. In addition, levels of diversity at X-linked and autosomal loci in the presumably ancestral African population are more similar than expected under an assumption of neutrality and equal numbers of breeding males and females.</p> <p>Conclusion</p> <p>We show that simple demographic scenarios under assumptions of neutral theory cannot explain all of the observed patterns of molecular diversity. We suggest that the simplest model is a population bottleneck that retains an ancestral female-biased sex ratio, coupled with higher rates of positive selection at X-linked loci in close proximity to genes specifically in derived, non-African populations.</p

Evaluering af forsøgsordning med elektriske løbehjul: Artikel

I juli 2018 og januar 2019 begyndte forsøgsordninger for speed pedelecs, elektriske løbehjul (el-løbehjul), elektriske skateboards og selvbalancerende køretøjer, hvor disse køretøjer er blevet lovlige at bruge på offentlige veje og stier. Den første evaluering af disse forsøgsordninger er gennemført fra september 2019 – januar 2020. Via Trafik har haft ansvar for de dele af evalueringen, som omhandler registeret og selvrapporteret adfærd, sikkerhed og holdninger. Denne artikel omhandler udelukkende el-løbehjul, og der fokuseres på den del af evalueringen, som Via Trafik har udarbejdet