A Program For Surface Classification

This thesis presents the classification theorem of compact connected surfaces, its proof, and a computer implementation. The theorem, first stated by Mobius in 1861 and more formally by Jordan in 1866, states that every compact, connected surface is homeomorphic to either a 2-sphere, a connected sum of tori, or a connected sum of projective planes. The proof we present consists of an algorithm to take a polygon representation to normal form. A polygon representation of a surface is essentially the result of cutting the surface up until it lies flat, where we identify the cut edges such that we could paste it back together again. A polygon representation in normal form has distinguishable tori or projective plane components and can be easily classified from this state. The computer implementation is written in JavaScript and includes a graphical interface that allows the user to progress through the algorithm by cut and paste operations. The program is intended as a learning tool for students in introductory topology courses

Effects Associated with the Deployment of Autonomous and Connected Vehicles: Insights from Las Vegas, NV

Autonomous and connected vehicles (ACVs) are quickly evolving and becoming part of our transportation systems. Adoption of this technology is largely dependent on public perceptions and comfort. The objective of this study was to evaluate public perceptions of ACVs and gain knowledge regarding potential use and important aspects towards acceptance of ACVs. Specifically, the differences in perceptions of people who have ridden an ACV are compared to those who have not. A stated preference approach was utilized, as this is an emerging technology. Two different survey questionnaires were distributed. The first survey was distributed to participants considered to be members of the general public. The second survey was distributed to participants who had ridden an autonomous and connected shuttle bus operating in downtown Las Vegas. Data were analyzed using penalized logistic regression. Results suggest that people from the general public who have had exposure to or have ridden an ACV feel more positively about them becoming more widespread. From the shuttle-rider survey, participants expressed positive sentiments with a higher portion than those from the general survey. This may suggest that a public exposure period to ACVs would benefit those interested in implementing ACVs. Younger people, middle to low income households and males also felt more positively about ACVs than their older, high income and female counterparts, respectively. However, from the shuttle-rider survey, lower income people favored ACVs more than higher income people. In addition, commuting distances and amount of vehicle travel may increase. This could potentially result in sprawling which certainly has public health and planning implications

Assessing asthma in adult clinical trials of inhaled B2-agonists: a search for a standard primary outcome measure

PhDSince the late 1960s the safety of inhaled B2-agonists has been questioned and the longtenn regular use of these drugs has been linked to increasing morbidity and mortality. National and international guidelines recommend that short acting inhaled B2-agonists should only be used on an "as needed" basis and yet the evidence for these recommendations is still unclear, one reason being the lack of common definition for an outcome. The Regular Use of Salbutamol Trial (TRUST) was designed to assess the risks and benefits of regular versus as needed salbutamol in mild to moderate asthma. In order to establish whether a common primary outcome measure could improve the comparability and interpretation of different trials, a systematic rcyiew of randomised controlled trials of long and short acting inhaled B2-agonists in asthmatic subjects was undertaken to identify well designed trials in this field and primary outcome measures used. The systematic review identified five different primary outcome measures from 26 trials of long and short acting inhaled B2-agonists. The TRUST definition of exacerbation was compared with the five primary outcome measures identified using the TRUST diary card data. In addition, the diary card variables (changes in PEF, symptom scores and medication use) were examined to determine the extent to which they predicted exacerbations according to the different definitions. The use of additional corticosteroids and an increase in daytime symptoms of two or more above baseline were the strongest predictors of all four definitions of exacerbation. A fall in morning PEF of 100 lImin was strongly associated with all definitions of exacerbation but was not a sensitive measure. In conclusion, exacerbations of asthma could be identified by use of additional corticosteroids and an increase in two or more of daytime symptoms. The specificity could be improved by including morning PEF but this may reduce patient compliance with study protocol in asthma trials

Engineering Soft Tissue Replacements and the Development of Novel Technologies to Heal these Wounds

The primary focus of tissue engineering is to develop biological substitutes capable of restoring, maintaining, or improving native tissue function. This field advances an exciting array of solutions for organ repair and wound healing. In the United States alone over 6.5 million people are affected by chronic wounds every year, which account for over $25 billion of healthcare expenses. Vascularization and fast anastomosis with the host are essential in engineering cellular constructs that survive once implanted. In the last decade, there has been extensive investigation into fabrication techniques to create tissue replacements that are rapidly perfused post-implantation to address this issue. Three-dimensional bioprinting is a methodology used for generating 3D constructs of various sizes and shapes from a digital model using a layer-by-layer approach. These digital models can be derived from patient images, such as CT and MRI scans, to produce patient-specific tissue replacements. The fabrication of biomimetic constructs plays an essential role in the advancement of tissue engineering, and provides the ability to form 3D constructs that are able to recapitulate the in vivo structure and function of complex tissues. The Palmetto Printer, developed at the Medical University of South Carolina, is a custom-built multi-dispenser system that uses programmable robotic manufacturing methods to generate 3D heterogeneous tissue constructs. The assessment of the Palmetto bioprinter showed high cell viability (\u3e95%) and significant cell proliferation within the printed constructs over 8 days. Therefore, this technique proves its ability to generate scaffolds that allow cell growth, communication, and the formation of networks; each a requirement of vascularization. Scaffold-free tissue engineering aims to produce physiologically-relevant 3D multicellular constructs through the process of cellular self-assembly. We have developed a scaffold-free prevascular implant model with dense endothelial networks surrounded by extracellular matrix, similar to capillary vasculature. Upon implantation, we found that the host rapidly endothelialized these constructs (\u3c6hr), and were perfused by 72 hours post-implantation. We have demonstrated that this technology can be modified by growth factors and can be scaled up into larger, more complex geometries. Furthermore, bioprinter fabrication could allow the creation of personalized implants. As an application for these fabrication techniques, we developed a novel wound dressing for the treatment of chronic wounds. The Smart Wound Dressing is a multi-component device made up of three separate layers that individually address different facets of the chronic wound environment. This combinatorial approach will provide an exciting new option for the treatment of these non-healing wounds

Nuptial gift chemistry reveals convergent evolution correlated with antagonism in mating systems of harvestmen (Arachnida, Opiliones)

Nuptial gifts are material donations given from male to female before or during copulation and are subject to sexual selection in a wide variety of taxa. The harvestman genus Leiobunum has emerged as a model system for understanding the evolution of reproductive morphology and behavior, as transitions between solicitous and antagonistic modes of courtship have occurred multiple times within the lineage and are correlated with convergence in genital morphology. We analyzed the free amino acid content of nuptial gift secretions from five species of Leiobunum using gas chromatography–mass spectrometry. Multivariate analysis of the free amino acid profiles revealed that, rather than clustering based on phylogenetic relationships, nuptial gift chemical composition was better predicted by genital morphology and behavior, suggesting that convergent evolution has acted on the chemical composition of the nuptial gift. In addition, we found that, species with solicitous courtship produce gifts consisting of a 19% larger proportion of essential amino acids as compared to those with more antagonistic courtship interactions. This work represents the first comparative study of nuptial gift chemistry within a phylogenetic framework in any animal group and as such contributes to our understanding of the evolution of reproductive diversity and the participant role of nuptial gift chemistry in mating system transitions

Two Amino Acid Residues Contribute to a Cation-π Binding Interaction in the Binding Site of an Insect GABA Receptor

Cys-loop receptor binding sites characteristically possess an "aromatic box," where several aromatic amino acid residues surround the bound ligand. A cation-π interaction between one of these residues and the natural agonist is common, although the residue type and location are not conserved. Even in the closely related vertebrate GABA_A and GABA_C receptors, residues in distinct locations perform this role: in GABA_A receptors, a Tyr residue in loop A forms a cation-π interaction with GABA, while in GABA_C receptors it is a loop B residue. GABA-activated Cys-loop receptors also exist in invertebrates, where they have distinct pharmacologies and are the target of a range of pesticides. Here we examine the location of GABA in an insect binding site by incorporating a series of fluorinated Phe derivatives into the receptor binding pocket using unnatural amino acid mutagenesis, and evaluating the resulting receptors when expressed in Xenopus oocytes. A homology model suggests that two aromatic residues (in loops B and C) are positioned such that they could contribute to a cation-π interaction with the primary ammonium of GABA, and the data reveal a clear correlation between the GABA EC_(50) and the cation-π binding ability both at Phe206 (loop B) and Tyr254 (loop C), demonstrating for the first time the contribution of two aromatic residues to a cation-π interaction in a Cys-loop receptor

Key emerging issues in frontotemporal dementia.

Frontotemporal dementia (FTD) encompasses the syndromes of behavioural variant FTD (bvFTD) and primary progressive aphasia (PPA) and refers to those neurodegenerative diseases characterised by predominant pathological involvement of the frontal and temporal lobes. Recent years have witnessed major advances in the clinical characterisation of FTD, reflected in the publication of updated diagnostic criteria for bvFTD and PPA, and the discovery of new pathogenic mutations has added to the understanding of genotype-phenotype interactions and of disease mechanisms. Emerging results from longitudinal studies of familial FTD show that imaging and cognitive changes occur years before symptom onset and such studies may yield biomarkers of early disease that in turn will facilitate earlier diagnosis. The hope and (guarded) expectation is that these advances may together herald the beginning of the end of the chapter in which FTD is considered an inexorably progressive and untreatable condition.Dr Chan is funded by the Cambridge NIHR Biomedical Research Centre and receives grant income from the UK Medical Research Council, Technology Strategy Board and the Cambridge Isaac Newton Trust.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00415-015-7880-