Self-Assembly Mechanisms of Organosilanes and Porphyrins Investigated with Scanning Probe Microscopy

This dissertation details the development of new fabrication strategies for the preparation of spatially selective surfaces by combining techniques of particle lithography and scanning probe microscopy (SPM). This combination of lithography and nanoscale surface characterization was applied to study the mechanisms of molecular level surface-assembly of organosilanes and porphyrin on surfaces of Si(111). Particle lithography was used to investigate the surface assembly of 4-chloromethylphenyltrichlorosilane (CMPS) within exposed sites of nanoholes in selected solvents and at selected temperatures to gain insight into the details of self-polymerization. Nanopillars of CMPS were generated under selected conditions of solvent and temperature and characterized with atomic force microscopy (AFM). CMPS nanopillars were shown to grow taller with more layers at higher reactions temperatures. It was also observed that CMPS nanopillars grown in toluene formed more fractured pillars with multiple domains from a single nanoholes, compared to nanopillars grown in bicyclohexane that were observed to have more structured growth and less diverse morphology. The self-assembly of CMPS was strictly confined to nanoholes with the surrounding matrix showing very little evidence of non-specific adsorption. Surface platforms of nanopatterned CMPS nanopillars were fabricated within a resistive thin film of octadecyltrichlorosilane (OTS) to spatially direct and pattern the addition of 5,10,15,20-Tetra(4-pyridyl)porphyrin. The generation of CMPS-porphyrin heterostructures was studied ex-situ and confirmed by statistically significant changes in nanostructure height before and after the porphyrin addition. The fabrication of CMPS-porphyrin heterostructures from morphologically diverse CMPS nanopillar foundations was studied to provide insight into the mechanisms of CMPS nanopillar self-assembly. The morphology of final stage heterostructures closely resembled the original morphology of the CMPs nanopillars with little evidence of non-specific adsorption across the OTS thin film resist. Particle lithography was used to fabricate silicon porphyrin nanostructures on surfaces of Si(111) via a porphyrin-silane coupling reaction. Previous steps for nanopatterning porphyrin on a surface included an additional step to of an organosilane linker molecular that the porphyrin molecules could bind and assembly from. This new protocol coordinates a silane to each porphyrin macrocycle though a simple single vessel reaction system developed by Kurihara et al.1 Through this coupling reaction porphyrins can be directly assembled on surfaces of silicon and glass. Porphyrin nanostructures of nanoholes, nanorings and nanopillars as well as porphyrin thin films were generated using this technique

Factors Influencing Emergency Contraception Use in Indigent Populations

Introduction: Indigent women are disproportionately affected by unwanted, unplanned pregnancies. Studies previously identified lack of knowledge about emergency contraception (EC) as a major deterrent from use. This study was performed to address three potential barriers to the use of EC in indigent populations: culture and religion, patient education, and cost. For the entirety of this study, EC refers to levonorgestrel (LNG). Objectives: To determine the impact of culture and religion, patient education, and cost on EC use in the indigent population. Methods: This study was a cross-sectional observational study to explore and investigate relationships between indigent populations and the use of EC. To be included in the study, participants had to be: at least 14 years old, female, and have an annual household income below the federal poverty line (FPL). Those excluded were less than 14 years old, male, and reported an annual household income above the FPL. A questionnaire consisting of 31 survey questions were utilized to assess the endpoints of the study. The study utilized both paper and electronic forms of the survey. Participants signed informed consent to enable them participate in the study. Out of 319 participants, 59 met all inclusion criteria and were used in statistical analyses. Results:Based on Kruskal-Wallis results, religious groups’ acceptance of EC influenced indigent women’s decision to use it (p=0.016). Level of education also influenced women’s understanding of EC as an abortifacient and knowledge of when LNG is effective. Spearman rho revealed correlations between participants’ willingness to pay for EC or routine birth control and knowing that EC was an option (coefficient 0.391; p-value 0.005). There was also a correlation between the cost of EC and ultimate use (coefficient -0.603; p-value Conclusion: Our research found that religious groups’ acceptance of EC use and knowledge about how LNG works does affect the decision to use EC. Neither cultural identification nor cost of EC appears to have a significant impact on the final decision to use

B2 0902+34: A Collapsing Protogiant Elliptical Galaxy at z=3.4

We have used the visible integral-field replicable unit spectrograph prototype (VIRUS-P), a new integral field spectrograph, to study the spatially and spectrally resolved Lyman-alpha emission line structure in the radio galaxy B2 0902+34 at z=3.4. We observe a halo of Lyman-alpha emission with a velocity dispersion of 250 km/s extending to a radius of 50 kpc. A second feature is revealed in a spatially resolved region where the line profile shows blueshifted structure. This may be viewed as either HI absorption at -450 km/s or secondary emission at -900 km/s from the primary peak. Our new data, in combination with the 21 cm absorption, suggest two important and unexplained discrepancies. First, nowhere in the line profiles of the Lyman-alpha halo is the 21 cm absorber population evident. Second, the 21 cm absorption redshift is higher than the Lyman-alpha emission redshift. In an effort to explain these two traits, we have undertaken the first three dimensional Monte Carlo simulations of resonant scattering in radio galaxies. Though simple, the model produces the features in the Lyman-alpha data and predicts the 21 cm properties. To reach agreement between this model and the data, global infall of the HI is strictly necessary. The amount of gas necessary to match the model and data is surprisingly high, >= 10E12 solar masses, an order of magnitude larger than the stellar mass. The collapsing structure and large gas mass lead us to interpret B2 0902+34 as a protogiant elliptical galaxy.Comment: 30 pages, 8 figures, 4 tables, accepted in Ap

The Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) Collaborative Quality Improvement Initiative in Percutaneous Coronary Interventions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72388/1/j.1540-8183.2002.tb01071.x.pd

The canopy cover Webmap of the United Kingdom’s towns and cities

Urban trees and other green infrastructure are advocated as a cost-effective sustainable solution to ameliorate the socio-economic and environmental challenges of urbanisation. UK research has only recently started to quantify urban trees. Tree canopy cover percentage (TCC) is a useful indicator of tree presence. Its estimation can be reproducible, simple, fast, and cost-effective; it can also be evaluated through citizen science, improving people’s appreciation for urban trees and widening the data collection resource pool. This research summarises a citizen science assessment of the TCC of the UK’s 5,749 urban wards. Descriptive statistics are presented spanning local authority to country. The area-weighted mean (and standard error) of TCC across urban wards was 17.3 ± 0.1%. Nationally, the TCC were 11.8 ± 0.5%, 15.7 ± 0.5%, 17.5 ± 0.2%, and 18.1 ± 0.5%, for Northern Ireland, Scotland, England, and Wales, respectively. Results show that only 27.6% of urban wards had a TCC higher than 20%, previously suggested as a minimum target for UK towns. The findings highlight substantial geographical variance in TCC equity, as well as a negative correlation between TCC and deprivation. This information will be of value in urban forest strategy and management

Opportunities for organoids as new models of aging.

The biology of aging is challenging to study, particularly in humans. As a result, model organisms are used to approximate the physiological context of aging in humans. However, the best model organisms remain expensive and time-consuming to use. More importantly, they may not reflect directly on the process of aging in people. Human cell culture provides an alternative, but many functional signs of aging occur at the level of tissues rather than cells and are therefore not readily apparent in traditional cell culture models. Organoids have the potential to effectively balance between the strengths and weaknesses of traditional models of aging. They have sufficient complexity to capture relevant signs of aging at the molecular, cellular, and tissue levels, while presenting an experimentally tractable alternative to animal studies. Organoid systems have been developed to model many human tissues and diseases. Here we provide a perspective on the potential for organoids to serve as models for aging and describe how current organoid techniques could be applied to aging research

Hypomorphic PCNA mutation underlies a novel human DNA repair disorder

A number of human disorders, including Cockayne syndrome, UV-sensitive syndrome, xeroderma pigmentosum and trichothiodystrophy, result from the mutation of genes encoding molecules important for nucleotide excision repair. Here, we describe a novel syndrome in which the cardinal clinical features include postnatal growth retardation, hearing loss, premature aging, telangiectasia, neurological signs and photosensitivity, resulting from a homozygous missense (p.Ser228Ile) sequence alteration of the proliferating cell nuclear antigen (PCNA). PCNA is a highly conserved sliding clamp protein essential for DNA replication and repair. Due to this fundamental role, mutations in PCNA that profoundly impair protein function would be incompatible with life. Interestingly, while the p.Ser228Ile alteration appears to have no effect on protein levels or DNA replication, patient cells exhibit significant abnormalities in response to UV irradiation displaying substantial reductions in both UV survival and RNA synthesis recovery. The p.Ser228Ile change also profoundly alters PCNA’s interaction with Flap endonuclease 1 and DNA Ligase 1, DNA metabolism enzymes. Taken together our findings detail the first mutation of PCNA in humans, associated with a unique neurodegenerative disease displaying clinical and molecular features common to other DNA repair disorders, which we show to be attributable to a hypomorphic amino acid alteration

Carbon concentration declines with decay class in tropical forest woody debris

Carbon stored in woody debris is a key carbon pool in forest ecosystems. The most widely-used method to convert woody debris volume to carbon is by first multiplying field-measured volume with wood density to obtain necromass, and then assuming that a fixed proportion (often 50%) of the necromass is carbon. However, this crucial assumption is rarely tested directly, especially in the tropics. The aim of this study is to verify the field carbon concentration values of living trees and woody debris in two distinct tropical forests in Taiwan. Wood from living trees and woody debris across five decay classes was sampled to measure density and carbon concentrations. We found that both wood density and carbon concentration (carbon mass/total mass) declined significantly with the decay class of the wood. Mean (±SE) carbon concentration values for living trees were 44.6 ± 0.1%, while for decay classes one to five they were respectively 41.1 ± 1.4%, 41.4 ± 1.0%, 37.7 ± 1.3%, 30.5 ± 2.0%, and 19.6 ± 2.2%. Total necromass carbon stock was low, only 3.33 ± 0.55 Mg C ha−1 in the windward forest (Lanjenchi) and 4.65 ± 1.63 Mg C ha−1 in the lowland forest (Nanjenshan). Applying the conventional 50% necromass carbon fraction value would cause a substantial overestimate of the carbon stocks in woody debris of between 17% and 36%, or about 1 Mg of carbon per hectare. The decline in carbon concentration and the increase of variances in the heavily decayed class suggest that in high-diversity tropical forests there are diverse decomposition trajectories and that assuming a fixed carbon fraction across woody pieces is not justified. Our work reveals the need to consider site-specific and decay class-specific carbon concentrations in order to accurately estimate carbon stocks and fluxes in forest ecosystems. If the marked decline in carbon content with necromass decay is typical of tropical forests, the dead wood carbon pool in the biome needs revision and is likely to be overestimate

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes