Elimination of Acoustical Noise for STM Examination of Pentacene Crystallization on Si (001)

Organic electronics are used in traditional solar cells and also in flexible electronics. Unfortunately, the conductivities of organic semiconductors are significantly lower than their inorganic counterparts. This project examines crystallization by directed selfassembly of the organic molecules via a surface reconstruction as a method to increase conductivity. The crystallization is characterized by Scanning Tunneling Microscopy (STM). In order to achieve optimal STM images, this work examined: (1) noise isolation, (2) etching sharp STM tips and (3) achieving reconstructed Si surface. The STM is housed in a glovebox to keep the surface reconstructions and organic molecules from degrading. However, acoustical noise of the glovebox circulation pump makes achieving atomic resolution impossible. Introducing a foam-lined acoustical shell around the microscope significantly reduced acoustic noise and atomic resolution is achieved. We also determined optimal PtIr tip etching procedures, demonstrating that an alternating current of 40 V in a 1M CaCl2 solution results in a tip with an ~ 13μm radius of curvature, comparable to other PtIr tips found in literature. Finally, we demonstrated a Si(001) surface with 20nm terrace widths and two atomic height steps achieved by cleaving inside the N2 environment.https://engagedscholarship.csuohio.edu/u_poster_2016/1024/thumbnail.jp

Elimination of Acoustical Noise for STM Examination of Pentacene Crystallization on Si (001)

Organic electronics are used in traditional solar cells and also in flexible electronics. Unfortunately, the conductivities of organic semiconductors are significantly lower than their inorganic counterparts. This project examines crystallization by directed selfassembly of the organic molecules via a surface reconstruction as a method to increase conductivity. The crystallization is characterized by Scanning Tunneling Microscopy (STM). In order to achieve optimal STM images, this work examined: (1) noise isolation, (2) etching sharp STM tips and (3) achieving reconstructed Si surface. The STM is housed in a glovebox to keep the surface reconstructions and organic molecules from degrading. However, acoustical noise of the glovebox circulation pump makes achieving atomic resolution impossible. Introducing a foam-lined acoustical shell around the microscope significantly reduced acoustic noise and atomic resolution is achieved. We also determined optimal PtIr tip etching procedures, demonstrating that an alternating current of 40 V in a 1M CaCl2 solution results in a tip with an ~ 13μm radius of curvature, comparable to other PtIr tips found in literature. Finally, we demonstrated a Si(001) surface with 20nm terrace widths and two atomic height steps achieved by cleaving inside the N2 environment.https://engagedscholarship.csuohio.edu/u_poster_2016/1024/thumbnail.jp

Elimination of Acoustic noise in STM Analysis of Polymer Crystallization on Au (111)

Organic molecules offer a potentially cheap and environmentally friendly alternative to traditional silicon based electronics. The main limitation is that they are not as conductive as their inorganic counter parts. By crystalizing organic molecules, it is possible to increase the conductivity so that they can be more competitive with silicon electronics. This project examines the crystallization of polymers through selfassembly on the Au(111) surface reconstruction. The success of the crystallization is characterized with scanning tunneling microscopy (STM). In order to achieve high resolution STM images, we examined acoustic isolation by enclosing the microscope within a rubber-coated box, which was not effective, and a cylindrical shell lined with open cell foam. This was determined by examining both the images and the tunneling current data both with and without the acoustic isolation. We were further able to demonstrate that acoustic noise, while it destroys the ability to take high resolution images, does not appear in the tunneling current, which has not been previously reported. Finally, we report on the ability to create flat terraces of the Au(111) surface.https://engagedscholarship.csuohio.edu/u_poster_2016/1025/thumbnail.jp

SB-224289 Antagonizes the Antifungal Mechanism of the Marine Depsipeptide Papuamide A

In order to expand the repertoire of antifungal compounds a novel, high-throughput phenotypic drug screen targeting fungal phosphatidylserine (PS) synthase (Cho1p) was developed based on antagonism of the toxin papuamide A (Pap-A). Pap-A is a cyclic depsipeptide that binds to PS in the membrane of wild-type Candida albicans, and permeabilizes its plasma membrane, ultimately causing cell death. Organisms with a homozygous deletion of the CHO1 gene (cho1ΔΔ) do not produce PS and are able to survive in the presence of Pap-A. Using this phenotype (i.e. resistance to Pap-A) as an indicator of Cho1p inhibition, we screened over 5,600 small molecules for Pap-A resistance and identified SB-224289 as a positive hit. SB-224289, previously reported as a selective human 5-HT1B receptor antagonist, also confers resistance to the similar toxin theopapuamide (TPap-A), but not to other cytotoxic depsipeptides tested. Structurally similar molecules and truncated variants of SB-224289 do not confer resistance to Pap-A, suggesting that the toxin-blocking ability of SB-224289 is very specific. Further biochemical characterization revealed that SB-224289 does not inhibit Cho1p, indicating that Pap-A resistance is conferred by another undetermined mechanism. Although the mode of resistance is unclear, interaction between SB-224289 and Pap-A or TPap-A suggests this screening assay could be adapted for discovering other compounds which could antagonize the effects of other environmentally- or medically-relevant depsipeptide toxins

Evaluating complementary and alternative medicine interventions: in search of appropriate patient-centered outcome measures

BACKGROUND: Central to the development of a sound evidence base for Complementary and Alternative Medicine (CAM) interventions is the need for valid, reliable and relevant outcome measures to assess whether the interventions work. We assessed the specific needs for a database that would cover a wide range of outcomes measures for CAM research and considered a framework for such a database. METHODS: The study was a survey of CAM researchers, practitioners and students. An online questionnaire was emailed to the members of the Canadian Interdisciplinary Network for CAM Research (IN-CAM) and the CAM Education and Research Network of Alberta (CAMera). The majority of survey questions were open-ended and asked about outcome measures currently used, outcome measures' assessment criteria, sources of information, perceived barriers to finding outcome measures and outcome domains of importance. Descriptive quantitative analysis and qualitative content analysis were used. RESULTS: One hundred and sixty-four completed surveys were received. Of these, 62 respondents reported using outcome measures in their CAM research and identified 92 different specific outcomes. The most important barriers were the fact that, for many health concepts, outcome measures do not yet exist, as well as issues related to accessibility of instruments. Important outcome domains identified included physical, psychological, social, spiritual, quality of life and holistic measures. Participants also mentioned the importance of individualized measures that assess unique patient-centered outcomes for each research participant, and measures to assess the context of healing and the process of healing. CONCLUSION: We have developed a preliminary framework that includes all components of health-related outcomes. The framework provides a foundation for a larger, comprehensive collection of CAM outcomes. It fits very well in a whole systems perspective, which requires an expanded set of outcome measures, such as individualized and holistic measures, with attention to issues of process and context