Browsing by Author "Ho, Tung"

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    Drug Discovery Through Drug Perturbation Pathway Modeling and Network Analysis
    (Office of the Vice Chancellor for Research, 2014-04-11) Ho, Tung; Hakola, Krista; Wagle, Pragat; Rouse, Evan; Shadmand, Mehdi; Han, Juyeon; Ibrahim, Sara
    Due to intrinsic complex molecular interactions, the “one disease – one target – one drug” strategy for disease treatment is no longer the best option to treat cancers. To assess drug pharmacological effects, we assume that “ideal” drugs for a patient can treat or prevent the disease by modulating gene expression profiles of this patient to the similar level with those in healthy people. A new approach for drug-protein interactions curation, drug-drug similarity network comparison, and integrative pathway model construction and evaluation was introduced to determine optimal drugs for various cancers. Drug-protein interaction curation is conducted to discover novel drug-protein relationships and is categorized as: up regulated, down regulated, indirect up or down, ambiguous and unknown. The manual curation can be utilized for drug repurposing and examining drug mechanism on a pathway level. A drug-drug similarity network model is built by examining similar targets, therapeutic mechanisms, side effects, and chemical structures. Drug similarity analysis is useful for drug repositioning because similar drugs may have compatible therapeutic or toxic effects for a disease. Drug similarity networks are constructed and examined through a molecular network visualization platform. An integrative disease-specific pathway model is also built to gain a more holistic view of disease mechanisms by including every significant disease-specific protein. Including drugs on the pathway through target information can also offer a clear mechanism for the drug’s action. We also transform integrated pathways into network models and ranked drugs based on the network topological features of drug targets, drug-affecting genes/proteins, and curated disease-specific proteins. Combining our three approaches could potentially lead to advances in drug repurposing and repositioning.
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    Layer-By-Layer Self-Assembly of CIGS Nanoparticles and Polymers for All-Solution Processable Low-Cost, High-Efficiency Solar Cells
    (Office of the Vice Chancellor for Research, 2013-04-05) Ho, Tung; Vittoe, Robert; Kakumanu, Namratha; Shrestha, Sudhir; Agarwal, Mangilal; Varahramyan, Kody
    Thin film solar cells made from copper indium gallium selenide (CIGS) materials have shown great potentials of providing low cost, high efficiency panels viable for wide spread commercial usage. Layer-by-layer (LbL) self-assembly is a low-cost, versatile nanofilm deposition process, however introduces polymers in the nanoparticles films, which reduces charge transport thereby affecting solar cell efficiency. This research aims to study various polymer materials to replace currently used insulating polymers in LbL, such as poly(sodium-4-styrenesulfonate) (PSS) and polyethyenimine (PEI). This poster will present processes and results of CIGS nanoparticles synthesis using controlled heating of CuCl, InCl3, GaCl3, and Se in oleyamine; functionalization of the particles to disperse in organic and aqueous-based solvents for LbL; and initial outcomes of CIGS, polymers LbL film fabrication and characterization. The size distribution of synthesized nanoparticles cleaned through alternate suspension and precipitation in chloroform and ethanol shows a peak at 72 nm. Particles light absorption properties measured with ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy shows good spectrum coverage with band edge near 1100 nm. The X-ray diffraction (XRD) results of the particles confirms the composition and tetragonal chalcopyrite crystal structure of CIGS materials. Chemical-bath-deposition of cadmium sulfide (CdS) and spray-coating of zinc oxide (ZnO) films are used along with LbL absorbing film in realization of a solar cell device. The fabricated devices are tested using semiconductor characterization instrument.