archives@tulane.edu / Fibrotic diseases comprise up to 45% of deaths in the industrialized world. Few effective anti-fibrotic therapeutics exist, due in part to the lack of human-relevant preclinical models. The goal of this research was to improve the modeling of fibrotic diseases in microphysiological systems (MPS) by engineering quiescence in cultured human fibroblasts prior to MPS incorporation. To create an assay for testing this approach, a versatile organ chip was designed while optimizing workflow for production of the organ chip molds with an SLA 3D printer. After identifying 2D culture conditions that repress fibroblast activation, we tested the hypothesis that the 2D culture protocol would impact the fibrotic baseline in our MPS. 3D confocal microscopy and multi-metric image analysis of immunostaining for cellular and extracellular matrix (ECM) components via intensity and pattern quantification revealed the establishment of more physiological baseline for MPS fibrosis models. To test in a disease-relevant context, we created a model of the stromal reaction in lung cancer using our organ chip and demonstrated that our integrated MPS can be used to quantify the fibrosis-inducing effects of cancer cells that drive stromal reactions. / 1 / Max Wendell

The feasibility of locating the major household appliance industry in Utah was studied by comparing a Utah location with present production sites for this commodity. Major elements of cost were projected in detail according to a hypothetically constructed model. The Utah location showed advantages in transportation and labor costs while at the same time having a disadvantage in the cost of steel. Since the analysis is made with respect to the model, which is based on certain assumptions, the use of different models would naturally lead to different results. Both the advantages and disadvantages of the Utah location would most likely change in the event that a facility for the construction of household appliances were established in Utah. The advantages of the Utah site would become more defined .

The fabrication of new and novel materials contributes to qualitative enhancement of human life. Among the various branches of fabrication, nanolithography is an emerging neoteric fabrication technology. Even though nanofabrication procedures and the techniques can be precisely controlled through various error prevention techniques and algorithms, there is always a probability of human or instrumental error in a fabrication process. Minimization or rectification of errors during the fabrication process would increase the productivity and reduce cost per unit of the fabricated devices. Therefore there is a compelling need for an error rectification system. Compared to the number of techniques available for fabrication using nanolithography, the techniques available for error rectification are very limited. Successful implementation of more error rectification techniques may have a huge impact in device fabrication and manufacturing processes. The main focus our work is the development of a lithographic error rectification system that we named as Polymeric Submicron Editor (POSE). This system is made of submicron "pens" and "erasers" made from flexible polymers. The pens and erasers were made of polydiemethylsiloxane (PDMS) and agarose hydrogel respectively. They are fabricated by template synthesis from anisotropically track etched conical micropores in glass. The polymeric pens mounted to piezoelectric motors were used to deposit and remove submicron patterns driven by diffusion. This entire deposition system is housed on an inverted microscope to optically track and register the area of deposition so that if required it can be erased and rectified by agarose hydrogel erasers and PDMS pens. POSE can deposit, erase and rectify patterns with submicron resolution. Apart from the development of POSE, this process also led to the development of techniques for, (i) two dimensional gradient etching in tracked glass, (ii) mask less photolithography and with tracks etched glass and (iii) polymeric microfabrication which will also be covered in detail in this dissertation

Nanofluidic devices are structures having at least one dimension in the submicron range, which is of the same order of magnitude as the sizes of biomolecules and bioparticles such as proteins and viruses. As a result, size-selective separations are important applications for nanofluidics. Well-defined micro or nano device structures fabricated via micromachining have greatly reduced sample consumption and enabled separations in a parallel fashion, promising significant speed and resolution advantages over conventional size separation techniques, such as gel electrophoresis and size exclusion chromatography. In collaboration with others, I have developed a size separation method using nanofluidic devices consisting of an array of parallel planar nanochannels with varying heights. Separation of nanoparticles is accomplished by simply flowing a liquid suspension of the particles through the nanochannels via capillary action. When a mixture of particles arrives at an interface, where the channel steps from a deeper to a shallower segment, larger particles become trapped and smaller particles pass through, thereby achieving separation. In this dissertation, I demonstrated the successful trapping of polymer nanobeads and two types of virus capsids (30 nm hepatitis B virus capsids and 120 nm herpes simplex virus type 1 capsids) using nanochannels with two different channel height segments. Furthermore, I studied the fractionation of nanoparticles in nanochannels with three different channel height segments. The effects of surfactants and an alternating current electric field on particle distribution were investigated, both of which aided in the prevention of channel clogging. Most recently, I applied the nanosieving method for separating lipoproteins, which are important in the diagnosis of cardiovascular disease. Promising results were obtained, indicating that the major lipoprotein classes, including intermediate density lipoproteins (IDL, 23-35 nm), low-density-lipoproteins (LDL, 18-25 nm) and high-density-lipoproteins (HDL, 5-12 nm), may eventually be fractionated using three-segment nanochannels. To successfully fractionate lipoprotein mixtures, characterization of flow dynamics in three-segment nanochannels, passivation of the surface to prevent nonspecific protein adsorption, application of an electric field to help particles overcome an energy barrier, and use of multi-color fluorescent labeling to assist detection are required. I studied the channel passivation performance of polyethylene glycol (PEG) and used dual-color fluorescence detection for the separation of a binary protein mixture. Finally, I fabricated channels with monotonically changing barrier heights and demonstrated differential trapping of polymer beads. The data trend followed a slit model derived from a model developed by Giddings for size exclusion chromatography.

Yes / Concrete with smart and functional properties (e.g., self-sensing, self-healing, and energy-harvesting) represents a transformative direction in the field of construction materials. Energy-harvesting concrete has the capability to store or convert the ambient energy (e.g., light, thermal, and mechanical energy) for feasible uses, alleviating global energy and pollution problems as well as reducing carbon footprint. The employment of energy-harvesting concrete can endow infrastructures (e.g., buildings, railways, and highways) with energy self-sufficiency, effectively promoting sustainable infrastructure development. This paper provides a systematic overview on the principles, fabrication, properties, and applications of energy-harvesting concrete (including light-emitting, thermal-storing, thermoelectric, pyroelectric, and piezoelectric concretes). The paper concludes with an outline of some future challenges and opportunities in the application of energy-harvesting concrete in sustainable infrastructures.

Chlorine is used as a powerful disinfectant in water-related industries and in the food industry to remove bacteria and other harmful contaminants. We present a solution-based fabrication process for a biodegradable electrochemical free chlorine sensor using asparagine that is functionalized onto graphene oxide (GO). An ink solution of the GO functionalized with asparagine was fabricated then deposited onto a screen-printed carbon electrode (SPCE) using a spin-coater. The sensor showed high a sensitivity of 0.30 μA ppm−1 over a linear range of 0 to 8 ppm with a hysteresis-limited resolution of 0.2 ppm, very high selectivity in the presence of commonly interfering ions, and an operating voltage well below the reduction potential of dissolved oxygen. The sensor response time to achieve a steady state was 50 s, and it showed little change in its drift response over 16 h and over a temperature range of 10 to 45 °C. From the development of the free chlorine sensor, over 9000 datapoints were collected and used for training a neural network model to quantify and characterize factors affecting the free chlorine sensor performance. A readout system was designed with a printed circuit board and an android app to simplify free chlorine sensing for an end user. / Thesis / Master of Applied Science (MASc) / Free chlorine is used to disinfectant sources of water, and eliminate pathogens. The World Health Organization (WHO) maintains strict amounts of free chlorine in water due to its widespread usage owed to its low cost and persistence in water systems. Too little, and it will not be an effective disinfectant, and too much and the high consumption of free chlorine increases the risk cancer or the formation of hazardous chemicals. Recently, free chlorine sensors that measure an electrical response proportional to the amount of free chlorine are gaining interest for fast, accurate, and repeatable measurements. This thesis focuses on the design, fabrication, and evaluation of these sensors made using biodegradable materials in a solution-based fabrication processes with the aim of working towards large-scale fabrication of a printable ink. First, we review the results achieved by the sensors within recent literature. Second, we present the design of a sensor that aims to achieve environmentally friendly goals and maintain competitive performance characteristics. The, the sensor is tested under various conditions with its performance quantified under different conditions. Third, the sensor is characterized using a neural network to measure its performance and identify sources of improvement for future designs. Finally, we incorporate the sensor with an android app to measure free chlorine in remote water systems.

Part A of two parts. Part B titled: "The Processing and Evaluation of Long Lived GaA1As Channeled Substrate Planar Lasers". / <p> The design and fabrication of a low cost optical communications link is described. The evaluation of this system shows that it can transmit bipolar analog signals in a bandwidth of O to 17 kHz with less than 0.1% non-linearity, Combined with an autoranging capability, the linear link is demonstrated to be useful for high accuracy remote data acquisiton. </p> / Thesis / Master of Engineering (MEngr)

<P> In this thesis, several methods of material integration into organic photovoltaic devices are investigated by fabricating solution processed and vacuum coated devices. Each of these methods is aimed at examining and improving one or more of the four critical factors that determine solar cell efficiency: (1) photovoltage, (2) light absorption, (3) exciton separation, and ( 4) charge collection. To investigate and improve photovoltage, the photovoltaic properties of different M-Phthalocyanine/Fullerene (M-Pc/C60 ) blends are measured and demonstrate an improved open circuit voltage (Voc) using trivalent-metal phthalocyanine. Rubrene is also added to the tl-Pc/C60 cells and shown to systematically increase the Voc. To improve light absorption, two new device structures are developed: the parallel tandem cell and the heteromorphic cell. The parallel tandem cell is demonstrated using both all-vacuum coated materials as well as a combination of vacuum and solution processed materials. Results show definitive and significant current contribution from the near-infrared (NIR) wavelengths, and concomitant increase in photocurrent and power conversion efficiency (PCE). The heteromorphic cell demonstrates the integration of two polymorphs of the same M-Pc, yielding a broader external quantum efficiency (EQE) spectrum in the IR region and an increase in the overall PCE. To investigate exciton separation and charge collection, time of flight photoconductivity studies are performed on varying compositions of solution processed polymer/fullerene films as well as pristine and blended M-Pc:C60 films. Results verify the necessity for balanced carrier transport in blended systems, and t he importance of carrier mobility for achieving high fill factors. Finally, the stability of a relatively new polythiophene (PQT-12) in an organic solar cell is investigated , and shown to significantly increase the device lifetime as compared to the standard P3HT polymer. </p> / Thesis / Doctor of Philosophy (PhD)

Photoresist is a light sensitive material whose physical and chemical properties change when exposed to light. Photoresist makes it possible to transfer the image of a circuit pattern directly onto a substrate. The first part of this work deals with developing a photo process using AZ 1518 and AZ P4330 positive resists on SiC substrate. The aim was to determine the optimal spin parameters, softbake time, and exposure time for these resists matching their thickness. AZ 1518 process was developed for a 1.76 um thickness and AZ P4330 for 4.3 um thickness. With the parameters obtained the resist had about 5% of difference in thickness across a wafer surface. The absence of practical wet chemical etching of SiC is the reason for the study of dry, plasma etching of SiC in this thesis. There is an interest in photoresist as an etch mask because it is cheap, easy to deposit, pattern and remove. However its ability to mask etching of materials with high bond strength like SiC is limited. This work examines its selectivity under various etching parameters and determines the effect of increase in the RF power on selectivity, SiC etch rate and photoresist etch rate.

No description available.