Matching Items (17)
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- Genre: Masters Thesis
Description
A wireless hybrid device for detecting volatile organic compounds (VOCs) has been developed. The device combines a highly selective and sensitive tuning-fork based detector with a pre-concentrator and a separation column. The selectivity and sensitivity of the tuning-fork based detector is optimized for discrimination and quantification of benzene, toluene, ethylbenzene, and xylenes (BTEX) via a homemade molecular imprinted polymer, and a specific detection and control circuit. The device is a wireless, portable, battery-powered, and cell-phone operated device. The device has been calibrated and validated in the laboratory and using selected ion flow tube mass spectrometry (SFIT-MS). The capability and robustness are also demonstrated in some field tests. It provides rapid and reliable detection of BTEX in real samples, including challenging high concentrations of interferents, and it is suitable for occupational, environmental health and epidemiological applications.
ContributorsChen, Zheng (Author) / Tao, Nongjian (Thesis advisor) / Chae, Junseok (Committee member) / Forzani, Erica (Committee member) / Arizona State University (Publisher)
Created2011
Description
An imaging measurement technique is developed using surface plasmon resonance. Plasmonic-based electrochemical current imaging (P-ECi) method has been developed to image the local electrochemical current optically, it allows us to measure the current density quickly and non-invasively [1, 2]. In this thesis, we solve the problems when we extand the P-ECi technique to the field of thin film system. The P-ECi signal in thin film structure was found to be directly proportional to the electrochemical current. The upper-limit of thin film thickness to use the proportional relationship between P-ECi signal and EC current was discussed by experiment and simulation. Furthermore, a new algorithm which can calculate the current density from P-ECi signal without any thickness limitation is developed and tested. Besides, surface plasmon resonance is useful phenomenon which can be used to detect the changes in the refractive index near the gold sensing surface. With the assistance of pH indicator, by applied EC potential on the gold film as the working electrode, the detection of H2 evolution reaction can be enhanced. This measurement technique is useful in analyzing local EC information and H2 evolution. References [1] S. Wang, et al., "Electrochemical Surface Plasmon Resonance: Basic Formalism and Experimental Validation," Analytical Chemistry, vol. 82, pp. 935-941, 2010/02/01 2010. [2] X. Shan, et al., "Imaging Local Electrochemical Current via Surface Plasmon Resonance," Science, vol. 327, pp. 1363-1366, March 12, 2010 2010.
ContributorsZhao, Yanjun (Author) / Tao, Nongjian (Thesis advisor) / Wang, Shaopeng (Committee member) / Tsow, Tsing (Committee member) / Arizona State University (Publisher)
Created2013
Description
This work demonstrates the integration of a wearable particulate detector and a wireless chemical sensor into a single portable system. The detection philosophy of the chemical sensor is based on highly selective and sensitive microfabricated quartz tuning fork arrays and the particle detector detects the particulate level in real-time using a nephelometric (light scattering) approach. The device integration is realized by carefully evaluating the needs of flow rate, power and data collection. Validation test has been carried out in both laboratory and in field trials such as parking structures and highway exits with high and low traffic emissions. The integrated single portable detection system is capable of reducing the burden for a child to carry multiple devices, simplifying the task of researchers to synchronize and analyze data from different sensors, and minimizing the overall weight, size, and cost of the sensor. It also has a cell phone for data analysis, storage, and transmission as a user-friendly interface. As the chemical and particulate levels present important exposure risks that are of high interests to epidemiologists, the integrated device will provide an easier, wearable and cost effective way to monitor it.
ContributorsGao, Tianle (Author) / Tao, Nongjian (Thesis advisor) / Chae, Junseok (Committee member) / Tsow, Tsing (Committee member) / Arizona State University (Publisher)
Created2012
Description
Advances in miniaturized sensors and wireless technologies have enabled mobile health systems for efficient healthcare. A mobile health system assists the physician to monitor the patient's progress remotely and provide quick feedbacks and suggestions in case of emergencies, which reduces the cost of healthcare without the expense of hospitalization. This work involves development of an innovative mobile health system with adaptive biofeedback mechanism and demonstrates the importance of biofeedback in accurate measurements of physiological parameters to facilitate the diagnosis in mobile health systems. Resting Metabolic Rate (RMR) assessment, a key aspect in the treatment of diet related health problems is considered as a model to demonstrate the importance of adaptive biofeedback in mobile health. A breathing biofeedback mechanism has been implemented with digital signal processing techniques for real-time visual and musical guidance to accurately measure the RMR. The effects of adaptive biofeedback with musical and visual guidance were assessed on 22 healthy subjects (12 men, 10 women). Eight RMR measurements were taken for each subject on different days under same conditions. It was observed the subjects unconsciously followed breathing biofeedback, yielding consistent and accurate measurements for the diagnosis. The coefficient of variation of the measured metabolic parameters decreased significantly (p < 0.05) for 20 subjects out of 22 subjects.
ContributorsKrishnan, Ranganath (Author) / Tao, Nongjian (Thesis advisor) / Forzani, Erica (Committee member) / Yu, Hongyu (Committee member) / Arizona State University (Publisher)
Created2012
Description
Windows based mobile application for m-health and environmental monitoring sensor devices were developed and tested. With the number of smartphone users exponentially increasing, the applications developed for m-health and environmental monitoring devices are easy to reach the general public, if the applications are simple, user-friendly and personalized. The sensing device uses Bluetooth to communicate with the smartphone, providing mobility to the user. Since the device is small and hand-held, the user can put his smartphone in his pocket, connected to the device in his hand and can move anywhere with it. The data processing performed in the applications is verified against standard off the shelf software, the results of the tests are discussed in this document. The user-interface is very simple and doesn't require many inputs from the user other than during the initial setting when they have to enter their personal information for the records. The m-health application can be used by doctors as well as by patients. The response of the application is very quick and hence the patients need not wait for a long time to see the results. The environmental monitoring device has a real-time plot displayed on the screen of the smartphone showing concentrations of total volatile organic compounds and airborne particle count in the environment at the location of the device. The programming was done with Microsoft Visual Studio and was written on VB.NET platform. On the applications, the smartphone receives data as raw binary bytes from the device via Bluetooth and this data is processed to obtain the final result. The final result is the concentration of Nitric Oxide in ppb in the Asthma Analyzer device. In the environmental monitoring device, the final result is the concentration of total Volatile Organic Compounds and the count of airborne Particles.
ContributorsGanesan, Srisivapriya (Author) / Tao, Nongjian (Thesis advisor) / Zhang, Yanchao (Committee member) / Tsow, Tsing (Committee member) / Arizona State University (Publisher)
Created2012
Description
Globally, about two-thirds of the population is latently infected with herpes simplex virus type 1 (HSV-1). HSV-1 is a large double stranded DNA virus with a genome size of ~150kbp. Small defective genomes, which minimally contain an HSV-1 origin of replication and packaging signal, arise naturally via recombination during viral DNA replication. These small defective genomes can be mimicked by constructing a bacterial plasmid containing the HSV-1 origin of replication and packaging signal, transfecting these recombinant plasmids into mammalian cells, and infecting with a replicating helper virus. The absence of most viral genes in the amplicon vector allows large pieces of foreign DNA (up to 150kbp) to be incorporated. The HSV-1 amplicon is replicated and packaged by the helper virus to form HSV-1 particles containing the amplicon DNA. We constructed a novel HSV-1 amplicon vector system containing lambda phage-derived attR sites to facilitate insertion of transgenes by Invitrogen Gateway recombination. To demonstrate that the amplicon vectors work as expected, we packaged the vector constructs expressing Emerald GFP using the replication-competent helper viruses OK-14 or HSV-mScartlet-I-UL25 in Vero cells and demonstrate that the vector stock can subsequently transduce and express Emerald GFP. In further work, we will insert transgenes into the amplicon vector using Invitrogen Gateway recombination to study their functionality.
ContributorsVelarde, Kimberly (Author) / Hogue, Ian B (Thesis advisor) / Manfredsson, Fredric (Committee member) / Sandoval, Ivette (Committee member) / Varsani, Arvind (Committee member) / Arizona State University (Publisher)
Created2021
Description
Evolving knowledge about the tumor microenvironment (TME) is driving innovation in designing novel therapies against hard-to-treat breast cancer. Addressing the immune elements within the tumor microenvironment (TME) has emerged as a highly encouraging strategy for treating cancer. Although current immunotherapies have made advancements in reinstating the body's ability to fight tumors, the search for effective cancer treatments to combat tumor evasion remains a formidable challenge. In line with this objective, there is a pressing need to better understand the complex tumor-immune dynamics and crosstalk within the TME. To evaluate the cancer-immune interaction, this study aimed at investigating the crosstalk between naïve macrophages and cytotoxic T cells in driving tumor progression using an organotypic 3D ex vivo tumor on-a-chip model. The presented microfluidic platform consists of two distinct regions namely: The tumor region and the stroma region separated by trapezoidal microposts to ensure interconnectivity between regions thereby incorporating high spatial organization. In the established triculture platform, the complex Tumor Immune Microenvironment was successfully recapitulated by incorporating naïve macrophage and T cells within an appropriate 3D matrix. Through invasion and morphometric analyses, definitive outcomes were obtained that underscore the significant contribution of macrophages in facilitating tumor progression. Furthermore, the inclusion of T cells led to a notable decrease in the migratory speed of cancer cells and macrophages, underscoring the reciprocal communication between these two immune cell populations in the regulation of tumor advancement. Overall, this study highlights the complexity of TME and underscores the critical role of immune cells in regulating cancer progression.
ContributorsManoharan, Twinkle Jina Minette (Author) / Nikkhah, Mehdi (Thesis advisor) / Acharya, Abhinav P (Committee member) / Wang, Shaopeng (Committee member) / Arizona State University (Publisher)
Created2023
Description
Detection technologies and physical methods used for separation of complex molecules can be effective tools in research when applied to bioparticles including, but not limited to,
bacteria, viruses, and proteins. Dielectrophoresis (DEP) is a technique that has been used in
microfluidics for separation and concentration of bioparticles, with the benefits of not requiring
custom primers, utilizing small sample sizes, and relatively quick separation times for rapid
identification of pathogens such as viruses. As demonstrated in this study, a DEP device using
polydimethylsiloxane (PDMS) as an insulator was used for the identification and separation of a
mouse hepatitis coronavirus (MHV), a model coronavirus that only infects mice. Results indicate
that, using 10 microliters of MHV test sample diluted in buffer, the virus can be identified and
separated within 30 seconds using DC voltage of 800 V.
Contributorsmcfadden, matthew (Author) / Hogue, Brenda G (Thesis advisor) / Hayes, Mark (Thesis advisor) / Christen, Jennifer B (Committee member) / Wang, Shaopeng (Committee member) / Arizona State University (Publisher)
Created2023
Description
Obesity has consistently presented a significant challenge, with excess body fat contributing to the development of numerous severe conditions such as diabetes, cardiovascular disease, cancer, and various musculoskeletal disorders. In this study, different methods are proposed to study substrate utilization (carbohydrates, proteins, and fats) in the human body and validate the biomarkers enabling to investigation of weight management and monitor metabolic health. The first technique to study was Indirect calorimetry, which assessed Resting Energy Expenditure (REE) and measured parameters like oxygen consumption (VO2) and carbon dioxide production (VCO2). A validation study was conducted to study the effectiveness of the medical device Breezing Med determining REE, VO2, and VCO2. The results were compared with correlation slopes and regression coefficients close to 1. Indirect Calorimetry can be used to determine carbohydrate and fat utilization but it requires additional correction for protein utilization. Protein utilization can be studied by analyzing urinary nitrogen. Therefore, a secondary technique was studied for identifying urea and ammonia concentration in human urine samples. Along this line two methods for detecting urea were explored, a colorimetric technique and it was validated against the Ion-Selective method. The results were then compared by correlation analysis of urine samples measured with both methods simultaneously curves. The equations for fat, carb, and protein oxidation, involving VO2, VCO2 consumption, and urinary nitrogen were implemented and validated, using the above-described methods in a human subject study with 16 subjects. The measurements included diverse diets (normal vs. high fat/protein) in normal energy balance and pre-/post interventions of exercise, fasting, and a high-fat meal. It can be concluded that the indirect calorimetry portable method in conjunction with urine urea methods are important to help the understanding of substrate utilization in human subjects, and therefore, excellent tools to contribute to the treatments and interventions of obesity and overweighted populations.
ContributorsPradhan, Ayushi (Author) / Forzani, Erica (Thesis advisor) / Lind, Mary Laura (Committee member) / Wang, Shaopeng (Committee member) / Arizona State University (Publisher)
Created2023
Description
Despite the prevalence of coyotes (Canis latrans) little is known about the viruses associated with this species. To assess the extent of viral research that has been conducted on coyotes, a literature review was performed. Over the last six decades, there have been many viruses that have been identified infecting coyotes. The pathology of some cases implies that infection is rare and lethal while others have been demonstrated to be endemic to coyotes. In addition, the majority of the prior analyses were done through serological assays that were limited to investigating target viruses. To help expand what is known about coyote-virus dynamics, viral assays were conducted on coyote scat. The samples were collected as part of transects established along the Salt River near Phoenix, Arizona, United States (USA). The recovered viral genomes were clustered with other deoxynucleic acid (DNA) viruses and analyzed to determine phylogeny and genetic identity. From the recovered viral genomes, there are two novel circoviruses, one novel naryavirus, five unclassified cressdnaviruses, and two previously identified species of anelloviruses from the Wawtorquevirus genus. For these viruses, new phylogenies for their groups and pairwise identity plots have been generated. These figures give insight into the potential hosts and the evolutionary history. In the case of the anelloviruses, they likely derived from a wood rat (Neotoma) host, given the anellovirus family’s host specificity and its similarity to another viral genome derived from a wood rat in Arizona, USA. Of the recovered circovirus genomes, one is associated with a viral isolate collected from a dust sample in Arizona, USA. The second circovirus species identified is within a clade that consists of rodent associated circoviruses and canine circovirus. Other recovered genomes expand clusters of unclassified cressdnaviruses. The recovered genomes support further genomic analysis. These findings help support the notion that there is a wealth of viral information to be identified from animals like coyotes. By understanding the viruses that coyotes are associated with, it is possible to better understand the viral impact on the urban environment, domesticated animals, and wildlife in general.
ContributorsHess, Savage Cree (Author) / Varsani, Arvind (Thesis advisor) / Kraberger, Simona (Committee member) / Upham, Nathan S (Committee member) / Arizona State University (Publisher)
Created2023