Diagnostic Color Strip Reader for World Health Partners Clinics

Despite the advancement of medical technology, many people in developing countries like India and Kenya still suffer from treatable diseases. In many of the health clinics in these areas, color strips are used for checkups and diagnosis of diseases. However, a big problem with these color strips is that the diagnosis of color strips take a long time because they have to be manually checked. Currently, World Health Partners (WHP) works with doctors and hospitals in India and Kenya to provide more accessible healthcare through telehealth networks to get consultations from rural clinics to specialists at hospitals. We are working with WHP to streamline the process of color strip diagnosis, by creating an application that goes through the process of reading a color strip in a single step. Our application analyzes an image of a color strip and returns the concentration of the different factors being tested on the color strip. By doing so, we provide a precise analysis of color strips, instead of having to wait for a specialist

Group key agreement protocols with implicit key authentication

There have been numerous studies performed on secure group communication over unsecured channels such as the Internet and ad-hoc network. Most of the results are focused on cryptographic methods to share secret keys within the group. In the real world, however, we cannot establish an application for group communication without considering authentication of each peer (group member) since the adversary could digitally disguise itself and intrude into the key sharing process without valid membership. Therefore, authentication is an inevitable component for any secure communication protocols as well as peer group communication. In the classical design of group key protocols, each peer should be authenticated by a separate and centralized authentication server (e.g. Kerberos). Although many practical protocols present efficient ways for authentication, we are still facing the necessity of optimization between authentication and group key sharing. In that sense, implicit key authentication is an ideal property for group key protocols since, once it is possibly put into practice, we do not need any separate authentication procedure as a requisite. There was an attempt to devise implicit key authentication service in conjunction with group key agreement protocol; Authenticated Group Diffie-Hellman (A-GDH) and its stronger version (SA-GDH). Unfortunately, both were proved to have some weakness from the man-in-the-middle attacks. In this project, practical fixes for A-GDH and SA-GDH using Message Authentication Code (MAC) schemes are proposed and performance evaluation is carried out from implementation and experimentation for each: A-GDH, SA-GDH, A-GDH with MAC, and SA-GDH with MAC. Finally, the policies how and where to deploy authenticated GDH protocols are discussed under various group communication scenarios

Fabrication of mixed-scale PMMA (Polymethyl methacrylate) fluidic device via thermal nanoimprint using a convex carbon mold

Department of Mechanical EngineeringRecently micro-/nanofluidic devices are widely used for various research areas including biological, chemical, and biomedical applications. Such mixed-scale micro-/nanofluidic devices are generally fabricated using photolithography and direct writing methods (e. g., e-beam lithography or focused ion beam milling) in series. However, the direct writing methods require high cost and long process time thus resulting in low throughput issue. PDMS (Polydimethylsiloxane) replication can overcome the low throughput issues. The PDMS replication method consists of a PDMS casting process on a pre-patterned mold and a subsequent curing processes. By this method, PDMS mixed-scale channel patterns can be replicated repeatedly, thus, total throughput of fabricated mixed-scale PDMS fluidic device is enhanced. However, the channel size is smaller, the more PDMS channels are collapsed due to the low Young???s modulus and hardness of PDMS. In this study, I developed the fabrication method of mixed-scale PMMA (Poly methyl methacrylate) fluidic device via simple thermal nanoimprint using a monolithic mixed-scale convex carbon mold (microchannel mold: width = ~ 50 ???m, height = ~ 5 ???mnanochannel mold: width = ~ 600 nm, height = ~ 60 nm). The monolithic carbon mold was fabricated using carbon-MEMS consisting of two step photolithography processes and one step pyrolysis. In pyrolysis, polymer structures shrank dramatically and thus microscale photoresist structures were converted into sub-micro- or nanoscale carbon structures. In nanoimprint process, the shape of the monolithic mixed-scale convex carbon mold was transferred into a PMMA sheet while the polymer sheet was heated. After demolding the carbon mold from the patterned PMMA sheet, the patterns were accurately transferred on the PMMA sheet (microchannel: width = ~ 50 ???m, height = ~ 5 ???mnanochannel: width = ~ 600 nm, height = ~ 60 nm). The pyrolyzed carbon mold could be easily demolded because of its curved side walls resulting from anisotropic volume reduction in pyrolysis. This special side wall geometry and good robustness of the carbon mold ensured reproducibility in nanoimprint. The mixed-scale channels were sealed by another thin PMMA sheet with low pressure and heat after oxygen plasma treatment. PMMA has higher Young???s modulus compared to PDMS (polydimethylsiloxane) so that the PMMA channels ensured consistent nanochannel fabrication and operation without channel collapse. The PMMA mixed-scale fluidic device was used to entrap single particles via diffusiophoresis. In the fluidic device, microchannels and nanochannels were smoothly connected via Kingfisher-beak-shaped 3D microfunnels that were converted from polymer triangular prims via pyrolysis. By filling two microchannels that are connected via multiple nanochannels with high concentration solution and low concentration solution respectively and controlling pressure difference between two microchannels, local concentration gradients can occur near the 3D microfunnels at the microchannel with low concentration. The localized concentration gradients generate local electric fields resulting in diffusiophoresisthe motion of charged particles along the localized electric fields. In this experiment, 1 ??m-diameter charged single particles dispersed in the low concentrate solution were dragged from the microchannel into the 3D microfunnels via diffusiophoresis. Consequently, the unique 3D microfunnel worked as a chamber where single particle was entrappedthus, single particles could be entrapped without external electric force in 3D microfunnels. The diffusiophoresis-based single particle entrapment experiment showed the potential of the mixed-scale channel networks as a single cell research tool.ope

Optimization and assessment of Omega-3 fatty acids from high-dimensional spectroscopic data in the Atlantic salmon breeding programs

Atlantic salmon is well known as a rich source of Omega-3 fatty acids (in particular, ALA, DHA, and EPA), and these fatty acids are heritable, thus, the selection of parents will influence their levels in the offspring. The gold standard method of recording Omega-3 fatty acids in Atlantic salmon is costly, time-consuming, and destructive to the sample. For selective breeding purposes, a more affordable method is needed to measure Omega-3 fatty acids in thousands of related salmon. In many breeding programs, vibrational spectroscopy is primarily used with the Partial Least Squares Regression (PLSR) model to measure and predict phenotypes such as Omega-3 fatty acids. However, there is a knowledge gap in estimating heritability using vibrational spectroscopy and finding the effect of sample selection and variable selection methods in the data analysis process perspective. Hence, we optimized and assessed the predicted Omega-3 fatty acids from the high-dimensional spectroscopy data (NIR and Raman spectroscopy data) in the breeding program according to the multiple scenarios combined with sample selection (Kennard-Stone and Random Sampling) and variable selection (with or without Markov Blanket). We found that the PLSR model accuracy and the resulting heritability estimates generally increase with adopting the variable selection method. We also found that NIR spectroscopy has a good affinity with Kennard-Stone sampling, while Raman spectroscopy showed stable performance regardless of sample selection. It is possible to achieve improved PLSR model accuracy and heritability estimates by utilizing the Markov Blanket approach