1,128 research outputs found
Research and Development of Palladium/Metal Oxide Based Nanostructures as High-Performance Hydrogen Gas Sensors
An alternative energy source to petroleum is hydrogen fuel-cells, and better hydrogen sensors are needed to detect low hydrogen concentrations to make these fuel-cells safer. Pure palladium hydrogen sensors, based on networks of ultrasmall nanowires sputter-deposited on a filtration membrane have shown promising results, especially when alloyed with other metals or when layered with other metals. Unfortunately, even the best palladium-based hydrogen sensors still cannot distinguish hydrogen concentrations below 3% or at high operating temperatures, thus limiting the safety and application of the sensors. This study reports on new resistance based sensors of alternating nanowire network layers of pure palladium and titanium dioxide. These sensors show promise at sensing both low hydrogen concentrations, as low as 0.01%, and at sensing hydrogen at an operating temperature of 150 degrees Celsius; a step in the direction of sensors that work at temperatures approaching 1000 degrees Celsius. Although the titanium dioxide layers are not as sensitive to hydrogen as the palladium, they help to increase the durability and potential operating temperature of the sensor by providing additional adhesion and sensing properties
The influence of miR-99a on mTOR signaling regulation in colorectal cancer cell lines.
Colorectal cancer (CRC) is the third most common cancer worldwide and the fourth most common cause of death. These are staggering statistics for a disease that can essentially be cured if caught early and the pathology is favorable to therapeutic intervention. There is currently a drastic decrease in five year survival as the cancer stage increases from locally confined disease to metastatic disease. These statistics suggest that although some strides have been made with colon cancer screening and early intervention, there is still much room for improvement in both screening and treatment of CRC. One of the pathways that have been linked to CRC is the mammalian target of rapamycin (mTOR) pathway. Recently this has been the subject of intense study particularly with a view to better targeted drug therapy for colorectal cancer. Much is known about this pathway; however, multiple regulatory elements have yet to be elucidated. MicroRNAs (miRNAs) have been shown to influence some aspects of the mTOR pathway in other cancers, however their role in the mTOR pathway in CRC has yet to be fully explored. The microRNA-99 (miR-99) family of miRNAs has recently been implicated in regulation of mTOR signaling in other diseases. Studies were conducted using normal colon epithelial and CRC cell lines provided the following key findings: 1. Transfection of miRNA-99a mimic into CCD-841 (normal epithelium) and CRC cell lines, HT-29 (Dukes C), HCT-116 (Dukes D), results in a decrease in the amount of phosphorylated mTOR protein in all 3 cell. 2. miRNA-99a transfection also affected expression of downstream protein products, with a decrease phosphorylated S6K1 in HT-29 and CCD-841, while this same transfection showed an increase in this phosphorylated protein in cell line HCT-116. The opposite was observed for protein 4EBP1 after transfection, which showed an increase in phosphorylated 4EBP1 in cell lines HT-29 and CCD-841, but a decrease in phosphorylated protein the HCT-116 cell line. 1. Transfection of miRNA-99a mimic resulted in decreased motility and invasion in cell lines HT-29 and HCT-116 as compared to cell lines transfected with the negative control. Transfection with the miRNA-99a antagomir resulted in increased motility in both CRC cells lines but minimal changes or decrease in invasion. The effects of miRNA-99a on mTOR protein, S6K1 and 4EBP1 were elucidated by this project providing further evidence as to the importance of mTOR inhibition for possible regulation of CRC metastasis. This supports new avenues of study to further understand CRC metastasis as well as possible targets for therapeutic intervention
Evaluation of Corn Rootworm Hybrids
This past summer, corn root worm technologies were evaluated in side-by-side experiments at four locations in Iowa. The objective of this study was to measure and compare the degree of root protection, standability, and yield provided by the three corn rootworm Cry protein technologies and a standard soil insecticide— Aztec 2.1G
Interaction of Downforce Generating Devices and Cooling Air Flow - A Numerical and Experimental Study on Open Wheeled Race Cars
This study reflects on two areas of vehicle aerodynamics, optimising cooling performance and features that will improve the handling of the car. Both areas will have a significant impact on the overall performance of the car and at the same time these areas are linked to each other.
The considered vehicle in this study was the Chalmers Formula Student 2011 Formula SAE car and the flow field was analysed using both numerical simulations as well as performing wind tunnel experiments on a 1:3-scale model of the car.
The focus on increasing downforce without increasing the aerodynamic drag is particularly good in Formula SAE since fuel economy is an event at the competition. Therefore, the intention of this work is to present a study on how undertrays with different design such as added foot plates, diffuser and strakes can improve the downforce and reduce the drag. Apart from this focus has been towards a common issue among open wheeled race cars with the radiator placed behind the front wheels and how changes in this area will influence the handling of the car. Interference effects between these parts were seen as well as the influence on the general aerodynamic performance of the car
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