Calibrating SECCM measurements by means of a nanoelectrode ruler.The intrinsic oxygen reduction activity of PtNi catalyst nanoparticles

Scanning electrochemical cell microscopy(SECCM)is increasingly applied to determine the intrinsic catalytic activity of single electrocatalyst particle.This is especially feasible if the catalyst nanoparticles are large enough that they can be found and counted in post-SECCM scanning electron microscopy images.Evidently,this becomes impossible for very small nanoparticles and hence,a catalytic current measured in one landing zone of the SECCM droplet cannot be correlated to the exact number of catalyst particles.We show,that by introducing a ruler method employing a carbon nanoelectrode decorated with a countable number of the same catalyst particles from which the catalytic activity can be determined,the activity determined using SECCM from many spots can be converted in the intrinsic catalytic activity of a certain number of catalyst nanoparticles.     

A novel background updation algorithm using fuzzy c-means clustering for pedestrian detection

Multimedia Tools and Applications - The task of pedestrian detection in video surveillance applications will face challenges like dynamic background changes, false human detection (shadow), and...     

Facility inspection using UAVs: a case study in the University of Georgia campus

ABSTRACT

Facility inspections are an essential factor to maintaining the physical integrity of a building for several years. If inspections and follow up maintenance are only performed when reported, a significant portion of building damages will go unnoticed until the interior of the building is affected. Using unmanned aerial vehicles (UAV) for facility inspections presents a preventative approach to current inspection processes. The proposed technology is based on low-cost, high performance unmanned aerial vehicles integrated with modern sensing technologies for building and infrastructure inspections. The UAV prototype is based on highly developed consumer drone modified with thermal imaging capabilities to maximize visibility for a diverse range of damages. The focus of this case study is the inspection of potential damages associated with water, heat, and the Heating, Ventilation, and Air Conditioning (HVAC) system. Inspections with the assistance of UAVs can visualize areas of a building’s exterior where it is difficult to access or poses a safety risk to the inspector. This work provides a simplistic and cost-effective method to perform spot inspections of facilities. Results confirm that early detection of potential compromising utilities is possible with UAVs, which could prolong the life of equipment and facilities, effectively making the campus more sustainable.     

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. “Dynamic” liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope ¹³C. Hepatocellular metabolization of the substrate will generate ¹³CO₂, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of ¹³CO₂ are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. ¹³C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, ¹³C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. ¹³C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of ¹³C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.