Media Exchange Performance Test Using the Bradford Assay in an Automated Bioreactor Engineering Model for Space Experiments.

Life science research has been actively carried out in space for a long time using bioreactor equipment, in anticipation of manned space exploration and space tourism. Such studies have reported that the microgravity environment has a negative effect on the human body, including the musculoskeletal system, nervous system, and endocrine system. Bone loss and muscular atrophy are issues that need to be resolved before long-term exposure of the human body to a space environment. To address this problem, Y. K. Kim et al. designed a system in 2015 and performed an evaluation of an automated bioreactor development model (DM) for space experiments. In this study, we developed an automated bioreactor engineering model (EM) based on the previous literature, and conducted media exchange performance testing using the Bradford assay. We used a novel method that allowed quantitative assessment of the media exchange rate versus the conventional assessment method using visual observation with a camera. By measuring the media exchange rate of the automated bioreactor EM, we attempted to verify applicability for the system for space experiments. We expect that the experimental method proposed in this study is useful for logical determination of liquid exchange or circulation in different closed systems.

Carbon Nanostructure of Diesel Soot Particles Emitted from 2 and 4 Stroke Marine Engines Burning Different Fuels.

Diesel soot particles were sampled from 2-stroke and 4-stroke engines that burned two different fuels (Bunker A and C, respectively), and the effects of the engine and fuel types on the structural characteristics of the soot particle were analyzed. The carbon nanostructures of the sampled particles were characterized using various techniques. The results showed that the soot sample collected from the 4-stroke engine, which burned Bunker C, has a higher degree of order of the carbon nanostructure than the sample collected from the 2-stroke engine, which burned Bunker A. Furthermore, the difference in the exhaust gas temperatures originating from the different engine and fuel types can affect the nanostructure of the soot emitted from marine diesel engines.

Quantitative Image Analysis of Carbon Nanostructure of Particles Produced from Combustion Process.

In the present study, the soot particles produced from diffusion flames burning biodiesel fuel were thermophoretically sampled and the carbon nanostructure of soot particles were imaged using a high resolution transmission electron microscopy (HRTEM). The HRTEM images of soot particles were then quantitatively analyzed using a digital image processing algorithm developed and implemented as part of this work. The HRTEM interpretations with an aid of image processing support feasibility of use of the developed image processing technique for carbon nanostructure quantification.