Effect of extrinsic lactic acid on fermentative hydrogen production

In this paper we report the effect of extrinsic lactic acid on hydrogen production from a starch-containing medium by a mixed culture. Study of the effect of addition of four metabolites, namely ethanol, lactic acid, butyric acid and acetic acid illustrated that lactic acid had a positive effect on both the maximum hydrogen production and hydrogen production rate. The addition of 10 mM lactic acid to a batch containing starch increased the hydrogen production rate and hydrogen production yield from 4.31 to 8.23 mL/h and 5.70 to 9.08 mmol H₂/g starch, respectively. This enhancement in hydrogen production rate and yield was associated with a shift from acetic acid and ethanol formation to formation of butyric acid as the predominant metabolite. The increase in hydrogen production yield was attributed to the increase in the available residual NADH for hydrogen production. When lactic acid was used as the sole carbon source, no significant hydrogen production was observed.     

Biodegradation of petroleum hydrocarbons in an immobilized cell airlift bioreactor

An "immobilized cell airlift bioreactor", was used for the aerobic bioremediation of simulated diesel fuel contaminated groundwater and tested with p-xylene and naphthalene in batch and continuous regimes. The innovative design of the experiments consists of two stages. At the first stage "immobilized soil bioreactor" (ISBR) was used to develop an efficient microbial consortium from the indigenous microorganisms, which exist in diesel fuel contaminated soil. The concept of ISBR relies on the entrapment of the soil particles into the pores of a semi-permeable membrane, which divides the bioreactor into two aerated and non-aerated portions. The second stage involves inoculating the "immobilized cell air lift bioreactor" with the cultivated microbial consortia of the first stage. Immobilized cell airlift bioreactor has the same configuration as ISBR except that in this bioreactor instead of soil, microorganisms were immobilized on the fibers of the membrane. The performance of a 0.83 L immobilized cell airlift bioreactor was investigated at various retention time (0.5-6 h) and concentrations of p-xylene (15, 40 and 77 mg/L) and naphthalene (8, 15 and 22 mg/L) in the continuous operation. In the batch regime, 0.9L bioreactor was operated at various biodegradation times (15-135 min) and concentrations of p-xylene (13.6, 44.9 and 67.5 mg/L) and naphthalene (1.5 and 3.8 mg/L). Under the conditions of the complete biodegradation of p-xylene and naphthalene, the obtained volumetric biodegradation rates at biomass density of 720 mg/L were 15 and 16 mg/L h, respectively.     

Interactive focus + context medical data exploration and editing

Volumetric datasets are increasingly used in medical applications. In many of these applications, visualization and interaction is generally performed on cross‐sectional two‐dimensional (2D) views of three‐dimensional (3D) imaging modalities. Displaying 3D volumetric medical datasets on traditional 2D screens can present problems such as occlusion and information overload, especially when multiple data sources are present. Displaying desired information while showing the relationship to the rest of the dataset(s) can be challenging. In this paper, we present an interactive focus + context visualization approach that uses the volumetric Magic Lens interaction paradigm. We propose to use the Magic Lens as a volumetric brush to perform volume editing tasks, therefore combining data exploration with volumetric editing. Polygon‐assisted ray casting methods are used for real‐time rendering and editing frame rates, while providing compact storage of editing states for undo/redo operations. We discuss the application of our methods to radiation therapy, which is an important cancer treatment modality. We envision that this approach will improve the treatment planning process by improving the therapists' understanding of information from various sources and will help identify if the alignment of the patient in the treatment room coincides with the prepared treatment plan. Copyright © 2013 John Wiley & Sons, Ltd.