Biomedical subjects

Edme H Hardy

Publications and source records attributed to Edme H Hardy.

4 recordsLinked to original sources

PubMed2006

Monitoring the formation of an Aureobasidium pullulans biofilm in a bead-packed reactor via flow-weighted magnetic resonance imaging.

The biofilm-forming fungus, Aureobasidium pullulans DSM 2404, was grown in a bead-packed reactor. Alterations within the reactor were analysed in several cross-sectional slices by magnetic resonance imaging (MRI) with flow contrast. For the first time, biofilm accumulation could be continuously elucidated without using any contrast agents, and the non-stationary flow through the fixed-bed reactor could be visualized. The results indicate that the non-stationary flow through the biofilm reactor changes significantly due to the changing reactor morphology. Preferential flow lines arise during biofilm formation. The accumulation of the biomass was determined and compared to gravimetrical biomass data. The described technique can be used to monitor hydrodynamic transport, and to combine flow-field characteristics with morphological data for the prediction of undesirable reactor processes, e.g. clogging.

Ascomycota↗

PubMed2005

MRI as a key tool for understanding and modeling the filtration kinetics of fibrous media.

Applying MRI techniques to low-density fibrous filter media provides us with unique information about the initial structure and deposited mass within the same filter sample. This now enables us to obtain the necessary link between structure and deposition for validation and further enhancement of modeling filtration kinetics. However, additional work is needed before achieving a realistic understanding of filtration kinetics.

Filtration↗

PubMed2004

Calculation of the deuteron quadrupole relaxation rate in a mixture of water and dimethyl sulfoxide.

An approach is presented that allows NMR relaxation rates to be determined for a complex mixture, and it is applied to a dimethyl sulfoxide/water solution. This approach is novel for such systems, having only been used for simple systems such as atomic liquids or atomic ions in liquids until now. It involves use of a predetermined, quantum mechanical, multidimensional property surface in a simulation. The results are used in conjunction with the simulated rotational correlation time to calculate the deuteron quadrupole coupling constant (DQCC), in an analogous approach to the one used by experimentalists, and to examine the surprising experimental findings for the composition dependence of the DQCC in the dimethyl sulfoxide/water mixture. Experiments have suggested that the DQCC for a mixture of 5% dimethyl sulfoxide in water is close to the DQCC of ice, whereas its value increases to a value close to the gas value with further dilution.(1) The results are further critically analyzed using combinations of different experimental and theoretical results from the literature.

Journal Article↗

PubMed2003

Fast-MAS total through-bond correlation spectroscopy using adiabatic pulses.

Pulse sequences consisting of adiabatic pulses for total through-bond correlation spectroscopy (TOBSY) under magic-angle spinning (MAS) are introduced. Above a certain threshold, the polarization transfer achieved with these sequences is largely insensitive to the amplitude and homogeneity of the radiofrequency field employed. An experimental transfer efficiency of up to 76% was achieved in a two-spin system using the sequence WiW9(24)(1) at a MAS frequency of 26.67 kHz. Applications to resonance assignments in the dipeptide L-Val-L-Phe and in the cyclic decapeptide antamanide are demonstrated.

Algorithms↗