Boron dilution benchmark using COBAYA3/FLICA4 coupled codes within the NURISP European Project

Within the subproject 3 of the NURISP project three neutron kinetic codes have been implemented into the NURESIM platform. For all three codes (CRONOS2, COBAYA3 and DYN3D) the coupling with the thermal hydraulic code FLICA4 was accomplished using the features of the NURESIM platform. This paper contains the results obtained with COBAYA3/FLICA4 coupled codes for the PWR boron dilution benchmark defined within the sub project 3 of the NURISP project. Results are provided for all the scenarios.

(Table 2B) Geochemistry of Ariadne II sediments corrected for dilution by salt from pore waters and are carbonate free in the eastern South Pacific

Sediment depth is given in mbsf.

The effect of adsorption, filter material and point of dilution on antibiotic elimination by haemofiltration - An in vitro study of levofloxacin

We studied an in vitro model of continuous venous-venous haemofiltration (CVVH), into which levofloxacin 100 mg was infused, to determine levofloxacin adsorption and to determine the effect of filter material and point of dilution (pre- or post-filter) on sieving coefficient. Mean (standard deviation; S.D.) adsorption was 18.7 (5.3) mg for the polyamide filter and 40.2 (2.0) mg for the polyacrylonitrile (PAN) filter (P < 0.001). Post-dilution resulted in a minor, but statistically significant, decrease in sieving coefficient (pre-dilution 0.96 (S.D. 0.10), post-dilution 0.88 (S.D. 0.11) with the PAN filter. These data indicate that the variability in published values for levofloxacin sieving coefficient are not due to variation in point of dilution or membrane type (PAN or polyamide). Significant adsorption of levofloxacin onto PAN filters occurs. (C) 2004 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Stable production of hyaluronic acid in Streptococcus zooppidemicus chemostats operated at high dilution rate

Hyaluronic acid is routinely produced through fermentation of both Group A and C streptococci. Despite significant production costs associated with short fermentations and removal of contaminating proteins released during entry into stationary phase, hyaluronic acid is typically produced in batch rather than continuous culture. The main reason is that hyaluronic acid synthesis has been found to be unstable in continuous culture except at very low dilution rates. Here, we investigated the mechanisms underlying this instability and developed a stable, high dilution rate (0.4 h(-1)) chemostat process for both chemically defined and complex media operating for more than 150 h of production. In chemically defined medium, the product yield was 25% higher in chemostat cultures than in conventional batch culture when arginine or glucose was the limiting substrate. In contrast, glutamine limitation resulted in higher ATP requirements and a yield similar to that observed in batch culture. In complex, glucose-limited medium, ATP requirements were greatly reduced but biomass synthesis was favored over hyaluronic acid and no improvement in hyaluronic acid yield was observed. The successful establishment of continuous culture at high dilution rate enables both commercial production at reduced cost and a more rational characterization and optimization of hyaluronic acid production in streptococci. (c) 2005 Wiley Periodicals, Inc.

Using urea dilution to standardise components of pleural and bronchoalveolar lavage fluids in the dog

AIM: To develop a technique to estimate the volume of epithelial lining fluid (ELF) obtained during bronchoalveolar lavage (BAL) and pleural lavage (PL) in the dog, using the urea dilution method. METHODS: BAL and PL fluids were obtained by saline lavage of pulmonary and pleural cavities of nine clinically healthy mixed-breed dogs immediately after euthanasia. Cell counts in the BAL and PL fluids were measured using standard techniques. The concentration of ELF in each lavage fluid was calculated from the relative concentration of urea in plasma and in each type of lavage fluid. Cell counts in ELF were then calculated. RESULTS: There were substantially higher cell counts in ELF compared to BAL or PF fluid. However, nucleated cell counts in ELF could not be predicted from cell counts in BAL or PL fluid. CONCLUSIONS AND CLINICAL RELEVANCE: These results suggest that accurate assessment of cellular or non-cellular components in lavage fluids should include a calculation of the proportion of ELF recovered, using a method such as urea dilution.

Using urea dilution to standardise cellular and non-cellular components of pleural and bronchoalveolar lavage (BAL) fluids in the cat

A technique to standardise the analysis of cellular and non-cellular components in epithelial lining fluid (ELF) collected during saline lavage of pulmonary and pleural cavities was developed using the urea dilution method. Bronchoalveolar lavage (BAL) and pleural lavage (PL) fluids were collected from 12 clinically healthy cats. Total and differential cell counts in BAL fluid were within normal ranges for the cat, while cell Counts in PL fluid were assumed to be normal based on clinical health during examination, auscultation and lactate dehydrogenase (LDH) activities being comparable with other species. The major clinical implication of this study was that nucleated cell counts within feline ELF could not be predicted from analysis of lavage fluid which suggests that calculation of the proportion of ELF in lavage fluid by the urea dilution method may be necessary to avoid misdiagnosis of health or disease in pulmonary or pleural cavities. (C) 2005 ESFM and AAFP. Published by Elsevier Ltd. All rights reserved.

Dilution versus dialysis - A quantitative study of the oxidative refolding of recombinant human alpha-fetoprotein

Alpha-fetoprotein (AFP) is a commercially important polypeptide with important diagnostic. physiological and immunomodulatory functions. Previous studies into the refolding of this macromolecule are contradictory. and variously suggest that AFP denaturation may be irreversible or that refolding may be achieved by reducing denaturant concentration through dilution but not dialysis. Importantly, these same previous studies do not provide quantitative metrics by which the Success of refolding, and the potential for bioprocess development. can be assessed. Moreover, these same studies do not optimize and control refolding redox potential - an important factor considering that AFP contains 32 cysteines which form 16 disulfide bonds. In this current study, a quantitative comparison of recombinant human AFP (rhAFP) refolding by dilution and dialysis is conducted under optimized redox conditions. rhAFP refolding yields were > 35% (dialysis refolding) and > 75% (dilution refolding) as assessed by RP-HPLC and ELISA, with structural Similarity to the native state confirmed by UV spectroscopy. Dialysis refolding yield was believed to be lower because the gradual reduction in denaturant concentration allowed extended conformational searching. enabling more time for undesirable interaction with other protein molecules and/or the dialysis membrane, leading to a Sub-optimal process outcome. Significant yield sensitivity to redox environment was also observed, emphasizing the importance of physicochemical optimization. This study demonstrates that very high refolding yields can be obtained, for a physiologically relevant protein, with optimized dilution refolding. The study also highlights the quantitative metrics and macromolecular physical spectroscopic 'fingerprints' required to facilitate transition from laboratory to process scale.